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  • How useful is PXE booting?

    - by J. T.
    Hi All, How fast is booting over PXE?. Is it conceivable to boot a linux installation? Does it take a long time? I have never really looked into it at all, but I was considering setting up a compiler farm and thought this might be interesting to try. Does one have a main computer that the PXE answers to to get its image? Can you have multiple PXE images to pick from? Thanks!

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  • ASP.NET MVC 3 (C#) Software Architecture

    - by ryanzec
    I am starting on a relatively large and ambitious ASP.NET MVC 3 project and just thinking about the best way to organize my code. The project is basically going to be a general management system that will be capable of supporting any type management system whether it be a blogging system, cms, reservation system, wikis, forums, project management system, etc…, each of them being just a separate 'module'. You can read more about it on my blog posted here : http://www.ryanzec.com/index.php/blog/details/8 (forgive me, the style of the site kinda sucks). For those who don't want to read the long blog post the basic idea is that the core system itself is nothing more than a users system with an admin interface to manage the users system. Then you just add on module as you need them and the module I will be creating is a simple blog post to test it out before I move on to the big module which is a project management system. Now I am just trying to think of the best way to structure this so that it is easy for users to add in there own modules but easy for me to update to core system without worrying about the user modifying the core code. I think the ideal way would be to have a number of core projects that user is specifically told not to modify otherwise the system may become unstable and future updates would not work. When the user wants to add in there own modules, they would just add in a new project (or multiple projects). The thing is I am not sure that it is even possible to use multiple projects all with their own controllers, razor view template, css, javascript, etc... in one web application. Ideally each module would have some of it own razor view templates, css, javascript, image files and also need access to some of the core razor view templates, css, javascript, image files which would is in a separate project. It is possible to have 1 web application run off of controllers, razor view templates, css, javascript, image files that are store in multiple projects? Is there a better was to structure this to allow the user to easily add in module with having to modify the core code?

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  • Companies and Ships

    - by TechnicalWriting
    I have worked for small, medium, large, and extra large companies and they have something in common with ships. These metaphors have been used before, I know, but I will have a go at them.The small company is like a speed boat, exciting and fast, and can turn on a dime, literally. Captain and crew share a lot of the work. A speed boat has a short range and needs to refuel a lot. It has difficulty getting through bad weather. (Small companies often live quarter to quarter. By the way, if a larger company is living quarter to quarter, it is taking on water.)The medium company is is like a battleship. It can maneuver, has a longer range, and the crew is focused on its mission. Its main concern are the other battleships trying to blow it out of the water, but it can respond quickly. Bad weather can jostle it, but it can get through most storms.The large company is like an aircraft carrier; a floating city. It is well-provisioned and can carry a specialized load for a very long range. Because of its size and complexity, it has to be well-organized to be effective and most of its functions are specialized (with little to no functional cross-over). There are many divisions and layers between Captain and crew. It is not very maneuverable; it has to set its course well in advance and have a plan of action.The extra large company is like a cruise liner. It also has to be well-organized and changes in direction are often slow. Some of the people are hard at work behind the scenes to run the ship; others can be along for the ride. They sail the same routes over and over again (often happily) with the occasional cosmetic face-lift to the ship and entertainment. It should stay in warm, friendly waters and avoid risky speed through fields of ice bergs.I have enjoyed my career on the various Ships of Technical Writing, but I get the most of my juice from the battleship where I am closer to the campaign and my contributions have the greater impact on success.Mark Metcalfewww.linkedin.com/in/MarkMetcalfe

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  • Enable Ctrl (or Alt) + arrow keys to mimic 'home' and 'end' functionality

    - by YuKagi
    I am a long time Mac user and I'm now using a Ubuntu machine for development, and while I'm more or less used to a lot of the keyboard shortcuts, one thing I can't get used to is using the 'Home' and 'End' keys to move around lines of text. On a Mac you use "Command + right arrow" to go to the end of a line and "Command + left arrow" to go to the beginning. Is there a way to enable this kind of functionality in Linux? I'm not sure if this would be considered remapping, keyboard shortcuts, or what...

