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  • Access to CD/DVD Drive is Denied through Windows 7 Explorer (Permission Problem)

    - by Synetech inc.
    A while ago I started having trouble with my optical drives. Both of them keep showing up in Explorer as CD/DVD drives on boot, but as soon as I put a disc in either one, it suddenly turns into a hard-drive—“local disk” is displayed in the Type column, though the File System column remains UDF/CDFS. (I though that maybe it was a permission issue on the registry key in HKLM\System\CurrentControlSet..., but I’m not so certain because of the next test.) When I try to open a disc (of any type), I get an access denied error message. If I open an elevated command-prompt, I am able to access the files. Also, if I kill Explorer and run it from an elevated command-prompt (thus giving Explorer elevated permissions), then I can access the files from Explorer. I’ve tried uninstalling and reinstalling the devices without success. The security dialog indicates that there are none set for the drives (no owner and no permissions). I tried setting the owner, but am only able to do so if there is a disc in it (it complains if it is empty), but the settings do not stick (if I immediately open the security dialog after setting it, it is empty again). I tried setting permissions, but that gives an error. I’ve included a screencap-flowchart of the security dialog of one of the drives below. (Yes, I made sure that there are no upper- or lower-filters, and yes, I ran sfc. I also made sure that in the policy editor, “devices: restrict CD-ROM...” is not set.) Does anyone know what the owner and permissions are supposed to be for optical drives and how to reset them?

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  • Postgresql Data Aggregation over WAN Securely

    - by Zach
    Hey guys, Need some advice on how to proceed with this situation: My current scenario is that I have several postgresql (50+) boxes deployed throughout various locations and data centers and a beefy postgresql box setup at a homebase location. All of the deployed boxes have identical database layouts. I'm looking for a solution that would allow for a few things. I realize some of these options overlap and some might only contain mutually exclusive solutions. However, I'm interested to hear your thoughts :) Remotely query the deployed boxes and pull the results back to the homebase box for processing. Nightly (remote) "sync" or dump the deployed boxes' databases to a master database on the homebase box. Remotely push a table entry to all of the deployed boxes from the homebase box. Ensure security of data in transit, and remotely deployed boxes. Up to this point I've been floating on a homebrew multithreaded python/perl system that SSH's into these boxes remotely, which are ACL'ed off to the homebase server and pulls (or pushes) the raw query results over the ssh connection. I have even touched #2 (remote syncing) as I know that would get nasty really quick. I'm interested in any ideas for a more elegant solution that can scale up and stick to my FreeBSD/Linux environment.

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  • No partition on USB Flash Drive?

    - by Skytunnel
    A friend gave me a corrupted USB memory stick to try recovery data from. But I've had some unusual results, so thought I'd share to see if anyone is familiar with this problem... First off I just tried opening from my own PC. Windows prompted to Format the drive, which I of course declined Downloaded TestDisk to anaylsis the drive. And right away I noticed something strange, on the listed drives it comes up as Disk /dev/sdc - 6144 B - USB Flash Drive That's right, the first USB flash drive smaller than a floppy disk!? Moving on anyway... first anaylsis comes up with: Partition sector doesn't have the endmark 0xAA55 TestDisk's Quick Search gave no results, moved on to Deeper Search: No partition found or selected for recovery This left me stumped. I tired a couple of other programs with no success I did manage to get a backup image, but it was just as small as TestDisk indicated, so nothing of use on it After a few hours trying various suggestions from other sources, I gave in and just tried formatting the drive. But returned the message: Windows was unable to complete the format. From googling that, the suggestion was to delete the partition. But there is no partition to delete in this case. most recently I've tried formatting from cmd, and got this result: Format D: /FS:FAT32 The type of the file system is RAW The new file system is FAT32 Verifying 0M 11 bad sectors were encountered during the format. These sectors cannot be guaranteed to have been cleaned The volume is too small for FAT32 Anyone got any suggestions? UPDATE: As per suggestion from @Karen, I tried running a CLEAN from DISKPART, results as follows DiskPart has encountered an error: The request could not be preformed because of an I/O device error.

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  • PXELinux and compressed kernels/images

    - by Yvan JANSSENS
    Is it possible to boot compressed kernels with a compressed initrd with PXELinux? First, a little background: We created a custom Linux distro, for diskless OpenCL computing nodes. We want those nodes to fetch their OS from the network. Our Distro is composed out of a kernel (duh) and a large initrd which is loaded into RAM and everything is executed from there. We chose to run everything off the initrd for two reasons: NFS was not an option to serve the filesystem's extra contents Fast file access from RAM. No persistent storage needed, data and config is pulled dynamically through a SOAP service. Now our initrd is about 450M in size. At our network speeds, it takes about two to three minutes to load a single client. Will compression speed up te downloading, and if yes, which one should be used? Is LZMA supported by PXELinux, or do we need to stick to bzip2 or gzip? Because of the 2-3 minutes loading time, booting 15 nodes over the same network link takes quite a lot of time. We decided not to use hard drives or CD/DVD drives, for financial reasons (cheapest HDD @ €30 times 15 is a lot of money saved ;-) ) So, our question is: what compression options are available for this setup? And how do we do this? Thank you for your time! Yvan Janssens

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  • Windows won't boot after moving house. How do I solve this?

    - by James
    Ive just moved house and tried to set up my desktop after packing it away and now when I power it on, the BIOS boots up and no errors are found but when my computer tires to boot into Windows 7 a continuous fast beeping sound is made and a black screen is displayed. What I've done so far: Reset to UEFI defauts Played about with RAM, I had 4*4 GB sticks, I took all of them out to test for a mobo error which I have and now im only using 1 stick of 4 GB. Changed my GPU, I tok my gtx580 out and now im using the onboard Intel 3000 graphics driver, the BIOS and uefi are correctly displaying so I no longer think its a GPU based error. Ive check all of the connections and nothing seems to be loose. My HDD setup is: 2 128 GB SSD's in Raid 0 as my main C drive (possibly cause of error?) 1 1 TB Games drive 1 2 TB Data Drive Ive also got a blueray drive connected. After searching the internet im pretty much out of suggestions but im currently downloading a live CD to see if it will boot and if I can access some files on my HDD.

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  • MySQL : table organisation for very large sets with high update frequency

    - by Remiz
    I'm facing a dilemma in the choice of my MySQL schema application. So before I start here is a picture extremely simplified of my database : Schema here : http://i43.tinypic.com/2wp5lxz.png In one sentence : for each customer, the application harvest text data and attached tags to each data collected. As approximation of the usage of each table, here is what I expect : customer : ~5000, shouldn't grow fast data : 5 millions per customer, could double or triple for big customers. tag : ~1000, quite fixed size data_tag : hundred of millions per customer easily. Each data can be tagged a lot. The harvesting process is permanent, that means that around every 15 minutes new data come and are tagged, that require a very constant index refreshing. A lot of my queries are a SELECT COUNT of DATA between specific DATES and tagged with a specific TAG on a specific CUSTOMER (very rarely it will involve several customers). Here is the situation, you can imagine with this kind of volume of data I'm facing a challenge in term of data organization and indexing. Again, it's a very minimalistic and simplified version of my structure. My question is, is it better: to stick with this model and to manage crazy index optimization ? (which involves potentially having billions of rows in the data_tag table) change the schema and use one data table and one data_tag table per customer ? (which involves having 5000 tables on my database) I'm running all of this on a MySQL 5.0 dedicated server (quad-core, 8Go of ram) replicated. I only use InnoDB, I also have another server that run Sphinx. So knowing all of this, I can't wait to hear your opinion about this. Thanks.

