time estimation - Page 208

Determining cause of random latency and loading issues

- by Sherwin Flight

I'm not sure exactly what details to post in regards to my issue, because I'm not sure what is relevant. Prior to the end of September my websites all loaded quickly, in almost all cases. Loading time wasn't usually more than a few seconds. However, since the end of September I noticed a big increase in page loading times. In some cases pages were taking 30 seconds or more to load. I do have a remote monitoring service monitoring some of the sites as well, and the image below shows the response times over the past month. The response times shown at the beginning of this graph were what the usual response times were prior to this issue occurring. You can see that there has been a significant increase in response times from the beginning to the end of this graph. The thing is, the problem is not happening 100% of the time. If I click through the site, or even just keep refreshing the page, about 25% of the time the pages load quickly, the remaining 75% of the time they load slowly. Sometimes the pages take so long to load that they time out, and don't load at all. I have contacted my hosting provider, and they said things at their end was fine. I don't believe the problem is my home internet provider, because all other websites load without a problem. The server is located in Texas, USA. This also raises another interesting point. My remote monitor checks my site from two locations, California, USA, and London, England. As you can see in the chart below the response time is actually shorter when checked from London, which doesn't seem to make sense, since the server is physically closer to the California monitoring location. I would have expected the London monitoring location to have higher response times since they are physically farther away. I should also point out that in some traceroute test I've done it seem like the first connection to the server seems to take the longest, then after that the rest of the page loads quickly. Below is a little chart showing the times for the first connection to the server. So, what could be causing this problem, and what steps can I take to resolve it or at least narrow down the problem? Sending the request to the server was very quick, and receiving the reply back seems pretty quick, but the WAIT time is really long. So it connects, sends the request, but then waits close to 30 seconds before it starts receiving data back. I am also aware that there are things I can do to speed up page loading times, like reducing the number of CSS and JS files used on a page, compressing images, etc. This is not really what the source of the problem is though, because nothing has really changed on the site since before the problem started, and other sites on the same server are loading slowly as well.

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WebCenter Customer Spotlight: Global Village Telecom Ltda

- by me

Author: Peter Reiser - Social Business Evangelist, Oracle WebCenter Solution SummaryGlobal Village Telecom Ltda. (GVT) is a leading Brazilian telecommunications company, developing solutions and providing services for corporate and end users. GVT is located in Curitiba, Brazil, employs 6,000 people and has an annual revenue of around US$1 billion. GVT business objectives were to improve corporate communications, accelerate internal information flow, provide continuous access to the all business files and enable the company’s leadership to provide information to all departments in real time. GVT implemented Oracle WebCenter Content to centralize the company's content and they built a portal to share and find content in real-time. Oracle WebCenter Content enabled GVT to quickly and efficiently integrate communication among all company employees—ensuring that GVT maintain a competitive edge in the market. Human Resources reduced the time required for issuing internal statements to all staff from three weeks to one day. Company OverviewGlobal Village Telecom Ltda. (GVT) is a leading telecommunications company, developing solutions and providing services for corporate and end users. The company offers diverse innovative products and advanced solutions in conventional fixed telephone communications, data transmission, high speed broadband internet services, and voice over IP (VoIP) services for all market segment. GVT is located in Curitiba, Brazil, employs 6,000 people and have an annual revenue of around US$1 billion. Business ChallengesGVT business objectives were to improve corporate communications, accelerate internal information flow, provide continuous access to the all business files and enable the company’s leadership to provide information to all departments in real time. Solution DeployedGVT worked with the Oracle Partner IT7 to deploy Oracle WebCenter Content to securely centralize the company's content such as growth indicators, spreadsheets, and corporate and descriptive project schedules. The solution enabled real-time information sharing through the development of Click GVT, a portal that currently receives 100,000 monthly impressions from employee searches. Business ResultsGVT gained a competitive edge in the communications market by accelerating internal information flow, streamlining the content standardizing information and enabled real-time information sharing and discovery. Human Resources reduced the time required for issuing internal statements to all staff from three weeks to one day. “The competitive nature of telecommunication industry demands rapid information in the internal flow of the company. Oracle WebCenter Content enabled us to quickly and efficiently integrate communication among all company employees—ensuring that we maintain a competitive edge in the market.” Marcel Mendes Filho, Systems Manager, Global Village Telecom Ltda. Additional Information Global Viallage Telecom Ltda Customer Snapshot Oracle WebCenter Content

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Ubuntu Server Cannot Route to the Internet

- by ejes

I've been having this problem for weeks now, and I can't seem to figure out the problem. My server can route the local network and serves it well, however it cannot access the internet. It can't be the router because everything else on this lan can route through the router. I've even switched the ethernet port. Any help would be appreciated. I've tried all the usual places, anyway, here are the configs: root@uhs:~# uname -a Linux uhs 3.0.0-16-generic-pae #28-Ubuntu SMP Fri Jan 27 19:24:01 UTC 2012 i686 i686 i386 GNU/Linux root@uhs:~# cat /etc/network/interfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface # auto eth1 # iface eth1 inet dhcp auto eth0 iface eth0 inet static address 192.168.0.3 netmask 255.255.255.0 broadcast 192.168.0.255 gateway 192.168.0.1 root@uhs:~# ping -c 4 192.168.0.1 PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data. 64 bytes from 192.168.0.1: icmp_req=1 ttl=64 time=0.334 ms 64 bytes from 192.168.0.1: icmp_req=2 ttl=64 time=0.339 ms 64 bytes from 192.168.0.1: icmp_req=3 ttl=64 time=0.324 ms 64 bytes from 192.168.0.1: icmp_req=4 ttl=64 time=0.339 ms --- 192.168.0.1 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 2997ms rtt min/avg/max/mdev = 0.324/0.334/0.339/0.006 ms root@uhs:~# ping -c 4 209.85.145.103 PING 209.85.145.103 (209.85.145.103) 56(84) bytes of data. --- 209.85.145.103 ping statistics --- 4 packets transmitted, 0 received, 100% packet loss, time 3023ms root@uhs:~# ifconfig eth0 Link encap:Ethernet HWaddr 00:0c:6e:a0:92:6e inet addr:192.168.0.3 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::20c:6eff:fea0:926e/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:13131114 errors:0 dropped:0 overruns:0 frame:0 TX packets:10540297 errors:0 dropped:0 overruns:5 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3077922794 (3.0 GB) TX bytes:3827489734 (3.8 GB) Interrupt:10 Base address:0xa000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:7721 errors:0 dropped:0 overruns:0 frame:0 TX packets:7721 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:551950 (551.9 KB) TX bytes:551950 (551.9 KB) root@uhs:~# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.0.1 0.0.0.0 UG 100 0 0 eth0 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 root@uhs:~# # PRETEND Traceroute root@uhs:~# for i in {1..30}; do ping -t $i -c 1 209.85.145.103; done | grep "Time to live exceeded" root@uhs:~#

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How to keep balance / Unlock items / achievement rules

- by Mark Knol

I'm working on an engine for a game, too learn javascript and just because its fun. I'm a flashdeveloper, I know how to build websites. Now making games is a different challenge, javascript is a challenge, but I'd love to learn how to structure code and what patterns are common. I dont mind if the game ever finish, I'm mostly interested in the programming part of it. I dont have a particular endresult in mind, so I'll see where it takes me. I currently have a system where you can buy items. The items cost a specified amount of gold, silver, diamonds etc. When you have selected and bought the item, it takes time before getting rewarded. When time is over, you are getting rewarded with other properties (gold, energy, diamonds). For example, you can buy an apple for 50gold, It takes a minute, you get rewarded with 75energy. Or if you take a run, it cost 50energy, it takes 5minutes, reward is 25gold and 25silver. These definitions is what i call actions. Currently I already have a system where this already works and I can define as much actions with as much properties as I want. The definitions I have kinda looks like this: {id:101, category:544, onInit:{gold:-75}, onComplete:{energy:75}, time:2000, name:"Apple", locked: false} {id:102, category:544, onInit:{gold:-135}, onComplete:{energy:145}, time:2000, name:"Banana", locked: false} {id:106, category:302, onInit:{energy:-50, power: -25}, onComplete:{gold:100, diamonds:2}, time:10000, name:"Run", locked: false} {id:107, category:302, onInit:{energy:-70, silver: -55}, onComplete:{gold:100}, time:10000, name:"Dance", locked: false} {id:108, category:302, onInit:{energy:-230, power: -355}, onComplete:{gold:70, silver:70}, time:10000, name:"Fitness", locked: false} Now, I would love to add a system where I can lock/unlock the actions using achievement rules. Lets say, if you buy 10 apples, you unlock a new action, like bananas which cost more, and reward more. In the future I maybe want to restrict achievements and actions to levels. I am kinda stuck how to structure this. I have 2 questions: Which patterns are used to define achievements? How/where are they defined? Should it be part of the action, or should it be a separate controller? Is it a good idea to register all completed actions to it? I think I want multiple types of achievement rules, Id love to hear some ideas how to develop it. How do you create/find a good balance, so the user does not get stuck or can cheat by repeat a pattern of actions to get too much rewards. I know there is not a simple answer and i'm lacking of a good game-concept, but I wonder if anyone created such a game and how you dealed and played with it.

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best way to "introduce" OOP/OOD to team of experienced C++ engineers

- by DXM

I am looking for an efficient way, that also doesn't come off as an insult, to introduce OOP concepts to existing team members? My teammates are not new to OO languages. We've been doing C++/C# for a long time so technology itself is familiar. However, I look around and without major infusion of effort (mostly in the form of code reviews), it seems what we are producing is C code that happens to be inside classes. There's almost no use of single responsibility principle, abstractions or attempts to minimize coupling, just to name a few. I've seen classes that don't have a constructor but get memset to 0 every time they are instantiated. But every time I bring up OOP, everyone always nods and makes it seem like they know exactly what I'm talking about. Knowing the concepts is good, but we (some more than others) seem to have very hard time applying them when it comes to delivering actual work. Code reviews have been very helpful but the problem with code reviews is that they only occur after the fact so to some it seems we end up rewriting (it's mostly refactoring, but still takes lots of time) code that was just written. Also code reviews only give feedback to an individual engineer, not the entire team. I am toying with the idea of doing a presentation (or a series) and try to bring up OOP again along with some examples of existing code that could've been written better and could be refactored. I could use some really old projects that no one owns anymore so at least that part shouldn't be a sensitive issue. However, will this work? As I said most people have done C++ for a long time so my guess is that a) they'll sit there thinking why I'm telling them stuff they already know or b) they might actually take it as an insult because I'm telling them they don't know how to do the job they've been doing for years if not decades. Is there another approach which would reach broader audience than a code review would, but at the same time wouldn't feel like a punishment lecture? I'm not a fresh kid out of college who has utopian ideals of perfectly designed code and I don't expect that from anyone. The reason I'm writing this is because I just did a review of a person who actually had decent high-level design on paper. However if you picture classes: A - B - C - D, in the code B, C and D all implement almost the same public interface and B/C have one liner functions so that top-most class A is doing absolutely all the work (down to memory management, string parsing, setup negotiations...) primarily in 4 mongo methods and, for all intents and purposes, calls almost directly into D. Update: I'm a tech lead(6 months in this role) and do have full support of the group manager. We are working on a very mature product and maintenance costs are definitely letting themselves be known.