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  • proxy software that supports parallel transfer

    - by est
    Hi guys, I need to setup a really fast proxy server in a remote server, here's the scenario: The server prefetches 3KB of data, mostly HTTP resources. The server send to client 3KB of data, instead of traditional HTTP or SOCKS proxy, the server open multithreaded transfer with 3 connections, send 1KB of data per thread to each connection The client receives 1KBx3, and combine them to the original 3KB data, and return as a local HTTP proxy server. The client display the original data in browser via the local HTTP proxy The latency is not important as long as the transfer rate is good. Does any software like this exist? It's better if it's open source or free ones.

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  • Sucking Less Every Year ?

    - by AdityaGameProgrammer
    Sucking Less Every Year A trail of thought that had been on my mind for a while Quoting directly from the post I've often thought that sucking less every year is how humble programmers improve. You should be unhappy with code you wrote a year ago. If you aren't, that means either A) you haven't learned anything in a year, B) your code can't be improved, or C) you never revisit old code. All of these are the kiss of death for software developers. How often does this happen or not happen to you? How long before you see an actual improvement in your coding ? month, year? Do you ever revisit Your old code? How often does your old code plague you? or how often do you have to deal with your technical debt. It is definitely very painful to fix old bugs n dirty code that we may have done to quickly meet a deadline and those quick fixes ,some cases we may have to rewrite most of the application/code. No arguments about that. Some of the developers i had come across argued that they were already at the evolved stage where their coding doesn't need improvement or cant get improved anymore. Does this happen? If so how many years into coding on a particular language does one expect this to happen?

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  • ERP/CRM Systems. Desktop Based ? Web based? [closed]

    - by Parhs
    I have seen 2-3 ERPs in action. I am wondering what is better. Desktop based application or webbased displayed on a browser. My first experience was with a web based ERP when i was 14 years old.. It was web based and terribly slow... For most simple task you had to do lots of clicks... no keyboard support ..... Pages took ages to load. Last year I worked for migrating to a newer computer some old terminal based cobol application. The computer that worked till today and still has no problem was from 1993. The user interface ofcourse was textbased.. The speed that guys placed orders was amazing! just typing the name of the customer , then 5-10 keys to add a product to order.... Comparing to this ERP the page for placing orders Link (click sales orders) seems terribly slow to add a product... No keyboard shortcut works to save what you added and generally I believe you need 4 times more time to place an order compared to the text interface... Having to use both mouse and keyboard for this task is BAD and sadistic... So how can the heck these people ever use a system like that ??? So in the long run desktop application seems the only way... Of course browsers support shortcuts but the way to overide the defaults that browsers uses isn't cross compatible... That is a huge problem. Finnaly, if we MUST/forced use cloud in near future what about keyboard shortcuts?? I feel confused... I have seen converters of desktop applications to browser applications but are SLOW as hell... The question is what about user friendliness? What kind of application would you use?

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  • Need Help Debugging BSOD

    - by nmuntz
    For the last few days I've been getting a BSOD at least once a day. Apparently the crash has been caused by ntkrpamp.exe and searching on google has revealed that the issue seems to be related to bad RAM. I have run memtest and my RAM modules have no errors on them. I'm pretty sure the issue is related to drivers, but I can't figure out which one. I'm not an expert in interpreting the output of windbg so any pointers would be greatly appreciated. Here is my analysis with WinDbg. It was too long to paste it here. One strange thing i noticed is that my Windows XP is in Spanish (SP3) and ntkrpamp.exe copyright info seems to be in portuguese. Not sure if that could be an issue, perhaps i have the wrong ntkrpamp.exe... Thanks a lot in advance

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  • Windows XP - Repairing Corrupt System32\Config\System File