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  • Force Installing a Radeon HD 2100 on Windows 8

    - by Click Ok
    I'm trying force installing a Radeon HD 2100 on Windows 8. I've found that link from AMD with the drivers for Windows7: http://support.amd.com/us/gpudownload/windows/legacy/Pages/legacy-radeonaiw-vista64.aspx I know too that AMD will stop support Radeon HD 400 and older: http://www.techspot.com/news/48321-amd-drops-windows-8-support-for-radeon-hd-4000-and-older.html Now, let's go to the problem. If I try install the 12.6 driver, Windows will stick with the "basic display adapter", and this is bad for 3d games like Minecraft, that runs really slow now compared with the previous Windows7 installation. Forcing install the catalyst driver can help to fix it. So, I follow that steps: Extract the Catalist Driver (C:\AMD\Support\12-6-legacy_vista_win7_64_dd_ccc_whql) Right click the "basic display adapter" on device manager, and "update driver" Search on PC I will choose the driver "With Disk" "C:\AMD\Support\12-6-legacy_vista_win7_64_dd_ccc_whql\Packages\Drivers\Display\W76A_INF" There is a big list of drivers and the nearest driver to HD 2100 is "Radeon HD 2350 Series" My questions: Why isn't "Radeon HD 2100 Series" listed? (or Where is it listed?) In theory it must be listed" The first link above show that "This article applies to the following configuration(s):" (...) "AMD Radeon HD 2000 Series" Am I doing something wrong?

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  • Advice on cloning disk

    - by hks
    I'm going to buy a second disk for backup, the same size as my laptops. I want to mount it in a casing via usb and backup an entire hdd every soemtime. That's because I want the posibility to just switch drives in case of something goes wrong. I'm using Linux and obviously the right tool seems to be dd. The thing is that my laptop drive has a speed of around 50-70 MB/s and usb 2.0 is 57 MB/s. So to copy my 250GB disk should take me more than 1 hour if I'm lucky. I can't wait this much. I want some differential backup. I read one of JWZ articles. In it he gives more details for using rsync on Mac. He writes that there is possibility of making rsync'ed disk bootable. So my question is: how to make rsync'ed hdd bootable under Linux or are there other 'quick backup' tools for Linux that would allow me to just swap drives? Or should I just stick to dd :( ?

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  • My Hard Drive isn't Working

    - by MeCB
    I never use Safely Remove Hardware with Windows XP. It has been working for me for years with my SD card, mouse, hard drive and memory stick. My hard drive has a USB cable and power cord so I can hook it up to any desktop hard drive. Now my hard drives don't like this and I did not know this till now. I am always careful and to wait till it is all finish accessing the USB before I unplug it. Now three of my hard drives can't be seen by Windows, though the others still work. when I hook it up to another computer it works fine. I use the same USB cable to hook up all of my hard drives one at a time. So my USB cable is good. I think that when I unplugged the hard drive this one time, it had a file it still wanted to see and now only this drive does not work only this computer. Then the same thing happens to my other two hard drive after I used it for a week with the same cables. How can I fix this?

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  • How to use non-free drivers during debian install

    - by blokeley
    I'm trying to install debian stable using unetbootin. The install process fails with "network autoconfiguration failed", probably due to the ethernet driver not working. My Lenovo U350 has a Broadcom BCM57780 which does not seem to be supported out-of-the-box: there are various bug reports here, here and here, but I don't know if the fix has made it into debian (6) stable. One discussion says that you have to use an ethernet driver from the firmware-linux-nonfree package. I'm not sure that this is correct because the BCM57780 is not in the list of drivers in firmware-linux-nonfree. The specific question tree is: Is BCM57780 supported in debian stable? If so, what could be wrong? Should I install debian unstable instead? If not, do I need to use firmware-linux-nonfree during installation and, if so, how do I do this? Please note: I've used ubuntu and debian loads in the past but please post line-by-line guidance rather than some cryptic abbreviation of any instructions. Thanks in advance for any help. Updates: Debian stable with non-free drivers did not work. Debian unstable (free drivers only) did not work. Tried loading firmware-iwlwifi_0.28_all.deb from another USB stick to get wireless working rather than BCM57780. The .deb file was found but the network configuration still failed! That's it, I'm giving up. Unfortunately I'll use ubuntu even though the Unity user interface will be very unstable for the next couple of years :(

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  • Eee PC 1015BX ram compatibility?

    - by AdrianaMX
    Asus Eee PC 1015BX Operating System Windows 7 Starter, 32bit CPU AMD Fusion APU C60 1.0GHz (dual core) Processor Graphic AMD Radeon HD 6290 (256 MB Shared) Memory DDR3, 1 x SO-DIMM, 1GB I have upgraded the preloaded "Windows 7 Starter" to "Windows 7 Professional" I want to upgrade the ram, from 1gb (factory) to 4 gb. What should i buy? SODDR3, 4GB, 1066MHZ, PC3-8500, 204PIN? or SODDR3, 4GB, 1333MHZ, PC3-10666, 204PIN? I already know that Windows 7 32-bits can't handle 4gb, only 3gb (but 3gb is better than one stick of 2gb). ASUS send me this link, but i think they are wrong, (or Insufficient Information for me) http://www.kingston.com/us/memory/search/Default.aspx?DeviceType=3&Mfr=ASU&Line=Eee%20PC&Model=71404 Thank you. CPU-Z Chipset Memory Type DDR3 Memory Size 750 MBytes Memory Frequency 532.2 MHz (3:16) CAS# latency (CL) 7.0 RAS# to CAS# delay (tRCD) 7 RAS# Precharge (tRP) 7 Cycle Time (tRAS) 20 Bank Cycle Time (tRC) 27 Memory SPD NO INFO AIDA64 North bridge Properties North bridge AMD K14 IMC Supported Memory Types DDR3-800, DDR3-1066 SDRAM Memory Slots DRAM Slot #1 1 GB (DDR3 SDRAM) Integrated Graphics Controller Graphics Controller Type AMD Radeon HD 6290 (Wrestler) Graphics Controller Status Enabled Graphics Frame Buffer Size 256 MB

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  • netbook screen stays black

    - by sam113101
    I have an acer aspire one netbook. The screen is black but the computer turns on (LED's are on, fan is spinning, etc.) By black I mean absolutely no backlight. I tried to remove the battery and power it on to "discharge" it (I read that on the Internet, not sure if that ever fixes anything), but no luck. I also tried to replace the RAM stick with another one (which I know for sure is working properly), still no luck. I tried to connect an external monitor and switch to it (fn + f5 on this particular model), still no luck, nothing on the external monitor. I read that flashing the BIOS could fix it (http://community.spiceworks.com/how_to/show/22042-acer-aspire-one-black-screen-of-death), I tried to flash it but basically it doesn't do anything when I power it on with the usb thumb drive. No blinking power button. To me it sounds like it might be a dead motherboard, a dead RAM slot (there's only one), or the BIOS thing. I would like to rule out the BIOS possibility, but I need help. The reason I ruled out the dead screen possibility is that it did not switch to the external display when I pressed fn + f5, am I wrong by assuming so? Thank you for your help.