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PeopleSoft New Design Solves Navigation Problem

- by Applications User Experience

Anna Budovsky, User Experience Principal Designer, Applications User Experience In PeopleSoft we strive to improve User Experience on all levels. Simplifying navigation and streamlining access to the most important pages is always an important goal. No one likes to waste time waiting for pages to load and watching a spinning glass going on and on. Those performance-affecting server trips, page-load waits and just-too-many clicks were complained about for a long time. Something had to be done. A few new designs came in PeopleSoft 9.2 helping users to access their everyday work areas easier and faster. For example, Dashboard and Work Center aggregate most accessed information sections on a single page; Related Information allows users to complete transaction-related-research without interrupting a transaction and Secure Search gets users to a specific page directly. Today we’ll talk about the Actions menu. Most PeopleSoft pages are shared between individual products and product lines. It means changing the content on a single page involves Oracle development and quality assurance time for making and testing the changes. In order to streamline the navigation and cut down on accessing PeopleSoft pages one-page-at-a-time, we introduced a new menu design. The new menu allows accessing shared pages without the Oracle development team making any local changes, and it works as an additional one-click-path to specific high-traffic actionable pages. Let’s look at how many steps it took to Change Salary for an employee in HCM 9.1 before: Figure 1. BEFORE: The 6 steps a user would take to Change Salary in PeopleSoft HCM 9.1 In PeopleSoft 9.1 it took 5 steps + page loading time + additional verification time for making sure a correct employee is selected from the table. In PeopleSoft 9.2 it only takes 2 steps. To complete Ad Hoc Change Salary action, the user can start from the HCM Manager's Dashboard, click the Action menu within a table, choose a menu option, and access a correct employee’s details page to take an action. Figure 2. AFTER: The 2 steps a user would take to Change Salary in PeopleSoft HCM 9.2 The new menu is placed on a row level which ensures the user accesses the correct employee’s details page. The Actions menu separates menu options into hierarchical sections which help to scan and access the correct option quickly. The new menu’s small size and its structure enabled users to access high-traffic pages from any page and from any part of the page. No more spinning hourglass, no more multiple pages upload. The flexible design fits anywhere on a page and provides a fast and reliable path to the correct destination within the product. Now users can: Access any target page no matter how far it is buried from the starting point; Reduce navigation and page-load time; Improve productivity and reduce errors. The new menu design is available and widely used in all PeopleSoft 9.2 product lines.

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Need help on a problemset in a programming contest

- by topher

I've attended a local programming contest on my country. The name of the contest is "ACM-ICPC Indonesia National Contest 2013". The contest has ended on 2013-10-13 15:00:00 (GMT +7) and I am still curious about one of the problems. You can find the original version of the problem here. Brief Problem Explanation: There are a set of "jobs" (tasks) that should be performed on several "servers" (computers). Each job should be executed strictly from start time Si to end time Ei Each server can only perform one task at a time. (The complicated thing goes here) It takes some time for a server to switch from one job to another. If a server finishes job Jx, then to start job Jy it will need an intermission time Tx,y after job Jx completes. This is the time required by the server to clean up job Jx and load job Jy. In other word, job Jy can be run after job Jx if and only if Ex + Tx,y = Sy. The problem is to compute the minimum number of servers needed to do all jobs. Example: For example, let there be 3 jobs S(1) = 3 and E(1) = 6 S(2) = 10 and E(2) = 15 S(3) = 16 and E(3) = 20 T(1,2) = 2, T(1,3) = 5 T(2,1) = 0, T(2,3) = 3 T(3,1) = 0, T(3,2) = 0 In this example, we need 2 servers: Server 1: J(1), J(2) Server 2: J(3) Sample Input: Short explanation: The first 3 is the number of test cases, following by number of jobs (the second 3 means that there are 3 jobs for case 1), then followed by Ei and Si, then the T matrix (sized equal with number of jobs). 3 3 3 6 10 15 16 20 0 2 5 0 0 3 0 0 0 4 8 10 4 7 12 15 1 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 8 10 4 7 12 15 1 4 0 50 50 50 50 0 50 50 50 50 0 50 50 50 50 0 Sample Output: Case #1: 2 Case #2: 1 Case #3: 4 Personal Comments: The time required can be represented as a graph matrix, so I'm supposing this as a directed acyclic graph problem. Methods I tried so far is brute force and greedy, but got Wrong Answer. (Unfortunately I don't have my code anymore) Could probably solved by dynamic programming too, but I'm not sure. I really have no clear idea on how to solve this problem. So a simple hint or insight will be very helpful to me.

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How to loop on a JSON object?

- by Damiano

Hello, I have this JSON object: {"time":"123456789", "raw":"chat_history", "data":{ "msg":[ {"time":1111111111, "user":"user1", "text":"text from user1"}, {"time":2222222222, "user":"user2", "text":"text from user2"}, {"time":3333333333, "user":"user3", "text":"text from user3"}, {"time":4444444444, "user":"user4", "text":"text from user4"} ] }} I have to create a FOR to loop the elements of data.msg and print it: I would print these results with the FOR: 11111111111 - user1 - text from users1 22222222222 - user2 - text from users2 33333333333 - user3 - text from users3 44444444444 - user4 - text from users4 Could you help me? Thank you very much

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Cheese won't start

- by Anthony Hohenheim

I can't start Cheese Webcam Booth. It starts loading and there is a brief moment when the window shows up but then it disappears, like it shuts itself down and it's not in system monitor. My webcam works perfectly in Skype video call. I installed and run Camorama and it gave me an error: Could not connect to video device (/dev/video0) Please check connection When I run the lsusb I get this line for my webcam: Bus 002 Device 002: ID 04f2:b210 Chicony Electronics Co., Ltd And for my graphic card, running lspci: VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) It's not a pressing matter, but it bugs my nerves, if it works on Skype, why does Cheese and other programs refuse to run. As I said, it's not a big deal but any help would be appreciated. Running Cheese in terminal: (cheese:11454): Gtk-WARNING **: Attempting to add a widget with type GtkImage to a GtkToggleButton, but as a GtkBin subclass a GtkToggleButton can only contain one widget at a time; it already contains a widget of type GtkLabel (cheese:11454): Gtk-WARNING **: Attempting to add a widget with type GtkImage to a GtkToggleButton, but as a GtkBin subclass a GtkToggleButton can only contain one widget at a time; it already contains a widget of type GtkLabel (cheese:11454): Gtk-WARNING **: Attempting to add a widget with type GtkImage to a GtkToggleButton, but as a GtkBin subclass a GtkToggleButton can only contain one widget at a time; it already contains a widget of type GtkLabel (cheese:11454): Gtk-WARNING **: Attempting to add a widget with type GtkHBox to a GtkButton, but as a GtkBin subclass a GtkButton can only contain one widget at a time; it already contains a widget of type GtkLabel (cheese:11454): Gtk-WARNING **: Attempting to add a widget with type GtkImage to a GtkButton, but as a GtkBin subclass a GtkButton can only contain one widget at a time; it already contains a widget of type GtkLabel (cheese:11454): Gtk-WARNING **: Attempting to add a widget with type GtkHBox to a GtkToggleButton, but as a GtkBin subclass a GtkToggleButton can only contain one widget at a time; it already contains a widget of type GtkLabel (cheese:11454): Gtk-WARNING **: Attempting to add a widget with type GtkImage to a GtkButton, but as a GtkBin subclass a GtkButton can only contain one widget at a time; it already contains a widget of type GtkLabel (cheese:11454): Gdk-WARNING **: The program 'cheese' received an X Window System error. This probably reflects a bug in the program. The error was 'BadDrawable (invalid Pixmap or Window parameter)'. (Details: serial 932 error_code 9 request_code 137 minor_code 9) (Note to programmers: normally, X errors are reported asynchronously; that is, you will receive the error a while after causing it. To debug your program, run it with the --sync command line option to change this behavior. You can then get a meaningful backtrace from your debugger if you break on the gdk_x_error() function.)

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Determining cause of random latency/loading issues

- by Sherwin Flight

I'm not sure exactly what details to post in regards to my issue, because I'm not sure what is relevant. Prior to the end of September my websites all loaded quickly, in almost all cases. Loading time wasn't usually more than a few seconds. However, since the end of September I noticed a big increase in page loading times. In some cases pages were taking 30 seconds or more to load. I do have a remote monitoring service monitoring some of the sites as well, and the image below shows the response times over the past month. The response times shown at the beginning of this graph were what the usual response times were prior to this issue occurring. You can see that there has been a significant increase in response times from the beginning to the end of this graph. The thing is, the problem is not happening 100% of the time. If I click through the site, or even just keep refreshing the page, about 25% of the time the pages load quickly, the remaining 75% of the time they load slowly. Sometimes the pages take so long to load that they time out, and don't load at all. I have contacted my hosting provider, and they said things at their end was fine. I don't believe the problem is my home internet provider, because all other websites load without a problem. The server is located in Texas, USA. This also raises another interesting point. My remote monitor checks my site from two locations, California, USA, and London, England. As you can see in the chart below the response time is actually shorter when checked from London, which doesn't seem to make sense, since the server is physically closer to the California monitoring location. I would have expected the London monitoring location to have higher response times since they are physically farther away. I should also point out that in some traceroute test I've done it seem like the first connection to the server seems to take the longest, then after that the rest of the page loads quickly. Below is a little chart showing the times for the first connection to the server. So, what could be causing this problem, and what steps can I take to resolve it or at least narrow down the problem? Sending the request to the server was very quick, and receiving the reply back seems pretty quick, but the WAIT time is really long. So it connects, sends the request, but then waits close to 30 seconds before it starts receiving data back. I am also aware that there are things I can do to speed up page loading times, like reducing the number of css/js files used on a page, compressing images, etc. This is not really what the source of the problem is though, because nothing has really changed on the site since before the problem started, and other sites on the same server are loading slowly as well. Any help or advice is much appreciated.

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How to create pulsating value from 0..1..0..1..0 etc for a given duration?