    - by SimonTewsi
    My apologies for this long post. I would like to describe the mess I'm in then ask some questions about how to fix it: Starting up my Windows XP SP1 machine I got the following message: Windows could not start because the following file is missing or corrupt: \WINDOWS\SYSTEM32\CONFIG\SYSTEM Tried restarting several times with same results then Googled the problem. Tried the fix described here: http://icrontic.com/articles/repair%5Fwindows%5Fxp (since my CPU does not have XD buffer overflow protection I did not set /NOEXECUTE=OPTIN as OS Load Option). This did not work. I then found another fix for the problem on hardwareanalysis.com: Basically, boot to dos prompt (or recovery console if available) and make backups of the following files:- c:\windows\system32\config\system (to c:\windows\tmp\system.bak) c:\windows\system32\config\software (to c:\windows\tmp\software.bak) c:\windows\system32\config\sam (to c:\windows\tmp\sam.bak) c:\windows\system32\config\security (to c:\windows\tmp\security.bak) c:\windows\system32\config\default (to c:\windows\tmp\default.bak) then delete the above files (not the backups!) then copy the above files in c:\windows\repair to the c:\windows\system32\config directory restart your computer This did work (and I wish I'd done it first, since it was completely reversible, unlike the first method). However, afterwards I found that all the user accounts on the PC were gone. I resurrected them by copying the backed up security file back into the system32\config folder (I may have copied the SAM file from backup as well, I cannot remember clearly now). Now the PC boots up and I can log in. However things are still not right. I tried to alter one of the user accounts and found I could not access the User Accounts in the Control Panel. Microsoft KB 919292 had a fix for the problem. However, the fix failed with a Windows Installer error: The Windows Installer Service could not be accessed. This can occur if you are running Windows in safe mode, or if Windows Installer is not correctly installed. Contact your support personnel for assistance. Windows Installer 3.1 was already installed. I reinstalled it but continued to get the Windows Installer error whenever I tried to run the fix in KB 919292. I have since noticed another three problems: 1) Several applications on the PC no longer run, eg Microsoft Word. Shortcuts no longer seem to do anything and if I run the executables directly (eg for Word by running C:\Program Files\Microsoft Office\Office10\Winword.exe) I get a message similar to: "Microsoft Word has not been installed for the current user. Please run setup to install the application." even though the executable is clearly visible in Windows Explorer (and even though Word actually opens - the error dialog appears after Word has opened. Clicking OK to the error dialog closes Word). 2) One or the other of the two fixes I tried for the original problem caused new user profiles to be created. eg My old user profile under the Documents and Settings folder was Simon. The old one still exists but there is now a new one called Simon.DBQ2515. Obviously the new one is being used because Opera (my browser that still works) no longer sees the bookmarks file under my old profile. 3) Probably as a result of fooling around with the Security file, when I try to boot off the Windows XP CD and run the Recovery Console I am now asked for the administrator password. The only problem is there is no administrator account on the PC. There is one account, LocalAdmin, that has administrative rights but when I entered the password for that account it did not work. It is so long since I originally set up the PC that I cannot remember if the original administrator account ever had a password and, if so, what it was. So, my question is: How can I fix this mess? In particular: 1) Having tried the two fixes linked to above, have I irrepairably damaged the Windows instance, requiring a clean reinstallation of Windows + all applications, or should it be possible to get the machine working correctly again without such drastic measures? 2) Is there any way to get around the administrator password so I can use the Recovery Console again, given that there is no account called "administrator" and the password for the one account with admin privileges does not work (and that, before I started the second fix, I was not asked for an administrator password)? 3) Is there any easy way to fix the problem with the applications that think they are not installed? 4) Is there any easy way to fix the problem of the Windows Installer that does not work, even if reinstalled? Cheers Simon

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  • How to fix this navigation issue in my site?

    - by David
    First off I use webs.com for the creation of my site. I have a very basic layout. List of links of the left and content on the right with a heading up top. Now in my list of links every link is an article that I wrote, I have about 25 links going down the left hand side of my site. Problem is when I try out new themes that support horizontal navigation as opposed to vertical navigation I get either a messy overflow of links Or a link called "more" which lists the rest of the articles in a drop down-list across my site. What I wish I had was a simple horizontal navigation like" "home, about, articles" and when the user clicks on articles it would then bring them to a page containing all my articles there. I would prefer it to be in a table like display. That way is not a long list. Anyways any ideas on how I can fix this issue im having? Please let me know if you need more information.

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  • Best multi-platform mobile development tool, or use iPhone tools?