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  • Managing records of bugs and notes

    - by Jim
    Hi. I want to create a knowledgebase for a piece of software. I'd also like to be able to track bugs and common points of failure in that application. Linking knowledgebase articles to bug records would be a real boon, as would the ability to do complex queries for particular articles and bugs on the basis of tags or metadata. I've never done anything like this before, and like to install as little as possible. I've been looking at creating a wiki with Wiki On A Stick, and it seems to offer a lot. But I can't make complex queries. I can create pages that list all 'articles' with a particular single tag, but I can't specify multiple tags or filters. Is there any software that can help? I don't want to spend money until I've tried something out thoroughly, and I'd ideally like something that demands little-to-no installation. Are there any tools that can help me? If something could easily export its data, or stored data in XML, that would be a real plus too. Otherwise, are there any simple apps that allow me to set up forms for bugs, store data as XML then query and process that XML on demand? Thanks in advance.

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  • Toshiba Satellite C665 Rebooting from Standby

    - by Coodu
    I currently am working on a C665 with a strange issue. When the panel is closed the notebook will put itself to sleep in the usual way, and the power LED changes to the pulse to indicate that the device is asleep. However, when the panel is opened to resume using the notebook, the system will restart itself, instead beginning from the Toshiba logo and proceed to boot back in to W7. I should also note that each time this occurs, the "Windows Startup Recovery" option occurs, indicating that the system was not shut down correctly. Some things I have tried: Updated to latest Toshiba BIOS. Returned BIOS settings to their defaults. Swapped Memory to known good module, tested KGM in both memory slots within system. Confirmed that power settings are set to sleep/wake when power button is pressed. Ran a quick HDD fitness test using a parted magic USB stick. Checked for BSOD logs using BlueScreenView, none found. Ran src, no violations found. Any ideas? I have a good feeling the system is restarting itself, but in the event viewer there is a "Kernel Power" error, but it simply says "The system was not shut down correctly." Perhaps a bad driver? I'm not sure. Any advice would be great.

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  • HAProxy appsession vs cookie precedence

    - by user1139473
    I am trying to find the best solution for balancing and keeping persistence on our application behind HAProxy. Here is our basic configuration: https://gist.github.com/endzyme/1804046b23c37beba520 After playing around with taking members down and up and also reloading the haproxy (with -sf) I have noticed that appsession isn't 100% effective, it would appear that sometimes it doesn't always 'request-learn'. I also tried to add a cookie JSESSION prefix to balance in case request-learn didn't take. Unfortunately it would present scenarios where the prefix would list svr2 but it was balanced to a different server. I am assuming it's because the appsession table takes first then sticks on that before using the cookie parameter. I have not tested with using cookie as an inserted option (not prefix on existing cookie) but I am thinking it would yield similar results. My question is: Which one is checked first, appsession or cookie, and is it an immediate catch after it reads the first one, or a fall through? Also as a follow up - is it not recommended to use both in the same backend? Cookie as I understand takes less memory resources, is agnostic to reloads and has way better reliability of persistence. Appsession I assume takes less cpu resource, since it's reading not writing. (Bonus Question: is there a way to inspect appsession/cookie table map? socket show table doesn't show anything except stick-tables) Many thanks in advance, -Nick

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  • Hp Pavilion dv6000 wont boot right and freezes

    - by MalwareManiac
    I have an hp pavilion dv6000 that was having windows issues recently including randomly freezing. I eventually concluded that the hard drive was bad (And I was correct as the bad drive started making funny noises and quit working soon after). So I replaced it with a known good drive and put windows on it and it worked for a few hours. After a few restarts startup didn't even make it to the login screen. It just stays at a lighted black screen until I restarted. After another restart it made it to windows but then froze after a few minutes. A few more restarts yielded one of these two results. Like I mentioned earlier I have a know good drive in it and I also replaced the memory that was in it with a know good stick along with running memtest with no errors. So What does that leave? a corrupted windows installation? Motherboard? CPU? Any ideas?

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  • Safely transfer files from pc with internet connection to lan without allowing any other form of communication

    - by Hugh Quenneville
    In the company that I work there are computers that are connected to the Internet and computers that are connected to a Local Area Network. The LAN is considered a "safe zone" and the files that reside there should never be copied/moved to a computer that has Internet Access. So, now, if we want to download an installer for an application for example, we download it in a pc that has Internet Access and then move it using a "secure USB stick" to the Local Area Network. Is there a way to create an "safe, one-way connection" between a computer with Internet access and a computer from the LAN? This practically means that only files from the computer with the Internet access can be copied/moved to the LAN. In addition to that, if you want to transfer files you would have to provide your security credentials for the network (so, that only users with the appropriate access levels will be able to transfer files). Is it possible to create something like that and make it completely safe (or at least "equally safe" with the USB method that we currently use) or the fact that the computer with Internet access is connected with a wire to the LAN is a security risk by itself? NOTE: the LAN setup involves 2 Windows 2003 servers with Active Directory, Web servers and pretty much all the services that you would expect to find in a Windows network.

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  • Mysql: Working With 192 Trillion Records... (Yes, 192 Trillion)

    - by Sarah
    Here's the question... Considering 192 trillion records, what should my considerations be? My main concern is speed. Here's the table... CREATE TABLE `ref` ( `id` INTEGER(13) AUTO_INCREMENT DEFAULT NOT NULL, `rel_id` INTEGER(13) NOT NULL, `p1` INTEGER(13) NOT NULL, `p2` INTEGER(13) DEFAULT NULL, `p3` INTEGER(13) DEFAULT NULL, `s` INTEGER(13) NOT NULL, `p4` INTEGER(13) DEFAULT NULL, `p5` INTEGER(13) DEFAULT NULL, `p6` INTEGER(13) DEFAULT NULL, PRIMARY KEY (`id`), KEY (`s`), KEY (`rel_id`), KEY (`p3`), KEY (`p4`) ); Here's the queries... SELECT id, s FROM ref WHERE red_id="$rel_id" AND p3="$p3" AND p4="$p4" SELECT rel_id, p1, p2, p3, p4, p5, p6 FROM ref WHERE id="$id" INSERT INTO rel (rel_id, p1, p2, p3, s, p4, p5, p6) VALUES ("$rel_id", "$p1", "$p2", "$p3", "$s", "$p4", "$p5", "$p6") Here's some notes... The SELECT's will be done much more frequently than the INSERT. However, occasionally I want to add a few hundred records at a time. Load-wise, there will be nothing for hours then maybe a few thousand queries all at once. Don't think I can normalize any more (need the p values in a combination) The database as a whole is very relational. This will be the largest table by far (next largest is about 900k) UPDATE (08/11/2010) Interestingly, I've been given a second option... Instead of 192 trillion I could store 2.6*10^16 (15 zeros, meaning 26 Quadrillion)... But in this second option I would only need to store one bigint(18) as the index in a table. That's it - just the one column. So I would just be checking for the existence of a value. Occasionally adding records, never deleting them. So that makes me think there must be a better solution then mysql for simply storing numbers... Given this second option, should I take it or stick with the first... [edit] Just got news of some testing that's been done - 100 million rows with this setup returns the query in 0.0004 seconds [/edit]