- by pollux

Hi I'm working on some code where I have a Time object with a member time. Time.time gives me the time since my application started in seconds (float value). Now I want to create a pulsating value between 0 and 1 and then from 1 to 0 again, which continues doing thins untill the application stops. I was thinking to use sin() but don't know what to pass to it as paramters to create this pulsing value. How would I create this pulsating value? Kind regards, Pollux

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data from few MySQL tables sorted by ASC

- by Andrew

In the dbase I 've few tables named as aaa_9xxx, aaa_9yyy, aaa_9zzz. I want to find all data with a specified DATE and show it with the TIME ASC. First, I must find a tables in the dbase: $STH_1a = $DBH->query("SELECT table_name FROM information_schema.tables WHERE table_name LIKE 'aaa\_9%' "); foreach($STH_1a as $row) { $table_name_s1[] = $row['table_name']; } Second, I must find a data wit a concrete date and show it with TIME ASC: foreach($table_name_s1 as $table_name_1) { $STH_1a2 = $DBH->query("SELECT * FROM `$table_name_1` WHERE date = '2011-11-11' ORDER BY time ASC "); while ($row = $STH_1a2->fetch(PDO::FETCH_ASSOC)) { echo " ".$table_name_1."-".$row['time']."-".$row['ei_name']." <br>"; } } .. but it shows the data sorted by tables name, then by TIME ASC. I must to have all this data (from all tables) sorted by TIME ASC. Thank You dev-null-dweller, Andrew Stubbs and Jaison Erick for your help. I test the Erick solution : foreach($STH_1a as $row) { $stmts[] = sprintf('SELECT * FROM %s WHERE date="%s"', $row['table_name'], '2011-11-11'); } $stmt = implode("\nUNION\n", $stmts); $stmt .= "\nORDER BY time ASC"; $STH_1a2 = $DBH->query($stmt); while ($row_1a2 = $STH_1a2->fetch(PDO::FETCH_ASSOC)) { echo " ".$row['table_name']."-".$row_1a2['time']."-".$row_1a2['ei_name']." <br>"; } it's working but I've problem with 'table_name' - it's always the LAST table name. //---------------------------------------------------------------------- end the ending solution with all fixes, thanks all for your help, :)) foreach($STH_1a as $row) { $stmts[] = sprintf("SELECT *, '%s' AS table_name FROM %s WHERE date='%s'", $row['table_name'], $row['table_name'], '2011-11- 11'); } $stmt = implode("\nUNION\n", $stmts); $stmt .= "\nORDER BY time ASC"; $STH_1a2 = $DBH->query($stmt); while ($row_1a2 = $STH_1a2->fetch(PDO::FETCH_ASSOC)) { echo " ".$row_1a2['table_name']."-".$row_1a2['time']."-".$row_1a2['ei_name']." <br>"; }

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run php script continuously ..

- by nicky

i have a database in sql which have entries of time there are more than 1000 entries of time . i want to extract time and run a php script exactly at that time.. i have tried to run a php script continuously which check the time but my server doent allo to run more than 60 seconds

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PHP MySQL Select multiple tables

- by Jordan Pagaduan

Is it posibble to select 3 tables at a time in 1 database? Table 1: employee -- employee_id -- first_name -- last_name -- middle_name -- birthdate -- address -- gender -- image -- salary Table 2: logs -- log_id -- full_name -- employee_id -- date -- time -- status Table 2: logout -- log_id -- full_name -- employee_id -- date -- time -- status I wanted to get the value of employee table where $id of selected. Then the $id also get the value of log.time, log.date, logout.time, and logout.date. I already try using UNION but nothing happens.

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How do I find difference between times in different timezones in Python?

- by JasonA

Hi All, I am trying to calculate difference(in seconds) between two date/times formatted as following: 2010-05-11 17:07:33 UTC 2010-05-11 17:07:33 EDT time1 = '2010-05-11 17:07:33 UTC' time2 = '2010-05-11 17:07:33 EDT' delta = time.mktime(time.strptime(time1,"%Y-%m-%d %H:%M:%S %Z"))-\ time.mktime(time.strptime(time2, "%Y-%m-%d %H:%M:%S %Z")) The problem I got is EDT is not recognized, the specific error is "ValueError: time data '2010-05-11 17:07:33 EDT' does not match format '%Y-%m-%d %H:%M:%S %Z'" Thanks,

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C# equivalent of typeof for fields

- by rwallace

With reflection, you can look up a class from a string at run time, but you can also say typeof(Foo) and get compile time type checking, auto completion etc. If what you want is a field not a class, you can look it up from a string at runtime, but if you want compile time type checking etc., is there anyway to say something like fieldof(Foo.Bar)? I know the name of both the class and the field in advance, and I want to be able to refer to the field at compile time rather than with a run-time string lookup.

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Is it possible to run dhcpd3 as non-root user in a chroot jail?

- by Lenain

Hi everyone. I would like to run dhcpd3 from a chroot jail on Debian Lenny. At the moment, I can run it as root from my jail. Now I want to do this as non-root user (as "-u blah -t /path/to/jail" Bind option). If I start my process like this : start-stop-daemon --chroot /home/jails/dhcp --chuid dhcp \ --start --pidfile /home/jails/dhcp/var/run/dhcp.pid --exec /usr/sbin/dhcpd3 I get stuck with these errors : Internet Systems Consortium DHCP Server V3.1.1 Copyright 2004-2008 Internet Systems Consortium. All rights reserved. For info, please visit http://www.isc.org/sw/dhcp/ unable to create icmp socket: Operation not permitted Wrote 0 deleted host decls to leases file. Wrote 0 new dynamic host decls to leases file. Wrote 0 leases to leases file. Open a socket for LPF: Operation not permitted strace : brk(0) = 0x911b000 fcntl64(0, F_GETFD) = 0 fcntl64(1, F_GETFD) = 0 fcntl64(2, F_GETFD) = 0 access("/etc/suid-debug", F_OK) = -1 ENOENT (No such file or directory) access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb775d000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = -1 ENOENT (No such file or directory) open("/lib/tls/i686/cmov/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/tls/i686/cmov", 0xbfc2ac84) = -1 ENOENT (No such file or directory) open("/lib/tls/i686/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/tls/i686", 0xbfc2ac84) = -1 ENOENT (No such file or directory) open("/lib/tls/cmov/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/tls/cmov", 0xbfc2ac84) = -1 ENOENT (No such file or directory) open("/lib/tls/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/tls", 0xbfc2ac84) = -1 ENOENT (No such file or directory) open("/lib/i686/cmov/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i686/cmov", 0xbfc2ac84) = -1 ENOENT (No such file or directory) open("/lib/i686/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i686", 0xbfc2ac84) = -1 ENOENT (No such file or directory) open("/lib/cmov/libc.so.6", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/cmov", 0xbfc2ac84) = -1 ENOENT (No such file or directory) open("/lib/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\260e\1\0004\0\0\0t"..., 512) = 512 fstat64(3, {st_mode=S_IFREG|0755, st_size=1294572, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb775c000 mmap2(NULL, 1300080, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb761e000 mmap2(0xb7756000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x138) = 0xb7756000 mmap2(0xb7759000, 9840, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7759000 close(3) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb761d000 set_thread_area({entry_number:-1 - 6, base_addr:0xb761d6b0, limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1, seg_not_present:0, useable:1}) = 0 mprotect(0xb7756000, 4096, PROT_READ) = 0 open("/dev/null", O_RDWR) = 3 close(3) = 0 brk(0) = 0x911b000 brk(0x913c000) = 0x913c000 socket(PF_FILE, SOCK_DGRAM, 0) = 3 fcntl64(3, F_SETFD, FD_CLOEXEC) = 0 connect(3, {sa_family=AF_FILE, path="/dev/log"...}, 110) = 0 time(NULL) = 1284760816 open("/etc/localtime", O_RDONLY) = 4 fstat64(4, {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 fstat64(4, {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb761c000 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\f\0\0\0\f\0\0\0\0\0"..., 4096) = 2945 _llseek(4, -28, [2917], SEEK_CUR) = 0 read(4, "\nCET-1CEST,M3.5.0,M10.5.0/3\n"..., 4096) = 28 close(4) = 0 munmap(0xb761c000, 4096) = 0 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: Intern"..., 73, MSG_NOSIGNAL) = 73 write(2, "Internet Systems Consortium DHCP "..., 46Internet Systems Consortium DHCP Server V3.1.1) = 46 write(2, "\n"..., 1 ) = 1 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: Copyri"..., 75, MSG_NOSIGNAL) = 75 write(2, "Copyright 2004-2008 Internet Syst"..., 48Copyright 2004-2008 Internet Systems Consortium.) = 48 write(2, "\n"..., 1 ) = 1 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: All ri"..., 47, MSG_NOSIGNAL) = 47 write(2, "All rights reserved."..., 20All rights reserved.) = 20 write(2, "\n"..., 1 ) = 1 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: For in"..., 77, MSG_NOSIGNAL) = 77 write(2, "For info, please visit http://www"..., 50For info, please visit http://www.isc.org/sw/dhcp/) = 50 write(2, "\n"..., 1 ) = 1 socket(PF_FILE, SOCK_STREAM, 0) = 4 fcntl64(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(4, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(4) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 4 fcntl64(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(4, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(4) = 0 open("/etc/nsswitch.conf", O_RDONLY) = 4 fstat64(4, {st_mode=S_IFREG|0644, st_size=475, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb761c000 read(4, "# /etc/nsswitch.conf\n#\n# Example "..., 4096) = 475 read(4, ""..., 4096) = 0 close(4) = 0 munmap(0xb761c000, 4096) = 0 open("/lib/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/lib/tls/i686/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/tls/i686/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/tls/i686/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/tls/i686", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/tls/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/tls/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/tls/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/tls", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i686/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i686/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i686/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i686", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/lib/i486-linux-gnu/tls/i686/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i486-linux-gnu/tls/i686/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/lib/i486-linux-gnu/tls/i686/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i486-linux-gnu/tls/i686", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/lib/i486-linux-gnu/tls/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i486-linux-gnu/tls/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/lib/i486-linux-gnu/tls/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i486-linux-gnu/tls", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/lib/i486-linux-gnu/i686/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i486-linux-gnu/i686/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/lib/i486-linux-gnu/i686/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i486-linux-gnu/i686", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/lib/i486-linux-gnu/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i486-linux-gnu/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/lib/i486-linux-gnu/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/lib/i486-linux-gnu", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i486-linux-gnu/tls/i686/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i486-linux-gnu/tls/i686/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i486-linux-gnu/tls/i686/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i486-linux-gnu/tls/i686", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i486-linux-gnu/tls/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i486-linux-gnu/tls/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i486-linux-gnu/tls/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i486-linux-gnu/tls", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i486-linux-gnu/i686/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i486-linux-gnu/i686/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i486-linux-gnu/i686/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i486-linux-gnu/i686", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i486-linux-gnu/cmov/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i486-linux-gnu/cmov", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/usr/lib/i486-linux-gnu/libnss_db.so.2", O_RDONLY) = -1 ENOENT (No such file or directory) stat64("/usr/lib/i486-linux-gnu", 0xbfc2ad5c) = -1 ENOENT (No such file or directory) open("/lib/libnss_files.so.2", O_RDONLY) = 4 read(4, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320\30\0\0004\0\0\0\250"..., 512) = 512 fstat64(4, {st_mode=S_IFREG|0644, st_size=38408, ...}) = 0 mmap2(NULL, 41624, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0xb7612000 mmap2(0xb761b000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x8) = 0xb761b000 close(4) = 0 open("/etc/services", O_RDONLY|O_CLOEXEC) = 4 fcntl64(4, F_GETFD) = 0x1 (flags FD_CLOEXEC) fstat64(4, {st_mode=S_IFREG|0644, st_size=18480, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7611000 read(4, "# Network services, Internet styl"..., 4096) = 4096 read(4, "9/tcp\t\t\t\t# Quick Mail Transfer Pr"..., 4096) = 4096 read(4, "note\t1352/tcp\tlotusnotes\t# Lotus "..., 4096) = 4096 read(4, "tion\nafs3-kaserver\t7004/udp\nafs3-"..., 4096) = 4096 read(4, "backup\t2989/tcp\t\t\t# Afmbackup sys"..., 4096) = 2096 read(4, ""..., 4096) = 0 close(4) = 0 munmap(0xb7611000, 4096) = 0 time(NULL) = 1284760816 open("/etc/protocols", O_RDONLY|O_CLOEXEC) = 4 fstat64(4, {st_mode=S_IFREG|0644, st_size=2626, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7611000 read(4, "# Internet (IP) protocols\n#\n# Upd"..., 4096) = 2626 close(4) = 0 munmap(0xb7611000, 4096) = 0 socket(PF_INET, SOCK_RAW, IPPROTO_ICMP) = -1 EPERM (Operation not permitted) time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: unable"..., 80, MSG_NOSIGNAL) = 80 write(2, "unable to create icmp socket: Ope"..., 53unable to create icmp socket: Operation not permitted) = 53 write(2, "\n"..., 1 ) = 1 open("/etc/dhcp3/dhcpd.conf", O_RDONLY) = 4 lseek(4, 0, SEEK_END) = 1426 lseek(4, 0, SEEK_SET) = 0 read(4, "#----------------------------\n# G"..., 1426) = 1426 close(4) = 0 mmap2(NULL, 401408, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb75b0000 mmap2(NULL, 401408, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb754e000 mmap2(NULL, 401408, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb74ec000 brk(0x916f000) = 0x916f000 close(3) = 0 socket(PF_FILE, SOCK_DGRAM, 0) = 3 fcntl64(3, F_SETFD, FD_CLOEXEC) = 0 connect(3, {sa_family=AF_FILE, path="/dev/log"...}, 110) = 0 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: Inter"..., 74, MSG_NOSIGNAL) = 74 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: Copyr"..., 76, MSG_NOSIGNAL) = 76 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: All r"..., 48, MSG_NOSIGNAL) = 48 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: For i"..., 78, MSG_NOSIGNAL) = 78 open("/var/lib/dhcp3/dhcpd.leases", O_RDONLY) = 4 lseek(4, 0, SEEK_END) = 126 lseek(4, 0, SEEK_SET) = 0 read(4, "# The format of this file is docu"..., 126) = 126 close(4) = 0 open("/var/lib/dhcp3/dhcpd.leases", O_WRONLY|O_CREAT|O_APPEND, 0666) = 4 fstat64(4, {st_mode=S_IFREG|0644, st_size=126, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb74eb000 fstat64(4, {st_mode=S_IFREG|0644, st_size=126, ...}) = 0 _llseek(4, 126, [126], SEEK_SET) = 0 time(NULL) = 1284760816 time(NULL) = 1284760816 open("/var/lib/dhcp3/dhcpd.leases.1284760816", O_WRONLY|O_CREAT|O_TRUNC, 0664) = 5 fcntl64(5, F_GETFL) = 0x1 (flags O_WRONLY) fstat64(5, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb74ea000 _llseek(5, 0, [0], SEEK_CUR) = 0 close(4) = 0 munmap(0xb74eb000, 4096) = 0 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: Wrote"..., 70, MSG_NOSIGNAL) = 70 write(2, "Wrote 0 deleted host decls to lea"..., 42Wrote 0 deleted host decls to leases file.) = 42 write(2, "\n"..., 1 ) = 1 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: Wrote"..., 74, MSG_NOSIGNAL) = 74 write(2, "Wrote 0 new dynamic host decls to"..., 46Wrote 0 new dynamic host decls to leases file.) = 46 write(2, "\n"..., 1 ) = 1 time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: Wrote"..., 58, MSG_NOSIGNAL) = 58 write(2, "Wrote 0 leases to leases file."..., 30Wrote 0 leases to leases file.) = 30 write(2, "\n"..., 1 ) = 1 write(5, "# The format of this file is docu"..., 126) = 126 fsync(5) = 0 unlink("/var/lib/dhcp3/dhcpd.leases~") = 0 link("/var/lib/dhcp3/dhcpd.leases", "/var/lib/dhcp3/dhcpd.leases~") = 0 rename("/var/lib/dhcp3/dhcpd.leases.1284760816", "/var/lib/dhcp3/dhcpd.leases") = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP) = 4 ioctl(4, SIOCGIFCONF, {0 - 64, NULL}) = 0 ioctl(4, SIOCGIFCONF, {64, {{"lo", {AF_INET, inet_addr("127.0.0.1")}}, {"eth0", {AF_INET, inet_addr("192.168.0.10")}}}}) = 0 ioctl(4, SIOCGIFFLAGS, {ifr_name="lo", ifr_flags=IFF_UP|IFF_LOOPBACK|IFF_RUNNING}) = 0 ioctl(4, SIOCGIFFLAGS, {ifr_name="eth0", ifr_flags=IFF_UP|IFF_BROADCAST|IFF_RUNNING|IFF_MULTICAST}) = 0 ioctl(4, SIOCGIFHWADDR, {ifr_name="eth0", ifr_hwaddr=00:c0:26:87:55:c0}) = 0 socket(PF_PACKET, SOCK_PACKET, 768) = -1 EPERM (Operation not permitted) time(NULL) = 1284760816 stat64("/etc/localtime", {st_mode=S_IFREG|0644, st_size=2945, ...}) = 0 send(3, "Sep 18 00:00:16 dhcpd: Open "..., 74, MSG_NOSIGNAL) = 74 write(2, "Open a socket for LPF: Operation "..., 46Open a socket for LPF: Operation not permitted) = 46 write(2, "\n"..., 1 ) = 1 exit_group(1) = ? I understand that dhcpd wants to create sockets on port 67... but I don't know how to authorize that through the chroot. Any idea?