    - by Jesse Millikan
    I may be building a mobile app for a client soon. Their primary focus is the iPhone, but my boss would like to be able to target multiple platforms if it's feasible. The app will probably be a large but technically simple business application backed by a web service. So, here's the question as I see it: What is currently the strongest cross-platform mobile development tool that supports iOS? Would you choose it over native development tools? If you choose native, contrast it with a cross-platform tool you've used. In addition, For a project of the type we're expecting, what's the level of effort for your chosen tool versus other tools? What's the actual level of support of the tool for other platforms and their unique look and feel, capabilities, etc.? How thorough is the documentation of the product? How well do you like the development experience itself, e.g. the language, tools, documentation? Is it something you would choose to do long-term? I'll put a bounty out unless I get fantastic answers.

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  • Sample domain model for online store

    - by Carel
    We are a group of 4 software development students currently studying at the Cape Peninsula University of Technology. Currently, we are tasked with developing a web application that functions as a online store. We decided to do the back-end in Java while making use of Google Guice for persistence(which is mostly irrelevant for my question). The general idea so far to use PHP to create the website. We decided that we would like to try, after handing in the project, and register a business to actually implement the website. The problem we have been experiencing is with the domain model. These are mostly small issues, however they are starting to impact the schedule of our project. Since we are all young IT students, we have virtually no experience in the business world. As such, we spend quite a significant amount of time planning the domain model in the first place. Now, some of the issues we're picking up is say the reference between the Customer entity and the order entity. Currently, we don't have the customer id in the order entity and we have a list of order entities in the customer entity. Lately, I have wondered if the persistence mechanism will put the client id physically in the order table, even if it's not in the entity? So, I started wondering, if you load a customer object, it will search the entire order table for orders with the customer's id. Now, say you have 10 000 customers and 500 000 orders, won't this take an extremely long time? There are also some business processes that I'm not completely clear on. Finally, my question is: does anyone know of a sample domain model out there that is similar to what we're trying to achieve that will be safe to look at as a reference? I don't want to be accused of stealing anybody's intellectual property, especially since we might implement this as a business.

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  • HD read error while booting linux

    - by sidharth sharma
    I have been dual booting windows 7 and ubuntu on my laptop since the past 3 years and all was working fine until I started getting logs like ata1.00: status: { DRDY ERR } ata1.00: error: { UNC } ata1.00: configured for UDMA/133 sd 0:0:0:0: [sda] Unhandled sense code sd 0:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE sd 0:0:0:0: [sda] Sense key: Medium Error [Current][discreptor] I figured it was a hardware problem and ignored it as long as I could until the HD crashed on me. Then I got a brand new HD and put on windows and ubuntu afresh on it but the problem still persists. Any Help?

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  • Why is my query soooooo slow?

    - by geekrutherford
    A stored procedure used in our production environment recently became so slow it cause the calling web service to begin timing out. When running the stored procedure in Query Analyzer it took nearly 3 minutes to complete.   The stored procedure itself does little more than create a small bit of dynamic SQL which calls a view with a where clause at the end.   At first the thought was that the query used within the view needed to be optimized. The query is quite long and therefore easy to jump to this conclusion.   Fortunately, after bringing the issue to the attention of a coworker they asked "is there a where clause, and if so, is there an index on the column(s) in it?" I had no idea and quickly said as much. A quick check on the table/column utilized in the where clause indicated indeed there was no index.   Before adding the index, and after admitting I am no SQL wiz, I checked the internet for info on the difference between clustered and non-clustered indexes. I found the following site quite helpful OdeToCode. After adding the non-clustered index on the column, the query that used to take nearly 3 minutes now takes 10 seconds! Ah, if only I'd thought to do this ahead of time!

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  • Setting up a shared media drive

    - by Sam Brightman
    I want to have a shared media drive be transparently usable to all users, whilst also sticking to FHS and Ubuntu standards. The former takes priority if necessary. I currently mount it at /media/Stuff but /media is supposed to be for external media, I believe. The main issue is setting permissions so that access to read and write to the drive can be granted to multiple users working within the same directories. InstallingANewHardDrive seems both slightly confused and not what I want. It claims that this sets ownership for the top-level directory (despite the recursion flag): sudo chown -R USERNAME:USERNAME /media/mynewdrive And that this will let multiple users create files and sub-directories but only delete their own: sudo chgrp plugdev /media/mynewdrive sudo chmod g+w /media/mynewdrive sudo chmod +t /media/mynewdrive However, the group writeable bit does not seem to get inherited, which is troublesome for keeping things organised (prevents creation inside sub-folders originally made by another user). The sticky bit is probably also unwanted for the same reason, although currently it seems that one userA (perhaps the owner of the mount-point?) can delete the userB's files, but not vice-versa. This is fine, as long as userB can create files inside the directory of userA. So: What is the correct mount point? Is plugdev the correct group? Most importantly, how to set up permissions to maintain an organised media drive? I do not want to be running cron jobs to set permissions regularly!