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  • Handling TclErrors in Python

    - by anteater7171
    In the following code I'll get the following error if I right click the window that pops up. Then go down to the very bottom entry widget then delete it's contents. It seems to be giving me a TclError. How do I go about handeling such an error? The Error Exception in Tkinter callback Traceback (most recent call last): File "C:\Python26\Lib\lib-tk\Tkinter.py", line 1410, in __call__ return self.func(*args) File "C:\Python26\CPUDEMO.py", line 503, in I TL.sclS.set(S1) File "C:\Python26\Lib\lib-tk\Tkinter.py", line 2765, in set self.tk.call(self._w, 'set', value) TclError: expected floating-point number but got "" The Code #F #PIthon.py # Import/Setup import Tkinter import psutil,time import re from PIL import Image, ImageTk from time import sleep class simpleapp_tk(Tkinter.Tk): def __init__(self,parent): Tkinter.Tk.__init__(self,parent) self.parent = parent self.initialize() def initialize(self): Widgets self.menu = Tkinter.Menu(self, tearoff = 0 ) M = [ "Options...", "Exit"] self.selectedM = Tkinter.StringVar() self.menu.add_radiobutton( label = 'Hide', variable = self.selectedM, command = self.E ) self.menu.add_radiobutton( label = 'Bump', variable = self.selectedM, command = self.E ) self.menu.add_separator() self.menu.add_radiobutton( label = 'Options...', variable = self.selectedM, command = self.E ) self.menu.add_separator() self.menu.add_radiobutton( label = 'Exit', variable = self.selectedM, command = self.E ) self.frame1 = Tkinter.Frame(self,bg='grey15',relief='ridge',borderwidth=4,width=185, height=39) self.frame1.grid() self.frame1.grid_propagate(0) self.frame1.bind( "<Button-3><ButtonRelease-3>", self.D ) self.frame1.bind( "<Button-2><ButtonRelease-2>", self.C ) self.frame1.bind( "<Double-Button-1>", self.C ) self.labelVariable = Tkinter.StringVar() self.label = Tkinter.Label(self.frame1,textvariable=self.labelVariable,fg="lightgreen",bg="grey15",borderwidth=1,font=('arial', 10, 'bold')) self.label.grid(column=1,row=0,columnspan=1,sticky='nsew') self.label.bind( "<Button-3><ButtonRelease-3>", self.D ) self.label.bind( "<Button-2><ButtonRelease-2>", self.C ) self.label.bind( "<Double-Button-1>", self.C ) self.F() self.overrideredirect(1) self.wm_attributes("-topmost", 1) global TL1 TL1 = Tkinter.Toplevel(self) TL1.wm_geometry("+0+5000") TL1.overrideredirect(1) TL1.button = Tkinter.Button(TL1,text="? CPU",fg="lightgreen",bg="grey15",activeforeground="lightgreen", activebackground='grey15',borderwidth=4,font=('Arial', 8, 'bold'),command=self.J) TL1.button.pack(ipadx=1) Events def Reset(self): self.label.configure(font=('arial', 10, 'bold'),fg='Lightgreen',bg='grey15',borderwidth=0) self.labela.configure(font=('arial', 8, 'bold'),fg='Lightgreen',bg='grey15',borderwidth=0) self.frame1.configure(bg='grey15',relief='ridge',borderwidth=4,width=224, height=50) self.label.pack(ipadx=38) def helpmenu(self): t2 = Tkinter.Toplevel(self) Tkinter.Label(t2, text='This is a help menu', anchor="w",justify="left",fg="darkgreen",bg="grey90",relief="ridge",borderwidth=5,font=('Arial', 10)).pack(fill='both', expand=1) t2.resizable(False,False) t2.title('Help') menu = Tkinter.Menu(self) t2.config(menu=menu) filemenu = Tkinter.Menu(menu) menu.add_cascade(label="| Exit |", menu=filemenu) filemenu.add_command(label="Exit", command=t2.destroy) def aboutmenu(self): t1 = Tkinter.Toplevel(self) Tkinter.Label(t1, text=' About:\n\n CPU Usage v1.0\n\n Publisher: Drew French\n Date: 05/09/10\n Email: [email protected] \n\n\n\n\n\n\n Written in Python 2.6.4', anchor="w",justify="left",fg="darkgreen",bg="grey90",relief="sunken",borderwidth=5,font=('Arial', 10)).pack(fill='both', expand=1) t1.resizable(False,False) t1.title('About') menu = Tkinter.Menu(self) t1.config(menu=menu) filemenu = Tkinter.Menu(menu) menu.add_cascade(label="| Exit |", menu=filemenu) filemenu.add_command(label="Exit", command=t1.destroy) def A (self,event): TL.entryVariable1.set(TL.sclY.get()) TL.entryVariable2.set(TL.sclX.get()) Y = TL.sclY.get() X = TL.sclX.get() self.wm_geometry("+" + str(X) + "+" + str(Y)) def B(self,event): Y1 = TL.entryVariable1.get() X1 = TL.entryVariable2.get() self.wm_geometry("+" + str(X1) + "+" + str(Y1)) TL.sclY.set(Y1) TL.sclX.set(X1) def C(self,event): s = self.wm_geometry() geomPatt = re.compile(r"(\d+)?x?(\d+)?([+-])(\d+)([+-])(\d+)") m = geomPatt.search(s) X3 = m.group(4) Y3 = m.group(6) M = int(Y3) - 150 P = M + 150 while Y3 > M: sleep(0.0009) Y3 = int(Y3) - 1 self.update_idletasks() self.wm_geometry("+" + str(X3) + "+" + str(Y3)) sleep(2.00) while Y3 < P: sleep(0.0009) Y3 = int(Y3) + 1 self.update_idletasks() self.wm_geometry("+" + str(X3) + "+" + str(Y3)) def D(self, event=None): self.menu.post( event.x_root, event.y_root ) def E(self): if self.selectedM.get() =='Options...': Setup global TL TL = Tkinter.Toplevel(self) menu = Tkinter.Menu(TL) TL.config(menu=menu) filemenu = Tkinter.Menu(menu) menu.add_cascade(label="| Menu |", menu=filemenu) filemenu.add_command(label="Instruction Manual...", command=self.helpmenu) filemenu.add_command(label="About...", command=self.aboutmenu) filemenu.add_separator() filemenu.add_command(label="Exit Options", command=TL.destroy) filemenu.add_command(label="Exit", command=self.destroy) helpmenu = Tkinter.Menu(menu) menu.add_cascade(label="| Help |", menu=helpmenu) helpmenu.add_command(label="Instruction Manual...", command=self.helpmenu) helpmenu.add_separator() helpmenu.add_command(label="Quick Help...", command=self.helpmenu) Title TL.label5 = Tkinter.Label(TL,text="CPU Usage: Options",anchor="center",fg="black",bg="lightgreen",relief="ridge",borderwidth=5,font=('Arial', 18, 'bold')) TL.label5.pack(padx=15,ipadx=5) X Y scale TL.separator = Tkinter.Frame(TL,height=7, bd=1, relief='ridge', bg='grey95') TL.separator.pack(pady=5,padx=5) # TL.sclX = Tkinter.Scale(TL.separator, from_=0, to=1500, orient='horizontal', resolution=1, command=self.A) TL.sclX.grid(column=1,row=0,ipadx=27, sticky='w') TL.label1 = Tkinter.Label(TL.separator,text="X",anchor="s",fg="black",bg="grey95",font=('Arial', 8 ,'bold')) TL.label1.grid(column=0,row=0, pady=1, sticky='S') TL.sclY = Tkinter.Scale(TL.separator, from_=0, to=1500, resolution=1, command=self.A) TL.sclY.grid(column=2,row=1,rowspan=2,sticky='e', padx=4) TL.label3 = Tkinter.Label(TL.separator,text="Y",fg="black",bg="grey95",font=('Arial', 8 ,'bold')) TL.label3.grid(column=2,row=0, padx=10, sticky='e') TL.entryVariable2 = Tkinter.StringVar() TL.entry2 = Tkinter.Entry(TL.separator,textvariable=TL.entryVariable2, fg="grey15",bg="grey90",relief="sunken",insertbackground="black",borderwidth=5,font=('Arial', 10)) TL.entry2.grid(column=1,row=1,ipadx=20, pady=10,sticky='EW') TL.entry2.bind("<Return>", self.B) TL.label2 = Tkinter.Label(TL.separator,text="X:",fg="black",bg="grey95",font=('Arial', 8 ,'bold')) TL.label2.grid(column=0,row=1, ipadx=4, sticky='W') TL.entryVariable1 = Tkinter.StringVar() TL.entry1 = Tkinter.Entry(TL.separator,textvariable=TL.entryVariable1, fg="grey15",bg="grey90",relief="sunken",insertbackground="black",borderwidth=5,font=('Arial', 10)) TL.entry1.grid(column=1,row=2,sticky='EW') TL.entry1.bind("<Return>", self.B) TL.label4 = Tkinter.Label(TL.separator,text="Y:", anchor="center",fg="black",bg="grey95",font=('Arial', 8 ,'bold')) TL.label4.grid(column=0,row=2, ipadx=4, sticky='W') TL.label7 = Tkinter.Label(TL.separator,text="Text Colour:",fg="black",bg="grey95",font=('Arial', 8 ,'bold')) TL.label7.grid(column=1,row=3,stick="W",ipady=10) TL.selectedP = Tkinter.StringVar() TL.opt1 = Tkinter.OptionMenu(TL.separator, TL.selectedP,'Normal', 'White','Black', 'Blue', 'Steel Blue','Green','Light Green','Yellow','Orange' ,'Red',command=self.G) TL.opt1.config(fg="black",bg="grey90",activebackground="grey90",activeforeground="black", anchor="center",relief="raised",direction='right',font=('Arial', 10)) TL.opt1.grid(column=1,row=4,sticky='EW',padx=20,ipadx=20) TL.selectedP.set('Normal') TL.label7 = Tkinter.Label(TL.separator,text="Refresh Rate:",fg="black",bg="grey95",font=('Arial', 8 ,'bold')) TL.label7.grid(column=1,row=5,stick="W",ipady=10) TL.sclS = Tkinter.Scale(TL.separator, from_=10, to=2000, orient='horizontal', resolution=10, command=self.H) TL.sclS.grid(column=1,row=6,ipadx=27, sticky='w') TL.sclS.set(650) TL.entryVariableS = Tkinter.StringVar() TL.entryS = Tkinter.Entry(TL.separator,textvariable=TL.entryVariableS, fg="grey15",bg="grey90",relief="sunken",insertbackground="black",borderwidth=5,font=('Arial', 10)) TL.entryS.grid(column=1,row=7,ipadx=20, pady=10,sticky='EW') TL.entryS.bind("<Return>", self.I) TL.entryVariableS.set(650) # TL.resizable(False,False) TL.title('Options') geomPatt = re.compile(r"(\d+)?x?(\d+)?([+-])(\d+)([+-])(\d+)") s = self.wm_geometry() m = geomPatt.search(s) X = m.group(4) Y = m.group(6) TL.sclY.set(Y) TL.sclX.set(X) if self.selectedM.get() == 'Exit': self.destroy() if self.selectedM.get() == 'Bump': s = self.wm_geometry() geomPatt = re.compile(r"(\d+)?x?(\d+)?([+-])(\d+)([+-])(\d+)") m = geomPatt.search(s) X3 = m.group(4) Y3 = m.group(6) M = int(Y3) - 150 P = M + 150 while Y3 > M: sleep(0.0009) Y3 = int(Y3) - 1 self.update_idletasks() self.wm_geometry("+" + str(X3) + "+" + str(Y3)) sleep(2.00) while Y3 < P: sleep(0.0009) Y3 = int(Y3) + 1 self.update_idletasks() self.wm_geometry("+" + str(X3) + "+" + str(Y3)) if self.selectedM.get() == 'Hide': s = self.wm_geometry() geomPatt = re.compile(r"(\d+)?x?(\d+)?([+-])(\d+)([+-])(\d+)") m = geomPatt.search(s) X3 = m.group(4) Y3 = m.group(6) M = int(Y3) + 5000 self.update_idletasks() self.wm_geometry("+" + str(X3) + "+" + str(M)) TL1.wm_geometry("+0+190") def F (self): G = round(psutil.cpu_percent(), 1) G1 = str(G) + '%' self.labelVariable.set(G1) try: S2 = TL.entryVariableS.get() except ValueError, e: S2 = 650 except NameError: S2 = 650 self.after(int(S2), self.F) def G (self,event): if TL.selectedP.get() =='Normal': self.label.config( fg = 'lightgreen' ) TL1.button.config( fg = 'lightgreen',activeforeground='lightgreen') if TL.selectedP.get() =='Red': self.label.config( fg = 'red' ) TL1.button.config( fg = 'red',activeforeground='red') if TL.selectedP.get() =='Orange': self.label.config( fg = 'orange') TL1.button.config( fg = 'orange',activeforeground='orange') if TL.selectedP.get() =='Yellow': self.label.config( fg = 'yellow') TL1.button.config( fg = 'yellow',activeforeground='yellow') if TL.selectedP.get() =='Light Green': self.label.config( fg = 'lightgreen' ) TL1.button.config( fg = 'lightgreen',activeforeground='lightgreen') if TL.selectedP.get() =='Normal': self.label.config( fg = 'lightgreen' ) TL1.button.config( fg = 'lightgreen',activeforeground='lightgreen') if TL.selectedP.get() =='Steel Blue': self.label.config( fg = 'steelblue1' ) TL1.button.config( fg = 'steelblue1',activeforeground='steelblue1') if TL.selectedP.get() =='Blue': self.label.config( fg = 'blue') TL1.button.config( fg = 'blue',activeforeground='blue') if TL.selectedP.get() =='Green': self.label.config( fg = 'darkgreen' ) TL1.button.config( fg = 'darkgreen',activeforeground='darkgreen') if TL.selectedP.get() =='White': self.label.config( fg = 'white' ) TL1.button.config( fg = 'white',activeforeground='white') if TL.selectedP.get() =='Black': self.label.config( fg = 'black') TL1.button.config( fg = 'black',activeforeground='black') def H (self,event): TL.entryVariableS.set(TL.sclS.get()) S = TL.sclS.get() def I (self,event): S1 = TL.entryVariableS.get() TL.sclS.set(S1) TL.sclS.set(TL.sclS.get()) S1 = TL.entryVariableS.get() TL.sclS.set(S1) def J (self): s = self.wm_geometry() geomPatt = re.compile(r"(\d+)?x?(\d+)?([+-])(\d+)([+-])(\d+)") m = geomPatt.search(s) X3 = m.group(4) Y3 = m.group(6) M = int(Y3) - 5000 self.update_idletasks() self.wm_geometry("+" + str(X3) + "+" + str(M)) TL1.wm_geometry("+0+5000") Loop if name == "main": app = simpleapp_tk(None) app.mainloop()