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Red Gate Coder interviews: Alex Davies

- by Michael Williamson

Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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Hanging of host network connections when starting KVM guest on bridge

- by Chris Phillips

Hi, I've a KVM system upon which I'm running a network bridge directly between all VM's and a bond0 (eth0, eth1) on the host OS. As such, all machines are presented on the same subnet, available outside of the box. The bond is doing mode 1 active / passive, with an arp_ip_target set to the default gateway, which has caused some issues in itself, but I can't see the bond configs mattering here myself. I'm seeing odd things most times when I stop and start a guest on the platform, in that on the host I lose network connectivity (icmp, ssh) for about 30 seconds. I don't lose connectivity on the other already running VM's though... they can always ping the default GW, but the host can't. I say "about 30 seconds" but from some tests it actually seems to be 28 seconds usually (or at least, I lose 28 pings...) and I'm wondering if this somehow relates to the bridge config. I'm not running STP on the bridge at all, and the forwarding delay is set to 1 second, path cost on the bond0 lowered to 10 and port priority of bond0 also lowered to 1. As such I don't think that the bridge should ever be able to think that bond0 is not connected just fine (as continued guest connectivity implies) yet the IP of the host, which is on the bridge device (... could that matter?? ) becomes unreachable. I'm fairly sure it's about the bridged networking, but at the same time as this happens when a VM is started there are clearly loads of other things also happening so maybe I'm way off the mark. Lack of connectivity: # ping 10.20.11.254 PING 10.20.11.254 (10.20.11.254) 56(84) bytes of data. 64 bytes from 10.20.11.254: icmp_seq=1 ttl=255 time=0.921 ms 64 bytes from 10.20.11.254: icmp_seq=2 ttl=255 time=0.541 ms type=1700 audit(1293462808.589:325): dev=vnet6 prom=256 old_prom=0 auid=42949672 95 ses=4294967295 type=1700 audit(1293462808.604:326): dev=vnet7 prom=256 old_prom=0 auid=42949672 95 ses=4294967295 type=1700 audit(1293462808.618:327): dev=vnet8 prom=256 old_prom=0 auid=42949672 95 ses=4294967295 kvm: 14116: cpu0 unimplemented perfctr wrmsr: 0x186 data 0x130079 kvm: 14116: cpu0 unimplemented perfctr wrmsr: 0xc1 data 0xffdd694a kvm: 14116: cpu0 unimplemented perfctr wrmsr: 0x186 data 0x530079 64 bytes from 10.20.11.254: icmp_seq=30 ttl=255 time=0.514 ms 64 bytes from 10.20.11.254: icmp_seq=31 ttl=255 time=0.551 ms 64 bytes from 10.20.11.254: icmp_seq=32 ttl=255 time=0.437 ms 64 bytes from 10.20.11.254: icmp_seq=33 ttl=255 time=0.392 ms brctl output of relevant bridge: # brctl showstp brdev brdev bridge id 8000.b2e1378d1396 designated root 8000.b2e1378d1396 root port 0 path cost 0 max age 19.99 bridge max age 19.99 hello time 1.99 bridge hello time 1.99 forward delay 0.99 bridge forward delay 0.99 ageing time 299.95 hello timer 0.50 tcn timer 0.00 topology change timer 0.00 gc timer 0.04 flags vnet5 (3) port id 8003 state forwarding designated root 8000.b2e1378d1396 path cost 100 designated bridge 8000.b2e1378d1396 message age timer 0.00 designated port 8003 forward delay timer 0.00 designated cost 0 hold timer 0.00 flags vnet0 (2) port id 8002 state forwarding designated root 8000.b2e1378d1396 path cost 100 designated bridge 8000.b2e1378d1396 message age timer 0.00 designated port 8002 forward delay timer 0.00 designated cost 0 hold timer 0.00 flags bond0 (1) port id 0001 state forwarding designated root 8000.b2e1378d1396 path cost 10 designated bridge 8000.b2e1378d1396 message age timer 0.00 designated port 0001 forward delay timer 0.00 designated cost 0 hold timer 0.00 flags I do see the new port listed as learning, but in line with the forward delay, only for 1 or 2 seconds when polling the brctl output on a loop. All pointers, tips or stabs in the dark appreciated.

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Parallel processing slower than sequential?

- by zebediah49

EDIT: For anyone who stumbles upon this in the future: Imagemagick uses a MP library. It's faster to use available cores if they're around, but if you have parallel jobs, it's unhelpful. Do one of the following: do your jobs serially (with Imagemagick in parallel mode) set MAGICK_THREAD_LIMIT=1 for your invocation of the imagemagick binary in question. By making Imagemagick use only one thread, it slows down by 20-30% in my test cases, but meant I could run one job per core without issues, for a significant net increase in performance. Original question: While converting some images using ImageMagick, I noticed a somewhat strange effect. Using xargs was significantly slower than a standard for loop. Since xargs limited to a single process should act like a for loop, I tested that, and found it to be about the same. Thus, we have this demonstration. Quad core (AMD Athalon X4, 2.6GHz) Working entirely on a tempfs (16g ram total; no swap) No other major loads Results: /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 1 convert -auto-level real 0m3.784s user 0m2.240s sys 0m0.230s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 2 convert -auto-level real 0m9.097s user 0m28.020s sys 0m0.910s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 10 convert -auto-level real 0m9.844s user 0m33.200s sys 0m1.270s Can anyone think of a reason why running two instances of this program takes more than twice as long in real time, and more than ten times as long in processor time to complete the same task? After that initial hit, more processes do not seem to have as significant of an effect. I thought it might have to do with disk seeking, so I did that test entirely in ram. Could it have something to do with how Convert works, and having more than one copy at once means it cannot use processor cache as efficiently or something? EDIT: When done with 1000x 769KB files, performance is as expected. Interesting. /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 1 convert -auto-level real 3m37.679s user 5m6.980s sys 0m6.340s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 1 convert -auto-level real 3m37.152s user 5m6.140s sys 0m6.530s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 2 convert -auto-level real 2m7.578s user 5m35.410s sys 0m6.050s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 4 convert -auto-level real 1m36.959s user 5m48.900s sys 0m6.350s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 10 convert -auto-level real 1m36.392s user 5m54.840s sys 0m5.650s

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Speed up SQL Server queries with PREFETCH