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  • Can my ISP find out if my wireless is protected or not?

    - by Zakukashi
    Im just wondering how much my ISP knows about my activities. I have a Modem from them this modem then connects to a SITCOM wireless router which then leads to MY PC's, Phones, Laptops. I really need to know if my ISP knows if my router is in unprotected state of wireless or not. The Sitcom box it not theirs, we payed for it long after getting this internet. Does my Sitcom wireless router send data to my ISP on its own, indicating delicate information such as wireless protection on or off? Or does the ISP's modem fish out this information on its own since our wireless router is connected to it? Would greatly appreciate any answer.

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  • Ideas to tackle unwanted bad press/review on Google's SERP?

    - by Rob
    After Googling our company name to our horror we've found someone on Yelp.co.uk has reviewed our company. On the SERP your eye is immediately drawn to the 2 star review some complete stranger has written, which to be honest is pure slander! The most infuriating thing is the person who reviewed our company has never even been a client/customer. It's a bit like me reviewing a restaurant having never eaten or even been in there! We've sent her a private message on Yelp to remove the review and also sent a complaint to Yelp themselves but have yet to get a reply. We've resisted going mad at the reviewer and also requested that she re-review us having just relaunched our new website (it still riles us that she's not even a client though!). We've had genuine customers/clients review us on Yelp yet this 2 star review remains on Google's SERP. Roughly how long would it take to for our new reviews to over take this review? Does anyone have any suggestions as to how we can push the review off the 1st page of Google's SERP or any creative ways in which we can tackle this issue?

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  • Advice on choosing a book to read

    - by Kioshiki
    I would like to ask for some recommendations on useful books to read. Initially I had intended on posting quite a long description of my current issue and asking for advice. But I realised that I didn’t have a clear idea of what I wanted to ask. One thing that is clear to me is that my knowledge in various areas needs improving and reading is one method of doing that. Though choosing the right book to read seems like a task in itself when there are so many books out there. I am a programmer but I also deal with analysis, design & testing. So I am not sure what type of book to read. One option might be to work through two books at the same time. I had thought maybe one about design or practices and another of a more technical focus. Recently I came across one book that I thought might be useful to read: http://xunitpatterns.com/index.html It seems like an interesting book, but the comments I read on amazon.co.uk show that the book is probably longer than it needs to be. Has anyone read it and can comment on this? Another book that I already own and would probably be a good one to finish reading is this: http://www.amazon.co.uk/Code-Complete-Practical-Handbook-Construction/dp/0735619670/ref=sr_1_1?ie=UTF8&qid=1309438553&sr=8-1 Has anyone else read this who can comment on its usefulness? Beyond these two I currently have no clear idea of what to read. I have thought about reading a book related to OO design or the GOF design patterns. But I wonder if I am worrying too much about the process and practices and not focusing on the actual work. I would be very grateful for any suggestions or comments. Many Thanks, Kioshiki

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  • SMTP server to deliver mail to Rails app, how?

    - by Gunchars
    all, this is my first question and I hope I chose the right place to post it. Here's what I need help with: I've been looking for this all day and I'm having a hard time finding a SMTP mail server that would fit the following criteria: lightweight, does one thing and does it good is able to route and deliver local mail to a Rails application The second point could be accomplished in any number of ways. I'm running a VPS, so I have full freedom in how to implement this. It could, for example, put messages straight in the db, pipe them to a helper program that would then process them accordingly or also save messages in a mbox file and run a script after every received message. I'm building a small site so the traffic is not going to be a problem. If there are alternative ways to deliver messages to a Rails app, I'd gladly hear about them. Thank you. EDIT: After long searching, I think I've found what I was looking for. Exim is a mail server that can deliver local mail to pipes. Also, Rails 3 and ActionMailer can make it really easy to process the incoming mail. More info here: http://www.exim.org/exim-html-current/doc/html/spec_html/ch29.html http://guides.rubyonrails.org/action_mailer_basics.html#receiving-emails