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  • Dealing with external processes

    - by Jesse Aldridge
    I've been working on a gui app that needs to manage external processes. Working with external processes leads to a lot of issues that can make a programmer's life difficult. I feel like maintenence on this app is taking an unacceptably long time. I've been trying to list the things that make working with external processes difficult so that I can come up with ways of mitigating the pain. This kind of turned into a rant which I thought I'd post here in order to get some feedback and to provide some guidance to anybody thinking about sailing into these very murky waters. Here's what I've got so far: Output from the child can get mixed up with output from the parent. This can make both outputs misleading and hard to read. It can be hard to tell what came from where. It becomes harder to figure out what's going on when things are asynchronous. Here's a contrived example: import textwrap, os, time from subprocess import Popen test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) proc = Popen('python -B "%s"' % test_path) for i in range(3): print 'Hello %i' % i time.sleep(1) os.remove(test_path) I guess I could have the child process write its output to a file. But it can be annoying to have to open up a file every time I want to see the result of a print statement. If I have code for the child process I could add a label, something like print 'child: Hello %i', but it can be annoying to do that for every print. And it adds some noise to the output. And of course I can't do it if I don't have access to the code. I could manually manage the process output. But then you open up a huge can of worms with threads and polling and stuff like that. A simple solution is to treat processes like synchronous functions, that is, no further code executes until the process completes. In other words, make the process block. But that doesn't work if you're building a gui app. Which brings me to the next problem... Blocking processes cause the gui to become unresponsive. import textwrap, sys, os from subprocess import Popen from PyQt4.QtGui import * from PyQt4.QtCore import * test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) app = QApplication(sys.argv) button = QPushButton('Launch process') def launch_proc(): # Can't move the window until process completes proc = Popen('python -B "%s"' % test_path) proc.communicate() button.connect(button, SIGNAL('clicked()'), launch_proc) button.show() app.exec_() os.remove(test_path) Qt provides a process wrapper of its own called QProcess which can help with this. You can connect functions to signals to capture output relatively easily. This is what I'm currently using. But I'm finding that all these signals behave suspiciously like goto statements and can lead to spaghetti code. I think I want to get sort-of blocking behavior by having the 'finished' signal from QProcess call a function containing all the code that comes after the process call. I think that should work but I'm still a bit fuzzy on the details... Stack traces get interrupted when you go from the child process back to the parent process. If a normal function screws up, you get a nice complete stack trace with filenames and line numbers. If a subprocess screws up, you'll be lucky if you get any output at all. You end up having to do a lot more detective work everytime something goes wrong. Speaking of which, output has a way of disappearing when dealing external processes. Like if you run something via the windows 'cmd' command, the console will pop up, execute the code, and then disappear before you have a chance to see the output. You have to pass the /k flag to make it stick around. Similar issues seem to crop up all the time. I suppose both problems 3 and 4 have the same root cause: no exception handling. Exception handling is meant to be used with functions, it doesn't work with processes. Maybe there's some way to get something like exception handling for processes? I guess that's what stderr is for? But dealing with two different streams can be annoying in itself. Maybe I should look into this more... Processes can hang and stick around in the background without you realizing it. So you end up yelling at your computer cuz it's going so slow until you finally bring up your task manager and see 30 instances of the same process hanging out in the background. Also, hanging background processes can interefere with other instances of the process in various fun ways, such as causing permissions errors by holding a handle to a file or someting like that. It seems like an easy solution to this would be to have the parent process kill the child process on exit if the child process didn't close itself. But if the parent process crashes, cleanup code might not get called and the child can be left hanging. Also, if the parent waits for the child to complete, and the child is in an infinite loop or something, you can end up with two hanging processes. This problem can tie in to problem 2 for extra fun, causing your gui to stop responding entirely and force you to kill everything with the task manager. F***ing quotes Parameters often need to be passed to processes. This is a headache in itself. Especially if you're dealing with file paths. Say... 'C:/My Documents/whatever/'. If you don't have quotes, the string will often be split at the space and interpreted as two arguments. If you need nested quotes you can use ' and ". But if you need to use more than two layers of quotes, you have to do some nasty escaping, for example: "cmd /k 'python \'path 1\' \'path 2\''". A good solution to this problem is passing parameters as a list rather than as a single string. Subprocess allows you to do this. Can't easily return data from a subprocess. You can use stdout of course. But what if you want to throw a print in there for debugging purposes? That's gonna screw up the parent if it's expecting output formatted a certain way. In functions you can print one string and return another and everything works just fine. Obscure command-line flags and a crappy terminal based help system. These are problems I often run into when using os level apps. Like the /k flag I mentioned, for holding a cmd window open, who's idea was that? Unix apps don't tend to be much friendlier in this regard. Hopefully you can use google or StackOverflow to find the answer you need. But if not, you've got a lot of boring reading and frusterating trial and error to do. External factors. This one's kind of fuzzy. But when you leave the relatively sheltered harbor of your own scripts to deal with external processes you find yourself having to deal with the "outside world" to a much greater extent. And that's a scary place. All sorts of things can go wrong. Just to give a random example: the cwd in which a process is run can modify it's behavior. There are probably other issues, but those are the ones I've written down so far. Any other snags you'd like to add? Any suggestions for dealing with these problems?