- by Akshay Deep Lamba

Problem The SAN data volume has a throughput capacity of 400MB/sec; however my query is still running slow and it is waiting on I/O (PAGEIOLATCH_SH). Windows Performance Monitor shows data volume speed of 4MB/sec. Where is the problem and how can I find the problem? Solution This is another summary of a great article published by R. Meyyappan at www.sqlworkshops.com. In my opinion, this is the first article that highlights and explains with working examples how PREFETCH determines the performance of a Nested Loop join. First of all, I just want to recall that Prefetch is a mechanism with which SQL Server can fire up many I/O requests in parallel for a Nested Loop join. When SQL Server executes a Nested Loop join, it may or may not enable Prefetch accordingly to the number of rows in the outer table. If the number of rows in the outer table is greater than 25 then SQL will enable and use Prefetch to speed up query performance, but it will not if it is less than 25 rows. In this section we are going to see different scenarios where prefetch is automatically enabled or disabled. These examples only use two tables RegionalOrder and Orders. If you want to create the sample tables and sample data, please visit this site www.sqlworkshops.com. The breakdown of the data in the RegionalOrders table is shown below and the Orders table contains about 6 million rows. In this first example, I am creating a stored procedure against two tables and then execute the stored procedure. Before running the stored proceudre, I am going to include the actual execution plan. --Example provided by www.sqlworkshops.com --Create procedure that pulls orders based on City --Do not forget to include the actual execution plan CREATE PROC RegionalOrdersProc @City CHAR(20) AS BEGIN DECLARE @OrderID INT, @OrderDetails CHAR(200) SELECT @OrderID = o.OrderID, @OrderDetails = o.OrderDetails FROM RegionalOrders ao INNER JOIN Orders o ON (o.OrderID = ao.OrderID) WHERE City = @City END GO SET STATISTICS time ON GO --Example provided by www.sqlworkshops.com --Execute the procedure with parameter SmallCity1 EXEC RegionalOrdersProc 'SmallCity1' GO After running the stored procedure, if we right click on the Clustered Index Scan and click Properties we can see the Estimated Numbers of Rows is 24. If we right click on Nested Loops and click Properties we do not see Prefetch, because it is disabled. This behavior was expected, because the number of rows containing the value ‘SmallCity1’ in the outer table is less than 25. Now, if I run the same procedure with parameter ‘BigCity’ will Prefetch be enabled? --Example provided by www.sqlworkshops.com --Execute the procedure with parameter BigCity --We are using cached plan EXEC RegionalOrdersProc 'BigCity' GO As we can see from the below screenshot, prefetch is not enabled and the query takes around 7 seconds to execute. This is because the query used the cached plan from ‘SmallCity1’ that had prefetch disabled. Please note that even if we have 999 rows for ‘BigCity’ the Estimated Numbers of Rows is still 24. Finally, let’s clear the procedure cache to trigger a new optimization and execute the procedure again. DBCC freeproccache GO EXEC RegionalOrdersProc 'BigCity' GO This time, our procedure runs under a second, Prefetch is enabled and the Estimated Number of Rows is 999. The RegionalOrdersProc can be optimized by using the below example where we are using an optimizer hint. I have also shown some other hints that could be used as well. --Example provided by www.sqlworkshops.com --You can fix the issue by using any of the following --hints --Create procedure that pulls orders based on City DROP PROC RegionalOrdersProc GO CREATE PROC RegionalOrdersProc @City CHAR(20) AS BEGIN DECLARE @OrderID INT, @OrderDetails CHAR(200) SELECT @OrderID = o.OrderID, @OrderDetails = o.OrderDetails FROM RegionalOrders ao INNER JOIN Orders o ON (o.OrderID = ao.OrderID) WHERE City = @City --Hinting optimizer to use SmallCity2 for estimation OPTION (optimize FOR (@City = 'SmallCity2')) --Hinting optimizer to estimate for the currnet parameters --option (recompile) --Hinting optimize not to use histogram rather --density for estimation (average of all 3 cities) --option (optimize for (@City UNKNOWN)) --option (optimize for UNKNOWN) END GO Conclusion, this tip was mainly aimed at illustrating how Prefetch can speed up query execution and how the different number of rows can trigger this.

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Installation problem Ubuntu 12.04 Crashing hardware error

- by user93640

I am running on Ubuntu 8.04 for quite some time without many problems. About almost a year ago or so I have been trying to upgrade to 10.04 LTS, but without any success. Each time when trying to upgrade or even newly install the installation process crashed after about an hour or so (I forgot exactly how long). Now I wanted to try Ubuntu 12.04 (not even installing, but I only selected "Try Ubuntu without installing") and I got similar errors. I did not try to install it, because of earlier experience with 10.04 when after I also lost 8.04 and had to install from scratch again (after which it worked). I get the following screen (as I am not allowed to upload photos here the text): 26.767262] [Hardware Error]: CPU 0: Machine Check Exception: 0 Bank 5: b200001804000e0f 26.767279] [Hardware Error]: TSC 0 26.767287] [Hardware Error]: PROCESSOR 0:6f6 TIME 1349017924 SOCKET 0 APIC 0 microcode 44 26.767297] [Hardware Error]: Run the above through 'mcelog --ascii' 26.767307] [Hardware Error]: CPU 1: Machine Check Exception: 0 Bank 1: b200000000000175 26.767316] [Hardware Error]: TSC 0 26.767323] [Hardware Error]: PROCESSOR 0:6f6 TIME 1349017924 SOCKET 0 APIC 1 microcode 44 26.767331] [Hardware Error]: Run the above through 'mcelog --ascii' 26.767339] [Hardware Error]: CPU 1: Machine Check Exception: 0 Bank 5: b200003000000e0f 26.767348] [Hardware Error]: TSC 0 26.767354] [Hardware Error]: PROCESSOR 0:6f6 TIME 1349017924 SOCKET 0 APIC 1 microcode 44 26.767363] [Hardware Error]: Run the above through 'mcelog --ascii' 26.767371] [Hardware Error]: CPU 1: Machine Check Exception: 4 Bank 1: b200000000000175 26.767379] [Hardware Error]: TSC 1bf231e65f 26.767386] [Hardware Error]: PROCESSOR 0:6f6 TIME 1349017951 SOCKET 0 APIC 1 microcode 44 26.767395] [Hardware Error]: Run the above through 'mcelog --ascii' 26.767403] [Hardware Error]: CPU 1: Machine Check Exception: 4 Bank 5: b200003008000e0f 26.767413] [Hardware Error]: TSC 1bf231e65f 26.767421] [Hardware Error]: PROCESSOR 0:6f6 TIME 1349017951 SOCKET 0 APIC 1 microcode 44 26.767429] [Hardware Error]: Run the above through 'mcelog --ascii' 26.767437] [Hardware Error]: CPU 0: Machine Check Exception: 5 Bank 5: b200001806000e0f 26.767447] [Hardware Error]: RIP |INEXACT| 60:<00000000c1018b5c> {mwait_idle+0x7c/0x1d0} 26.767464] [Hardware Error]: TSC 1bf231e674 26.767471] [Hardware Error]: PROCESSOR 0:6f6 TIME 1349017951 SOCKET 0 APIC 0 microcode 44 26.767480] [Hardware Error]: Run the above through 'mcelog --ascii' 26.767487] [Hardware Error]: Machine check: Processor context corrupt 26.767495] Kernel panic - not syncing: Fatal Machine check 26.767505] Pid: 579, comm: debconf-communi Tainted: G M 3.2.0.29-generic-pae #46-Ubuntu 26.767515] Call Trace: 26.767525] [<c158f812>] ? printk+0x2d/0x2f 26.767534] [<c158f6e0>] panic+0x5c/0x161 26.767542] [<c10247ef>] mce_panic.part.14+0x13f/0x170 26.767551] [<c1024872>] mce_panic+0x52/0x90 26.767558] [<c1024a18>] mce_reign+0x168/0x170 26.767565] [<c1024bb5>] mce_end+0x105/0x110 26.767572] [<c10252db>] do_machine_check+0x32b/0x4f0 26.767581] [<c1024fb0>] ? mce_log+0x120/0x120 26.767590] [<c15a5e47>] error_code+0x67/0x6c 26.767602] panic occurred, switching back to text console 26.768498] Rebooting in 30 seconds.. For information, I have also tried earlier Arch Linux. I can install it, but when I try to install a window manager (LXDE) again I got similar errors. Fedora also crashes when installing and also Mandriva did not work for me. Therefore I think something deep in the machine might be wrong. But as stated above I can (clean) install 8.04 and also 9.10 can be installed without problems. Also updates for 8.04 can be installed. My machine is dual boot with XP next to it on a different partition. My HW: Memory : 2.0 GiB; Processor 0: Intel(R) Core(TM)2 CPU 6320 @ 1.86GHz; Processor 1: Intel(R) Core(TM)2 CPU 6320 @ 1.86GHz; How can I install Ubuntu 12.04? Last option would be to completely format my machine and install everything from scratch, but even I am not sure if that would solve it in the end. Can anybody help me out?

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2012 Oracle Fusion Innovation Awards - Part 2