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  • Designs for outputting to a spreadsheet

    - by Austin Moore
    I'm working on a project where we are tasked to gather and output various data to a spreadsheet. We are having tons of problems with the file that holds the code to write the spreadsheet. The cell that the data belongs to is hardcoded, so anytime you need to add anything to the middle of the spreadsheet, you have to increment the location for all the fields after that in the code. There are random blank rows, to add padding between sections, and subsections within the sections, so there's no real pattern that we can replicate. Essentially, anytime we have to add or change anything to the spreadsheet it requires a many long and tedious hours. The code is all in this one large file, hacked together overtime in Perl. I've come up with a few OO solutions, but I'm not too familiar with OO programming in Perl and all my attempts at it haven't been great, so I've shied away from it so far. I've suggested we handle this section of the program with a more OO friendly language, but we can't apparently. I've also suggested that we scrap the entire spreadsheet idea, and just move to a webpage, but we can't do that either. We've been working on this project for a few months, and every time we have to change that file, we all dread it. I'm thinking it's time to start some refactoring. However, I don't even know what could make this file easier to work with. The way the output is formatted makes it so that it has to be somewhat hardcoded. I'm wondering if anyone has insight on any design patterns or techniques they have used to tackle a similar problem. I'm open to any ideas. Perl specific answers are welcome, but I am also interested in language-agnostic solutions.

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  • Firefox, Thunderbird, Safari - hangs up on start

    - by takeshin
    I have a strange problem on Windows Vista (Automatic updates). Long time ago I had installed Firefox, Thunderbird, Safari and Opera and they all worked well. Once upon a time, after Windows restart, Firefox, Thunderbird and Safari won't start. [Opera (USB) works fine]. When I start the browser, program name is listed on the processes list, but it is not activated, doesn't show any window. I tried crating new profiles with -ProfileManager, restarting Windows, reinstalling the browsers. I scanned the system for suspected programs and it looks clean. There is 45GB of free HDD space. WTF?

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  • Switching mdadm to an external bitmap

    - by Oli
    I've just read this in another post about improving RAID5/6 write speeds: After increasing stripe cache & switching to external bitmap, my speeds are 160 Mb/s writes, 260 Mb/s reads. :-D I've already found out how to increase the stripe cache and this worked pretty well but I'd like to know more about an external bitmap. I have an incredibly fast (540MB/s) RAID0 SSD that would do well if a bitmap does what I think it does but I'm still very unsure. I've only known about them as long as I've known this post. A few questions: What is a bitmap (in terms of mdadm)? What are the advantages of an internal bitmap (over external)? What are the advantages of an external bitmap (over internal)? How do I switch between the two? I should add that while this is a I'm-bored-let's-break-something thread, I do value the data stored on the RAID array. If doing this is going to put data at significant risk, please let me know.

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  • Script to restart BlackBerry services

    - by ICTdesk.net
    Can somebody give me a script advice/example of how to restart services? I have to restart 17 services, but the first 4 services have to be in the right order and after the restart command is given to one of the services, the next one should be started when the previous one is finished. I know I can restart a service by net command, and I can build a delay by for example a ping command that repeats for an x amount of times, but I never know in advance how long it is going to take for a service to restart. Thanks, Kindest regards, Marcel

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  • Is it faster to create indexes before or after data loading in MySQL?

    - by Josh Glover
    I have a data replication process that drops and recreates a few tables in a target database, then loads them up with data from a source database (running on another host, but that is immaterial to the question at hand). The target database does need primary keys and a few other indexes on its tables, but not during the data loading. I'm currently loading all of the data, then creating the indexes. However, index creation takes a pretty long time--30 minutes of my data loader's 5 and a half hour running time. My intuition tells me that creating the indexes at the end should be faster than creating them first, since the index would need to be rewritten with each insert. Can anyone tell me for sure which way is faster? FWIW, I'm running MySQL 5.1 with InnoDB tables.

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  • Is there a canonical source supporting "all-surrogates"?

    - by user61852
    Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

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