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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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  • XNA Notes 008

    - by George Clingerman
    This week has been a rough one. I’ve been sick and then in some kind of slump for my afternoon coding sessions. It could be from the cold, could be I’m still tired from writing that Windows Phone 7 game development book (which is out now!) or it could just be I’m tired of winter and want some sunshine. All I know is that even while I’m stick, the XNA world keeps going along at it’s whirlwind pace. Below are the things I caught in between my coughing fits.. Time Critical XNA News: The 2011 MVP summit is almost here so pass along your feelings and thoughts so the MVPs can take them and share them with the team in person http://forums.create.msdn.com/forums/p/76317/464136.aspx#464136 Dream Build Play - there’s no new announcement yet, but you can’t get much more to the end of February than this! http://www.dreambuildplay.com/Main/Home.aspx XNA Team: Dean Johnson from the XNA team shares an excellent way of handling Guide.IsTrialMode on WP7 http://blogs.msdn.com/b/dejohn/archive/2011/02/21/calling-guide-istrialmode-on-windows-phone-7.aspx Nick Gravelyn tries a new tactic in deciding if there’s enough interest to develop a sequel or not. Don’t YOU want Pixel Man 2 to come out? http://nickgravelyn.com/pixelman2/ XNA MVPs: Andy “The ZMan” Dunn finally shares what he’s been secretly working on these past 4 months http://twitter.com/#!/The_Zman/status/40590269392887808 http://www.youtube.com/watch?v=Rg8Z0ZdYbvg&feature=youtu.be Joel Martinez lets developers around NYC know they should by signing up for Game Hack Day http://twitter.com/joelmartinez/statuses/41118590862102528 http://gamehackday.org/71fdk XNA Developers: Michael McLaughlin shares an XNA RenderTarget2D Sample http://geekswithblogs.net/mikebmcl/archive/2011/02/18/xna-rendertarget2d-sample.aspx Martin Caine starts a new series on Deferred Rendering in XNA 4.0 http://twitter.com/#!/MartinCaine/status/39735221339291648 http://martincaine.com/xna/deferred_rendering_in_xna_4_introduction ElemenyCy posts about his fun time with the IntermediateSerializer http://www.ubergamermonkey.com/xna/holy-bloated-xml-batman/ Ben Kane releases a narrated dev diary video for Project Splice. Let him know if you’d like to see more! (I know I do!) http://twitter.com/#!/benkane/status/39846959498002432 http://www.youtube.com/watch?v=1EmziXZUo08&feature=youtu.be Jason Swearingen (of Novaleaf) posts his part 1 of Spatial Partitioning solutions http://altdevblogaday.org/2011/02/21/spatial-partitioning-part-1-survey-of-spatial-partitioning-solutions/ Brian Lawson of Dark Flow Studios shares what his been up to lately with lots of pretty screenshots and hints of announcements from Microsoft... http://www.darkflowstudios.com/entry/short-and-sweet-part-1 Luke Avery starts a new blog where he plans on making XNA tutorials for beginners (and he’s got a few started already!) http://programmingwithovery.wordpress.com/ Xbox LIVE Indie Games (XBLIG): GameMarx Episode 10 http://www.gamemarx.com/video/the-show/24/ep-10-february-18-2010.aspx Minecraft clone FortressCraft coming to XBLIG http://www.eurogamer.net/articles/2011-02-23-minecraft-clone-fortresscraft-hits-xblig ezMuze+ starts an IndieGoGo fundraiser campaign to help fund their second game and get it onto even more devices! http://www.indiegogo.com/ezmuze Gamergeddon XBLIG round up http://www.gamergeddon.com/2011/02/20/xbox-indie-game-round-up-february-20th/?utm_campaign=twitter&utm_medium=twitter&utm_source=twitter JForce Games loses their Ego http://jforcegames.com/blog/index.php?itemid=121&catid=4 XNA Game Development: @BallerIndustry reminds all XNA developers that the Maths are important ;) http://twitter.com/#!/BallerIndustry/status/39317618280243200 http://www.youtube.com/watch?v=MjV3XDFsjP4&feature=player_embedded#at=106 @suhinini stumbles on an older but extremely useful post on XNA Content Pipeline debugging http://twitter.com/#!/suhinini/status/39270189476352000 http://badcorporatelogo.wordpress.com/2010/10/31/xna-content-pipeline-debugging-4-0/ XNA Game Development Workshops at Singapore Universities http://innovativesingapore.com/2011/02/xna-game-development-workshops-at-singapore-universities/ Indiefreaks announces that IGF v0.3 is out with Xbox 360 support, SunBurn 2.0.12 and it’s now Open Source! http://twitter.com/#!/indiefreaks/status/39391953971982336 @liotral announces a new series on properly designing a game http://twitter.com/#!/liortal53/status/39466905081217024 http://liortalblog.wordpress.com/2011/02/20/hello-cosmos/ Indies and XNA at CodeStock 2011 http://www.gamemarx.com/news/2011/02/20/indies-and-xna-at-codestock-2011.aspx Train Frontier Express posts about XNA Content Hotloading http://trainfrontierexpress.blogspot.com/2011/02/xna-content-hotloading-overview.html Slyprid announces a new character editor in Transmute http://twitter.com/#!/slyprid/status/40146992818696192 http://www.youtube.com/watch?v=OKhFAc78LDs&feature=youtu.be The XNA 2D from the ground up tutorial series http://xna-uk.net/blogs/darkgenesis/archive/2011/02/23/recap-the-xna-2d-from-the-ground-up-tutorial-series.aspx Sgt.Conker posts a “Clingerman” (hey that’s me!) to stay relevant http://www.sgtconker.com/2011/02/posting-a-clingerman-to-stay-relevant/

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  • Oracle SQL Developer Data Modeler: What Tables Aren’t In At Least One SubView?

    - by thatjeffsmith
    Organizing your data model makes the information easier to consume. One of the organizational tools provided by Oracle SQL Developer Data Modeler is the ‘SubView.’ In a nutshell, a SubView is a subset of your model. The Challenge: I’ve just created a model which represents my entire ____________ application. We’ll call it ‘residential lending.’ Instead of having all 100+ tables in a single model diagram, I want to break out the tables by module, e.g. appraisals, credit reports, work histories, customers, etc. I’ve spent several hours breaking out the tables to one or more SubViews, but I think i may have missed a few. Is there an easy way to see what tables aren’t in at least ONE subview? The Answer Yes, mostly. The mostly comes about from the way I’m going to accomplish this task. It involves querying the SQL Developer Data Modeler Reporting Schema. So if you don’t have the Reporting Schema setup, you’ll need to do so. Got it? Good, let’s proceed. Before you start querying your Reporting Schema, you might need a data model for the actual reporting schema…meta-meta data! You could reverse engineer the data modeler reporting schema to a new data model, or you could just reference the PDFs in \datamodeler\reports\Reporting Schema diagrams directory. Here’s a hint, it’s THIS one The Query Well, it’s actually going to be at least 2 queries. We need to get a list of distinct designs stored in your repository. For giggles, I’m going to get a listing including each version of the model. So I can query based on design and version, or in this case, timestamp of when it was added to the repository. We’ll get that from the DMRS_DESIGNS table: SELECT DISTINCT design_name, design_ovid, date_published FROM DMRS_designs Then I’m going to feed the design_ovid, down to a subquery for my child report. select name, count(distinct diagram_id) from DMRS_DIAGRAM_ELEMENTS where design_ovid = :dESIGN_OVID and type = 'Table' group by name having count(distinct diagram_id) < 2 order by count(distinct diagram_id) desc Each diagram element has an entry in this table, so I need to filter on type=’Table.’ Each design has AT LEAST one diagram, the master diagram. So any relational table in this table, only having one listing means it’s not in any SubViews. If you have overloaded object names, which is VERY possible, you’ll want to do the report off of ‘OBJECT_ID’, but then you’ll need to correlate that to the NAME, as I doubt you’re so intimate with your designs that you recognize the GUIDs So I’m going to cheat and just stick with names, but I think you get the gist. My Model Of my almost 90 tables, how many of those have I not added to at least one SubView? Now let’s run my report! Voila! My ‘BEER2′ table isn’t in any SubView! It says ’1′ because the main model diagram counts as a view. So if the count came back as ’2′, that would mean the table was in the main model diagram and in 1 SubView diagram. And I know what you’re thinking, what kind of residential lending program would have a table called ‘BEER2?’ Let’s just say, that my business model has some kinks to work out!