- by Michelle Kimihira

Author: Moazzam Chaudry Continuing from Friday's blog on 2012 Oracle Fusion Innovation Awards, this blog (Part 2) will provide more details around the customers. It was a tremendous honor to be in single room of winners. We only wish we could have had more time to share stories from all the winners. We received great insight from all the innovative solutions that our customers deploy and would like to share them broadly, so that others can benefit from best practices. There was a customer panel session joined by Ingersoll Rand, Nike and Motability and here is what was discussed: Barry Bonar, Enterprise Architect from Ingersoll Rand shared details around their solution, comprised of Oracle Exalogic, Oracle WebLogic Server and Oracle SOA Suite. This combined solutoin enabled their business transformation to increase decision-making, speed and efficiency, resulting in 40% reduced IT spend, 41X Faster response time and huge cost savings. Ashok Balakrishnan, Architect from Nike shared how they leveraged Oracle Coherence to analyze their digital "footprint" of activities. This helps them compete, collaborate and compare athletic data over time. Lastly, Ashley Doodly, Head of IT from Motability shared details around their solution compromised of Oracle SOA Suite, Service Bus, ADF, Coherence, BO and E-Business Suite. This solution helped Motability achieve 100% ROI within the first few months, performance in seconds vs. 10's of minutes and tremendous improvement in throughput that increased up to 50%. This year's winners by category are: Oracle Exalogic Customer Results using Fusion Middleware Netshoes ATG on Exalogic: 6X Reduced H/W foot print, 6.2X increased throughput and 3 weeks time to market Claro Part of America Movil, running mission critical Java Application on Exalogic with 35X Faster Java response time, 5X Throughput Underwriters Laboratories Exalogic as an Apps Consolidation platform to power tremendous growth Ingersoll Rand EBS on Exalogic: Up to 40% Reduction in overall IT budget, 3x reduced foot print Oracle Cloud Application Foundation Customer Results using Fusion Middleware Mazda Motor Corporation Tuxedo ART Batch runtime environment to migrate their batch apps on new open environment and reduce main frame cost. HOTELBEDS Technology Open Source to WebLogic transformation Globalia Corporation Introduced Oracle Coherence to fully reengineer DTH system and provide multiple business and technical benefits Nike Nike+, digital sports platform, has 8M users and is expecting an 5X increase in users, many of who will carry multiple devices that frequently sync data with the Digital Sport platform Comcast Corporation The solution is expected to increase availability, continuity, performance, and simplify and make the code at the application layer more flexible. Oracle SOA and Oracle BPM Customer Results using Fusion Middleware NTT Docomo Network traffic solution based on Oracle event processing and coherence - massive in scale: 12M users (50M in future) - 800,000 events/sec. Schneider National, Inc. SOA/B2B/ADF/Data Integration to orchestrate key order processes across Siebel, OTM & EBS. Platform runs 60M trans/day and 50 million composite SOA instances per day across 10G and 11G Amadeus Oracle BPM solution: Business Rules and processes vary across local (80), regional (~10) and corporate approval process. Up to 10 levels of approval. Plans to deploy across 20+ markets Navitar SOA solution integrates a fully non-Oracle legacy application/ERP environment using Oracle’s SOA Suite and Oracle AIA Foundation Pack. Motability Uses SOA Suite to synchronize data across the systems and to manage the vehicle remarketing process Oracle WebCenter Customer Results using Fusion Middleware News Limited Single platform running websites for 50% of Australia's newspapers University of Louisville “Facebook for Medicine”: Oracle Webcenter platform and Oracle BIEE to analyze patient test data and uncover potential health issues. Expecting annualized ROI of 277% China Mobile Jiangsu Company portal (25k users) to drive collaboration & productivity Life Technologies Portal for remotely monitoring & repairing biotech instruments LA Dept. of Water & Power Oracle WebCenter Portal to power ladwp.com on desktop and mobile for 1.6million users Oracle Identity Management Customer Results using Fusion Middleware Education Testing Service Identity Management platform for provisioning & SSO of 6 million GRE, GMAT, TOEFL customers Avea Oracle Identity Manager allowing call center personnel to quickly change Identity Profile to handle varying call loads based on a user self service interface. Decreased Admin Cost by 30% Oracle Data Integration Customer Results using Fusion Middleware Raymond James Near real-time integration for improved systems (throughput & performance) and enhanced operational flexibility in a 24 X 7 environment Wm Morrison Supermarkets Electronic Point of Sale integration handling over 80 million transactions a day in near real time (15 min intervals) Oracle Application Development Framework and Oracle Fusion Development Customer Results using Fusion Middleware Qualcomm Incorporated Solution providing immediate business value enabling a self-service model necessary for growing the new customer base, an increase in customer satisfaction, reduced “time-to-deliver” Micros Systems, Inc. ADF, SOA Suite, WebCenter enables services that include managing distribution of hotel rooms availability and rates to channels such as Hotel Web-site, Expedia, etc. Marfin Egnatia Bank A new web 2.0 UI provides a much richer experience through the ADF solution with the end result being one of boosting end-user productivity Business Analytics (Oracle BI, Oracle EPM, Oracle Exalytics) Customer Results using Fusion Middleware INC Research Self-service customer portal delivering 5–10% of the overall revenue - expected to grow fast with the BI solution Experian Reduction in Time to Complete the Financial Close Process Hologic Inc Solution, saving months of decision-making uncertainty! We look forward to seeing many more innovative nominations. The nominatation process for 2013 begins in April 2013. Additional Information: Blog: Oracle WebCenter Award Winners Blog: Oracle Identity Management Winners Blog: Oracle Exalogic Winners Blog: SOA, BPM and Data Integration will be will feature award winners in its respective areas this week Subscribe to our regular Fusion Middleware Newsletter Follow us on Twitter and Facebook

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How John Got 15x Improvement Without Really Trying

- by rchrd

The following article was published on a Sun Microsystems website a number of years ago by John Feo. It is still useful and worth preserving. So I'm republishing it here. How I Got 15x Improvement Without Really Trying John Feo, Sun Microsystems Taking ten "personal" program codes used in scientific and engineering research, the author was able to get from 2 to 15 times performance improvement easily by applying some simple general optimization techniques. Introduction Scientific research based on computer simulation depends on the simulation for advancement. The research can advance only as fast as the computational codes can execute. The codes' efficiency determines both the rate and quality of results. In the same amount of time, a faster program can generate more results and can carry out a more detailed simulation of physical phenomena than a slower program. Highly optimized programs help science advance quickly and insure that monies supporting scientific research are used as effectively as possible. Scientific computer codes divide into three broad categories: ISV, community, and personal. ISV codes are large, mature production codes developed and sold commercially. The codes improve slowly over time both in methods and capabilities, and they are well tuned for most vendor platforms. Since the codes are mature and complex, there are few opportunities to improve their performance solely through code optimization. Improvements of 10% to 15% are typical. Examples of ISV codes are DYNA3D, Gaussian, and Nastran. Community codes are non-commercial production codes used by a particular research field. Generally, they are developed and distributed by a single academic or research institution with assistance from the community. Most users just run the codes, but some develop new methods and extensions that feed back into the general release. The codes are available on most vendor platforms. Since these codes are younger than ISV codes, there are more opportunities to optimize the source code. Improvements of 50% are not unusual. Examples of community codes are AMBER, CHARM, BLAST, and FASTA. Personal codes are those written by single users or small research groups for their own use. These codes are not distributed, but may be passed from professor-to-student or student-to-student over several years. They form the primordial ocean of applications from which community and ISV codes emerge. Government research grants pay for the development of most personal codes. This paper reports on the nature and performance of this class of codes. Over the last year, I have looked at over two dozen personal codes from more than a dozen research institutions. The codes cover a variety of scientific fields, including astronomy, atmospheric sciences, bioinformatics, biology, chemistry, geology, and physics. The sources range from a few hundred lines to more than ten thousand lines, and are written in Fortran, Fortran 90, C, and C++. For the most part, the codes are modular, documented, and written in a clear, straightforward manner. They do not use complex language features, advanced data structures, programming tricks, or libraries. I had little trouble understanding what the codes did or how data structures were used. Most came with a makefile. Surprisingly, only one of the applications is parallel. All developers have access to parallel machines, so availability is not an issue. Several tried to parallelize their applications, but stopped after encountering difficulties. Lack of education and a perception that parallelism is difficult prevented most from trying. I parallelized several of the codes using OpenMP, and did not judge any of the codes as difficult to parallelize. Even more surprising than the lack of parallelism is the inefficiency of the codes. I was able to get large improvements in performance in a matter of a few days applying simple optimization techniques. Table 1 lists ten representative codes [names and affiliation are omitted to preserve anonymity]. Improvements on one processor range from 2x to 15.5x with a simple average of 4.75x. I did not use sophisticated performance tools or drill deep into the program's execution character as one would do when tuning ISV or community codes. Using only a profiler and source line timers, I identified inefficient sections of code and improved their performance by inspection. The changes were at a high level. I am sure there is another factor of 2 or 3 in each code, and more if the codes are parallelized. The study’s results show that personal scientific codes are running many times slower than they should and that the problem is pervasive. Computational scientists are not sloppy programmers; however, few are trained in the art of computer programming or code optimization. I found that most have a working knowledge of some programming language and standard software engineering practices; but they do not know, or think about, how to make their programs run faster. They simply do not know the standard techniques used to make codes run faster. In fact, they do not even perceive that such techniques exist. The case studies described in this paper show that applying simple, well known techniques can significantly increase the performance of personal codes. It is important that the scientific community and the Government agencies that support scientific research find ways to better educate academic scientific programmers. The inefficiency of their codes is so bad that it is retarding both the quality and progress of scientific research. # cacheperformance redundantoperations loopstructures performanceimprovement 1 x x 15.5 2 x 2.8 3 x x 2.5 4 x 2.1 5 x x 2.0 6 x 5.0 7 x 5.8 8 x 6.3 9 2.2 10 x x 3.3 Table 1 — Area of improvement and performance gains of 10 codes The remainder of the paper is organized as follows: sections 2, 3, and 4 discuss the three most common sources of inefficiencies in the codes studied. These are cache performance, redundant operations, and loop structures. Each section includes several examples. The last section summaries the work and suggests a possible solution to the issues raised. Optimizing cache performance Commodity microprocessor systems use caches to increase memory bandwidth and reduce memory latencies. Typical latencies from processor to L1, L2, local, and remote memory are 3, 10, 50, and 200 cycles, respectively. Moreover, bandwidth falls off dramatically as memory distances increase. Programs that do not use cache effectively run many times slower than programs that do. When optimizing for cache, the biggest performance gains are achieved by accessing data in cache order and reusing data to amortize the overhead of cache misses. Secondary considerations are prefetching, associativity, and replacement; however, the understanding and analysis required to optimize for the latter are probably beyond the capabilities of the non-expert. Much can be gained simply by accessing data in the correct order and maximizing data reuse. 6 out of the 10 codes studied here benefited from such high level optimizations. Array Accesses The most important cache optimization is the most basic: accessing Fortran array elements in column order and C array elements in row order. Four of the ten codes—1, 2, 4, and 10—got it wrong. Compilers will restructure nested loops to optimize cache performance, but may not do so if the loop structure is too complex, or the loop body includes conditionals, complex addressing, or function calls. In code 1, the compiler failed to invert a key loop because of complex addressing do I = 0, 1010, delta_x IM = I - delta_x IP = I + delta_x do J = 5, 995, delta_x JM = J - delta_x JP = J + delta_x T1 = CA1(IP, J) + CA1(I, JP) T2 = CA1(IM, J) + CA1(I, JM) S1 = T1 + T2 - 4 * CA1(I, J) CA(I, J) = CA1(I, J) + D * S1 end do end do In code 2, the culprit is conditionals do I = 1, N do J = 1, N If (IFLAG(I,J) .EQ. 0) then T1 = Value(I, J-1) T2 = Value(I-1, J) T3 = Value(I, J) T4 = Value(I+1, J) T5 = Value(I, J+1) Value(I,J) = 0.25 * (T1 + T2 + T5 + T4) Delta = ABS(T3 - Value(I,J)) If (Delta .GT. MaxDelta) MaxDelta = Delta endif enddo enddo I fixed both programs by inverting the loops by hand. Code 10 has three-dimensional arrays and triply nested loops. The structure of the most computationally intensive loops is too complex to invert automatically or by hand. The only practical solution is to transpose the arrays so that the dimension accessed by the innermost loop is in cache order. The arrays can be transposed at construction or prior to entering a computationally intensive section of code. The former requires all array references to be modified, while the latter is cost effective only if the cost of the transpose is amortized over many accesses. I used the second approach to optimize code 10. Code 5 has four-dimensional arrays and loops are nested four deep. For all of the reasons cited above the compiler is not able to restructure three key loops. Assume C arrays and let the four dimensions of the arrays be i, j, k, and l. In the original code, the index structure of the three loops is L1: for i L2: for i L3: for i for l for l for j for k for j for k for j for k for l So only L3 accesses array elements in cache order. L1 is a very complex loop—much too complex to invert. I brought the loop into cache alignment by transposing the second and fourth dimensions of the arrays. Since the code uses a macro to compute all array indexes, I effected the transpose at construction and changed the macro appropriately. The dimensions of the new arrays are now: i, l, k, and j. L3 is a simple loop and easily inverted. L2 has a loop-carried scalar dependence in k. By promoting the scalar name that carries the dependence to an array, I was able to invert the third and fourth subloops aligning the loop with cache. Code 5 is by far the most difficult of the four codes to optimize for array accesses; but the knowledge required to fix the problems is no more than that required for the other codes. I would judge this code at the limits of, but not beyond, the capabilities of appropriately trained computational scientists. Array Strides When a cache miss occurs, a line (64 bytes) rather than just one word is loaded into the cache. If data is accessed stride 1, than the cost of the miss is amortized over 8 words. Any stride other than one reduces the cost savings. Two of the ten codes studied suffered from non-unit strides. The codes represent two important classes of "strided" codes. Code 1 employs a multi-grid algorithm to reduce time to convergence. The grids are every tenth, fifth, second, and unit element. Since time to convergence is inversely proportional to the distance between elements, coarse grids converge quickly providing good starting values for finer grids. The better starting values further reduce the time to convergence. The downside is that grids of every nth element, n > 1, introduce non-unit strides into the computation. In the original code, much of the savings of the multi-grid algorithm were lost due to this problem. I eliminated the problem by compressing (copying) coarse grids into continuous memory, and rewriting the computation as a function of the compressed grid. On convergence, I copied the final values of the compressed grid back to the original grid. The savings gained from unit stride access of the compressed grid more than paid for the cost of copying. Using compressed grids, the loop from code 1 included in the previous section becomes do j = 1, GZ do i = 1, GZ T1 = CA(i+0, j-1) + CA(i-1, j+0) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) S1 = T1 + T4 - 4 * CA1(i+0, j+0) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 enddo enddo where CA and CA1 are compressed arrays of size GZ. Code 7 traverses a list of objects selecting objects for later processing. The labels of the selected objects are stored in an array. The selection step has unit stride, but the processing steps have irregular stride. A fix is to save the parameters of the selected objects in temporary arrays as they are selected, and pass the temporary arrays to the processing functions. The fix is practical if the same parameters are used in selection as in processing, or if processing comprises a series of distinct steps which use overlapping subsets of the parameters. Both conditions are true for code 7, so I achieved significant improvement by copying parameters to temporary arrays during selection. Data reuse In the previous sections, we optimized for spatial locality. It is also important to optimize for temporal locality. Once read, a datum should be used as much as possible before it is forced from cache. Loop fusion and loop unrolling are two techniques that increase temporal locality. Unfortunately, both techniques increase register pressure—as loop bodies become larger, the number of registers required to hold temporary values grows. Once register spilling occurs, any gains evaporate quickly. For multiprocessors with small register sets or small caches, the sweet spot can be very small. In the ten codes presented here, I found no opportunities for loop fusion and only two opportunities for loop unrolling (codes 1 and 3). In code 1, unrolling the outer and inner loop one iteration increases the number of result values computed by the loop body from 1 to 4, do J = 1, GZ-2, 2 do I = 1, GZ-2, 2 T1 = CA1(i+0, j-1) + CA1(i-1, j+0) T2 = CA1(i+1, j-1) + CA1(i+0, j+0) T3 = CA1(i+0, j+0) + CA1(i-1, j+1) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) T5 = CA1(i+2, j+0) + CA1(i+1, j+1) T6 = CA1(i+1, j+1) + CA1(i+0, j+2) T7 = CA1(i+2, j+1) + CA1(i+1, j+2) S1 = T1 + T4 - 4 * CA1(i+0, j+0) S2 = T2 + T5 - 4 * CA1(i+1, j+0) S3 = T3 + T6 - 4 * CA1(i+0, j+1) S4 = T4 + T7 - 4 * CA1(i+1, j+1) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 CA(i+1, j+0) = CA1(i+1, j+0) + DD * S2 CA(i+0, j+1) = CA1(i+0, j+1) + DD * S3 CA(i+1, j+1) = CA1(i+1, j+1) + DD * S4 enddo enddo The loop body executes 12 reads, whereas as the rolled loop shown in the previous section executes 20 reads to compute the same four values. In code 3, two loops are unrolled 8 times and one loop is unrolled 4 times. Here is the before for (k = 0; k < NK[u]; k++) { sum = 0.0; for (y = 0; y < NY; y++) { sum += W[y][u][k] * delta[y]; } backprop[i++]=sum; } and after code for (k = 0; k < KK - 8; k+=8) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (y = 0; y < NY; y++) { sum0 += W[y][0][k+0] * delta[y]; sum1 += W[y][0][k+1] * delta[y]; sum2 += W[y][0][k+2] * delta[y]; sum3 += W[y][0][k+3] * delta[y]; sum4 += W[y][0][k+4] * delta[y]; sum5 += W[y][0][k+5] * delta[y]; sum6 += W[y][0][k+6] * delta[y]; sum7 += W[y][0][k+7] * delta[y]; } backprop[k+0] = sum0; backprop[k+1] = sum1; backprop[k+2] = sum2; backprop[k+3] = sum3; backprop[k+4] = sum4; backprop[k+5] = sum5; backprop[k+6] = sum6; backprop[k+7] = sum7; } for one of the loops unrolled 8 times. Optimizing for temporal locality is the most difficult optimization considered in this paper. The concepts are not difficult, but the sweet spot is small. Identifying where the program can benefit from loop unrolling or loop fusion is not trivial. Moreover, it takes some effort to get it right. Still, educating scientific programmers about temporal locality and teaching them how to optimize for it will pay dividends. Reducing instruction count Execution time is a function of instruction count. Reduce the count and you usually reduce the time. The best solution is to use a more efficient algorithm; that is, an algorithm whose order of complexity is smaller, that converges quicker, or is more accurate. Optimizing source code without changing the algorithm yields smaller, but still significant, gains. This paper considers only the latter because the intent is to study how much better codes can run if written by programmers schooled in basic code optimization techniques. The ten codes studied benefited from three types of "instruction reducing" optimizations. The two most prevalent were hoisting invariant memory and data operations out of inner loops. The third was eliminating unnecessary data copying. The nature of these inefficiencies is language dependent. Memory operations The semantics of C make it difficult for the compiler to determine all the invariant memory operations in a loop. The problem is particularly acute for loops in functions since the compiler may not know the values of the function's parameters at every call site when compiling the function. Most compilers support pragmas to help resolve ambiguities; however, these pragmas are not comprehensive and there is no standard syntax. To guarantee that invariant memory operations are not executed repetitively, the user has little choice but to hoist the operations by hand. The problem is not as severe in Fortran programs because in the absence of equivalence statements, it is a violation of the language's semantics for two names to share memory. Codes 3 and 5 are C programs. In both cases, the compiler did not hoist all invariant memory operations from inner loops. Consider the following loop from code 3 for (y = 0; y < NY; y++) { i = 0; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += delta[y] * I1[i++]; } } } Since dW[y][u] can point to the same memory space as delta for one or more values of y and u, assignment to dW[y][u][k] may change the value of delta[y]. In reality, dW and delta do not overlap in memory, so I rewrote the loop as for (y = 0; y < NY; y++) { i = 0; Dy = delta[y]; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += Dy * I1[i++]; } } } Failure to hoist invariant memory operations may be due to complex address calculations. If the compiler can not determine that the address calculation is invariant, then it can hoist neither the calculation nor the associated memory operations. As noted above, code 5 uses a macro to address four-dimensional arrays #define MAT4D(a,q,i,j,k) (double *)((a)->data + (q)*(a)->strides[0] + (i)*(a)->strides[3] + (j)*(a)->strides[2] + (k)*(a)->strides[1]) The macro is too complex for the compiler to understand and so, it does not identify any subexpressions as loop invariant. The simplest way to eliminate the address calculation from the innermost loop (over i) is to define a0 = MAT4D(a,q,0,j,k) before the loop and then replace all instances of *MAT4D(a,q,i,j,k) in the loop with a0[i] A similar problem appears in code 6, a Fortran program. The key loop in this program is do n1 = 1, nh nx1 = (n1 - 1) / nz + 1 nz1 = n1 - nz * (nx1 - 1) do n2 = 1, nh nx2 = (n2 - 1) / nz + 1 nz2 = n2 - nz * (nx2 - 1) ndx = nx2 - nx1 ndy = nz2 - nz1 gxx = grn(1,ndx,ndy) gyy = grn(2,ndx,ndy) gxy = grn(3,ndx,ndy) balance(n1,1) = balance(n1,1) + (force(n2,1) * gxx + force(n2,2) * gxy) * h1 balance(n1,2) = balance(n1,2) + (force(n2,1) * gxy + force(n2,2) * gyy)*h1 end do end do The programmer has written this loop well—there are no loop invariant operations with respect to n1 and n2. However, the loop resides within an iterative loop over time and the index calculations are independent with respect to time. Trading space for time, I precomputed the index values prior to the entering the time loop and stored the values in two arrays. I then replaced the index calculations with reads of the arrays. Data operations Ways to reduce data operations can appear in many forms. Implementing a more efficient algorithm produces the biggest gains. The closest I came to an algorithm change was in code 4. This code computes the inner product of K-vectors A(i) and B(j), 0 = i < N, 0 = j < M, for most values of i and j. Since the program computes most of the NM possible inner products, it is more efficient to compute all the inner products in one triply-nested loop rather than one at a time when needed. The savings accrue from reading A(i) once for all B(j) vectors and from loop unrolling. for (i = 0; i < N; i+=8) { for (j = 0; j < M; j++) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (k = 0; k < K; k++) { sum0 += A[i+0][k] * B[j][k]; sum1 += A[i+1][k] * B[j][k]; sum2 += A[i+2][k] * B[j][k]; sum3 += A[i+3][k] * B[j][k]; sum4 += A[i+4][k] * B[j][k]; sum5 += A[i+5][k] * B[j][k]; sum6 += A[i+6][k] * B[j][k]; sum7 += A[i+7][k] * B[j][k]; } C[i+0][j] = sum0; C[i+1][j] = sum1; C[i+2][j] = sum2; C[i+3][j] = sum3; C[i+4][j] = sum4; C[i+5][j] = sum5; C[i+6][j] = sum6; C[i+7][j] = sum7; }} This change requires knowledge of a typical run; i.e., that most inner products are computed. The reasons for the change, however, derive from basic optimization concepts. It is the type of change easily made at development time by a knowledgeable programmer. In code 5, we have the data version of the index optimization in code 6. Here a very expensive computation is a function of the loop indices and so cannot be hoisted out of the loop; however, the computation is invariant with respect to an outer iterative loop over time. We can compute its value for each iteration of the computation loop prior to entering the time loop and save the values in an array. The increase in memory required to store the values is small in comparison to the large savings in time. The main loop in Code 8 is doubly nested. The inner loop includes a series of guarded computations; some are a function of the inner loop index but not the outer loop index while others are a function of the outer loop index but not the inner loop index for (j = 0; j < N; j++) { for (i = 0; i < M; i++) { r = i * hrmax; R = A[j]; temp = (PRM[3] == 0.0) ? 1.0 : pow(r, PRM[3]); high = temp * kcoeff * B[j] * PRM[2] * PRM[4]; low = high * PRM[6] * PRM[6] / (1.0 + pow(PRM[4] * PRM[6], 2.0)); kap = (R > PRM[6]) ? high * R * R / (1.0 + pow(PRM[4]*r, 2.0) : low * pow(R/PRM[6], PRM[5]); < rest of loop omitted > }} Note that the value of temp is invariant to j. Thus, we can hoist the computation for temp out of the loop and save its values in an array. for (i = 0; i < M; i++) { r = i * hrmax; TEMP[i] = pow(r, PRM[3]); } [N.B. – the case for PRM[3] = 0 is omitted and will be reintroduced later.] We now hoist out of the inner loop the computations invariant to i. Since the conditional guarding the value of kap is invariant to i, it behooves us to hoist the computation out of the inner loop, thereby executing the guard once rather than M times. The final version of the code is for (j = 0; j < N; j++) { R = rig[j] / 1000.; tmp1 = kcoeff * par[2] * beta[j] * par[4]; tmp2 = 1.0 + (par[4] * par[4] * par[6] * par[6]); tmp3 = 1.0 + (par[4] * par[4] * R * R); tmp4 = par[6] * par[6] / tmp2; tmp5 = R * R / tmp3; tmp6 = pow(R / par[6], par[5]); if ((par[3] == 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp5; } else if ((par[3] == 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp4 * tmp6; } else if ((par[3] != 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp5; } else if ((par[3] != 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp4 * tmp6; } for (i = 0; i < M; i++) { kap = KAP[i]; r = i * hrmax; < rest of loop omitted > } } Maybe not the prettiest piece of code, but certainly much more efficient than the original loop, Copy operations Several programs unnecessarily copy data from one data structure to another. This problem occurs in both Fortran and C programs, although it manifests itself differently in the two languages. Code 1 declares two arrays—one for old values and one for new values. At the end of each iteration, the array of new values is copied to the array of old values to reset the data structures for the next iteration. This problem occurs in Fortran programs not included in this study and in both Fortran 77 and Fortran 90 code. Introducing pointers to the arrays and swapping pointer values is an obvious way to eliminate the copying; but pointers is not a feature that many Fortran programmers know well or are comfortable using. An easy solution not involving pointers is to extend the dimension of the value array by 1 and use the last dimension to differentiate between arrays at different times. For example, if the data space is N x N, declare the array (N, N, 2). Then store the problem’s initial values in (_, _, 2) and define the scalar names new = 2 and old = 1. At the start of each iteration, swap old and new to reset the arrays. The old–new copy problem did not appear in any C program. In programs that had new and old values, the code swapped pointers to reset data structures. Where unnecessary coping did occur is in structure assignment and parameter passing. Structures in C are handled much like scalars. Assignment causes the data space of the right-hand name to be copied to the data space of the left-hand name. Similarly, when a structure is passed to a function, the data space of the actual parameter is copied to the data space of the formal parameter. If the structure is large and the assignment or function call is in an inner loop, then copying costs can grow quite large. While none of the ten programs considered here manifested this problem, it did occur in programs not included in the study. A simple fix is always to refer to structures via pointers. Optimizing loop structures Since scientific programs spend almost all their time in loops, efficient loops are the key to good performance. Conditionals, function calls, little instruction level parallelism, and large numbers of temporary values make it difficult for the compiler to generate tightly packed, highly efficient code. Conditionals and function calls introduce jumps that disrupt code flow. Users should eliminate or isolate conditionls to their own loops as much as possible. Often logical expressions can be substituted for if-then-else statements. For example, code 2 includes the following snippet MaxDelta = 0.0 do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) if (Delta > MaxDelta) MaxDelta = Delta enddo enddo if (MaxDelta .gt. 0.001) goto 200 Since the only use of MaxDelta is to control the jump to 200 and all that matters is whether or not it is greater than 0.001, I made MaxDelta a boolean and rewrote the snippet as MaxDelta = .false. do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) MaxDelta = MaxDelta .or. (Delta .gt. 0.001) enddo enddo if (MaxDelta) goto 200 thereby, eliminating the conditional expression from the inner loop. A microprocessor can execute many instructions per instruction cycle. Typically, it can execute one or more memory, floating point, integer, and jump operations. To be executed simultaneously, the operations must be independent. Thick loops tend to have more instruction level parallelism than thin loops. Moreover, they reduce memory traffice by maximizing data reuse. Loop unrolling and loop fusion are two techniques to increase the size of loop bodies. Several of the codes studied benefitted from loop unrolling, but none benefitted from loop fusion. This observation is not too surpising since it is the general tendency of programmers to write thick loops. As loops become thicker, the number of temporary values grows, increasing register pressure. If registers spill, then memory traffic increases and code flow is disrupted. A thick loop with many temporary values may execute slower than an equivalent series of thin loops. The biggest gain will be achieved if the thick loop can be split into a series of independent loops eliminating the need to write and read temporary arrays. I found such an occasion in code 10 where I split the loop do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do into two disjoint loops do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) end do end do do i = 1, n do j = 1, m C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do Conclusions Over the course of the last year, I have had the opportunity to work with over two dozen academic scientific programmers at leading research universities. Their research interests span a broad range of scientific fields. Except for two programs that relied almost exclusively on library routines (matrix multiply and fast Fourier transform), I was able to improve significantly the single processor performance of all codes. Improvements range from 2x to 15.5x with a simple average of 4.75x. Changes to the source code were at a very high level. I did not use sophisticated techniques or programming tools to discover inefficiencies or effect the changes. Only one code was parallel despite the availability of parallel systems to all developers. Clearly, we have a problem—personal scientific research codes are highly inefficient and not running parallel. The developers are unaware of simple optimization techniques to make programs run faster. They lack education in the art of code optimization and parallel programming. I do not believe we can fix the problem by publishing additional books or training manuals. To date, the developers in questions have not studied the books or manual available, and are unlikely to do so in the future. Short courses are a possible solution, but I believe they are too concentrated to be much use. The general concepts can be taught in a three or four day course, but that is not enough time for students to practice what they learn and acquire the experience to apply and extend the concepts to their codes. Practice is the key to becoming proficient at optimization. I recommend that graduate students be required to take a semester length course in optimization and parallel programming. We would never give someone access to state-of-the-art scientific equipment costing hundreds of thousands of dollars without first requiring them to demonstrate that they know how to use the equipment. Yet the criterion for time on state-of-the-art supercomputers is at most an interesting project. Requestors are never asked to demonstrate that they know how to use the system, or can use the system effectively. A semester course would teach them the required skills. Government agencies that fund academic scientific research pay for most of the computer systems supporting scientific research as well as the development of most personal scientific codes. These agencies should require graduate schools to offer a course in optimization and parallel programming as a requirement for funding. About the Author John Feo received his Ph.D. in Computer Science from The University of Texas at Austin in 1986. After graduate school, Dr. Feo worked at Lawrence Livermore National Laboratory where he was the Group Leader of the Computer Research Group and principal investigator of the Sisal Language Project. In 1997, Dr. Feo joined Tera Computer Company where he was project manager for the MTA, and oversaw the programming and evaluation of the MTA at the San Diego Supercomputer Center. In 2000, Dr. Feo joined Sun Microsystems as an HPC application specialist. He works with university research groups to optimize and parallelize scientific codes. Dr. Feo has published over two dozen research articles in the areas of parallel parallel programming, parallel programming languages, and application performance.