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  • IPS Facets and Info files

    - by mkupfer
    One of the unusual things about IPS is its "facet" feature. For example, if you're a developer using the foo library, you don't install a libfoo-dev package to get the header files. Intead, you install the libfoo package, and your facet.devel setting controls whether you get header files. I was reminded of this recently when I tried to look at some documentation for Emacs Org mode. I was surprised when Emacs's Info browser said it couldn't find the top-level Info directory. I poked around in /usr/share but couldn't find any info files. $ ls -l /usr/share/info ls: cannot access /usr/share/info: No such file or directory Was I was missing a package? $ pkg list -a | egrep "info|emacs" editor/gnu-emacs 23.1-0.175.0.0.0.2.537 i-- editor/gnu-emacs/gnu-emacs-gtk 23.1-0.175.0.0.0.2.537 i-- editor/gnu-emacs/gnu-emacs-lisp 23.1-0.175.0.0.0.2.537 --- editor/gnu-emacs/gnu-emacs-no-x11 23.1-0.175.0.0.0.2.537 --- editor/gnu-emacs/gnu-emacs-x11 23.1-0.175.0.0.0.2.537 i-- system/data/terminfo 0.5.11-0.175.0.0.0.2.1 i-- system/data/terminfo/terminfo-core 0.5.11-0.175.0.0.0.2.1 i-- text/texinfo 4.7-0.175.0.0.0.2.537 i-- x11/diagnostic/x11-info-clients 7.6-0.175.0.0.0.0.1215 i-- $ Hmm. I didn't have the gnu-emacs-lisp package. That seemed an unlikely place to stick the Info files, and pkg(1) confirmed that the info files were not there: $ pkg contents -r gnu-emacs-lisp | grep info usr/share/emacs/23.1/lisp/info-look.el.gz usr/share/emacs/23.1/lisp/info-xref.el.gz usr/share/emacs/23.1/lisp/info.el.gz usr/share/emacs/23.1/lisp/informat.el.gz usr/share/emacs/23.1/lisp/org/org-info.el.gz usr/share/emacs/23.1/lisp/org/org-jsinfo.el.gz usr/share/emacs/23.1/lisp/pcvs-info.el.gz usr/share/emacs/23.1/lisp/textmodes/makeinfo.el.gz usr/share/emacs/23.1/lisp/textmodes/texinfo.el.gz $ Well, if I have what look like the right packages but don't have the right files, the next thing to check are the facets. The first check is whether there is a facet associated with the Info files: $ pkg contents -m gnu-emacs | grep usr/share/info dir facet.doc.info=true group=bin mode=0755 owner=root path=usr/share/info file [...] chash=[...] facet.doc.info=true group=bin mode=0444 owner=root path=usr/share/info/mh-e-1 [...] file [...] chash=[...] facet.doc.info=true group=bin mode=0444 owner=root path=usr/share/info/mh-e-2 [...] [...] Yes, they're associated with facet.doc.info. Now let's look at the facet settings on my desktop: $ pkg facet FACETS VALUE facet.locale.en* True facet.locale* False facet.doc.man True facet.doc* False $ Oops. I've got man pages and various English documentation files, but not the Info files. Let's fix that: # pkg change-facet facet.doc.info=True Packages to update: 970 Variants/Facets to change: 1 Create boot environment: No Create backup boot environment: Yes Services to change: 1 DOWNLOAD PKGS FILES XFER (MB) Completed 970/970 181/181 9.2/9.2 PHASE ACTIONS Install Phase 226/226 PHASE ITEMS Image State Update Phase 2/2 PHASE ITEMS Reading Existing Index 8/8 Indexing Packages 970/970 # Now we have the info files: $ ls -F /usr/share/info a2ps.info dir@ flex.info groff-2 regex.info aalib.info dired-x flex.info-1 groff-3 remember ...

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  • Wipe, Delete, and Securely Destroy Your Hard Drive’s Data the Easy Way

    - by The Geek
    Giving a computer to somebody else? Maybe you’re putting it out on Craigslist to sell to a stranger—either way, you’ll want to make sure that your drive is completely wiped, scrubbed, and clean of any personal data. Here’s the easy way to do it. If you only have access to an Ubuntu Live CD or thumb drive, you can actually use that instead if you prefer, and we’ve got you covered with a full guide to securely wiping your PC’s hard drive. Otherwise, keep reading. Wipe the Drive with DBAN Darik’s Boot and Nuke CD is the easiest way to permanently and totally destroy every bit of personal information on that drive—nobody is going to recover a thing once this is done. The first thing you’ll need to do is download a copy of the ISO image, and then burn it to a blank CD with something really useful like Imgburn. Just choose Burn image to Disc at the start screen, select the little file icon, grab the downloaded ISO, and then go. If you need a little more help, we’ve got you covered with a beginner’s guide to burning an ISO image. Once you’re done, stick the disc into the drive, start the PC up, and then once you boot to the DBAN prompt you’ll see a menu. You can pretty much ignore everything on here, and just type… autonuke And there you are, your disk is now being securely wiped. Once it’s all done, you can remove the CD, and then either pack the PC up to sell, or re-install Windows on there if you feel like it. More Advanced Method If you’re really paranoid, want to run a different type of wipe, or just like fiddling with the options, you can choose F3 or hit Enter at the prompt to head to the advanced selection screen. Here you can choose exactly which drive to wipe, or hit the M key to change the method. You’ll be able to choose between a bunch of different wipe options. The Quick Erase is all you really need though.   So there you are, easy PC wiping in one package. What about you? Do you make sure to wipe your old PCs before giving them away? Personally I’ve always just yanked out the hard drives before I got rid of an old PC, but that’s just me. Download DBAN from dban.org Similar Articles Productive Geek Tips Use an Ubuntu Live CD to Securely Wipe Your PC’s Hard DriveHow to Dispose of Old Computers ResponsiblyHow To Delete a VHD in Windows 7Speed up External USB Hard Drives in Windows VistaSpeed Up SATA Hard Drives in Windows Vista TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Follow Finder Finds You Twitter Users To Follow Combine MP3 Files Easily QuicklyCode Provides Cheatsheets & Other Programming Stuff Download Free MP3s from Amazon Awe inspiring, inter-galactic theme (Win 7) Case Study – How to Optimize Popular Wordpress Sites

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