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How to convert my backup.cmd into something I can run in Linux?

- by blade19899

Back in the day when i was using windows(and a noob at everything IT) i liked batch scripting so much that i wrote a lot of them and one i am pretty proud of that is my backup.cmd(see below). I am pretty basic with the linux bash sudo/apt-get/sl/ls/locate/updatedb/etc... I don't really know the full power of the terminal. If you see the code below can i get it to work under (Ubuntu)linux :) by rewriting some of the windows code with the linux equivalent (btw:this works under xp/vista/7 | dutch/english) @echo off title back it up :home cls echo ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» echo º º echo º typ A/B for the options º echo º º echo ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ¹ echo º º echo º "A"=backup options º echo º º echo º "B"=HARDDISK Options º echo º º echo º º echo ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍŒ set /p selection=Choose: Goto %selection% :A cls echo ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» echo º º echo º typ 1 to start that backup º echo º º echo ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ¹ echo º º echo º "A"=backup options º echo º È1=Documents,Pictures,Music,Videos,Downloads º echo º º echo º "B"=HARDDISK Options º echo º º echo ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍŒ set /p selection=Choose: Goto %selection% :B cls echo ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» echo º º echo º typ HD to start the disk check º echo º º echo ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ¹ echo º º echo º "A"=backup options º echo º º echo º "B"=HARDDISK Options º echo º ÈHD=find and repair bad sectors º echo º º echo ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍŒ set /p selection=Choose: Goto %selection% :1 cls if exist "%userprofile%\desktop" (set desk=desktop) else (set desk=Bureaublad) if exist "%userprofile%\documents" (set docs=documents) else (set docs=mijn documenten) if exist "%userprofile%\pictures" (set pics=pictures) else (echo cant find %userprofile%\pictures) if exist "%userprofile%\music" (set mus=music) else (echo cant find %userprofile%\music) if exist "%userprofile%\Videos" (set vids=videos) else (echo cant find %userprofile%\videos) if exist "%userprofile%\Downloads" (set down=downloads) else (echo cant find %userprofile%\Downloads) cls echo. examples (D:\) (D:\Backup) (D:\Backup\18-4-2011) echo. echo. if there is no "D:\backup" folder then the folder will be created echo. set drive= set /p drive=storage: echo start>>backup.log echo Name:%username%>>backup.log echo Date:%date%>>backup.log echo Time:%time%>>backup.log echo ========================================%docs%===========================================>>backup.log echo %docs% echo Source:"%userprofile%\%docs%" echo Destination:"%drive%\%username%\%docs%" echo %time%>>backup.log xcopy "%userprofile%\%docs%" "%drive%\%username%\%docs%" /E /I>>Backup.log echo 20%% cls echo ========================================"%pics%"=========================================>>backup.log echo "%pics%" echo Source:"%userprofile%\%pics%" echo Destination:"%drive%\%username%\%pics%" echo %time%>>backup.log xcopy "%userprofile%\%pics%" "%drive%\%username%\%pics%" /E /I>>Backup.log echo 40%% cls echo ========================================"%mus%"=========================================>>backup.log echo "%mus%" echo Source:"%userprofile%\%mus%" echo Destination:"%drive%\%username%\%mus%" echo %time%>>backup.log xcopy "%userprofile%\%mus%" "%drive%\%username%\%mus%" /E /I>>Backup.log echo 60%% cls echo ========================================"%vids%"========================================>>backup.log echo %vids% echo Source:"%userprofile%\%vids%" echo Destination:"%drive%\%username%\%vids%" echo %time%>>backup.log xcopy "%userprofile%\%vids%" "%drive%\%username%\%vids%" /E /I>>Backup.log echo 80%% cls echo ========================================"%down%"========================================>>backup.log echo "%down%" echo Source:"%userprofile%\%down%" echo Destination:"%drive%\%username%\%down%" echo %time%>>backup.log xcopy "%userprofile%\%down%" "%drive%\%username%\%down%" /E /I>>Backup.log echo end>>backup.log echo %username% %date% %time%>>backup.log echo 100%% cls echo backup Compleet copy "backup.log" "%drive%\%username%" del "backup.log" pushd "%drive%\%username%" echo close backup.log to continue with backup script "backup.log" echo press any key to retun to the main menu pause>nul goto :home :HD echo finds and repairs bad sectors echo typ in harddisk letter (C: D: E:) set HD= set /p HD=Hard Disk: chkdsk %HD% /F /R /X pause goto :home

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