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  • Uninstalling Ubuntu dual-boot bootrec issues

    - by Raymond Standen
    So on my laptop I am currently planning on uninstalling Ubuntu 12.04 so I can upgrade my Windows 7 partition to Windows 8, then install Ubuntu 12.10. My issue being that when I boot the Windows 7 recovery disk, I believe i Need to use cmd to run bootrec /fixboot and bootrec /fixmbr. Now, whilst fixmbr works, fixboot yields me with an error regarding an unrecognised volume. When I turn on my PC now, I am no longer met the GRUB option, so I boot straight into Windows. My question is: As such, do I still need to have fixboot run or can I just format and resize the partitions now even with the error when running fixboot?

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  • My ASUS U32U with fresh Xubuntu install shows a black screen 50-80% of the startups

    - by Jona Ekenberg
    I have recently installed Ubuntu 12.10 with Xubuntu-package on my ASUS U32U notebook (Radeon HD 6320 GPU). The issue I have is that more often than not, after the GRUB-select screen I get a black screen, and three times total white lines (kind of) flashes very quickly (with maybe 5 seconds between each flash). I'm not even able to get to the login-screen (nor the Xubuntu loading screen). At first I thought it was simply me having installed something dumb or messed up some settings, but even after reformatting the partition and installing ubuntu again, the problem remains. Before I formatted it xfce4's window manager wouldn't start either, but it does now (when I am able to see anything). I can access the virual consoles (ctrl+alt+f1), but I can't see anything, but I've managed to shutdown the computer by using it (sudo shutdown -h now).

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  • Migrating Virtual Iron guest to Oracle VM 3.x

    - by scoter
    As stated on the official site, Oracle in 2009, acquired a provider of server virtualization management software named Virtual Iron; you can find all the acquisition details at this link. Into the FAQ on the official site you can also view that, for the future, Oracle plans to fully integrate Virtual Iron technology into Oracle VM products, and any enhancements will be delivered as a part of the combined solution; this is what is going on with Oracle VM 3.x. So, customers started asking us to migrate Virtual Iron guests to Oracle VM. IMPORTANT: This procedure needs a dedicated OVM-Server with no-guests running on top; be careful while execute this procedure on production environments. In these little steps you will find how-to migrate, as fast as possible, your guests between VI ( Virtual Iron ) and Oracle VM; keep in mind that OracleVM has a built-in P2V utility ( Official Documentation )  that you can use to migrate guests between VI and Oracle VM. Concepts: VI repositories.  On VI we have the same "repository" concept as in Oracle VM; the difference between these two products is that VI use a raw-lun as repository ( instead of using ocfs2 and its capabilities, like ref-links ). The VI "raw-lun" repository, with a pure operating-system perspective, may be presented as in this picture: Infact on this "raw-lun" VI create an LVM2 volume-group. The VI "raw-lun" repository, with an hypervisor perspective, may be presented as in this picture: So, the relationships are: LVM2-Volume-Group <-> VI Repository LVM2-Logical-Volume <-> VI guest virtual-disk The first step is to present the VI repository ( raw-lun ) to your dedicated OVM-Server. Prepare dedicated OVM-Server On the OVM-Server ( OVS ) you need to discover new lun and, after that, discover volume-group and logical-volumes containted in VI repository; due to default OVS configuration you need to edit lvm2 configuration file: /etc/lvm/lvm.conf     # By default for OVS we restrict every block device:     # filter = [ "r/.*/" ] and comment the line starting with "filter" as above. Now you have to discover the raw-lun presented and, next, activate volume-group and logical-volumes: #!/bin/bash for HOST in `ls /sys/class/scsi_host`;do echo '- - -' > /sys/class/scsi_host/$HOST/scan; done CPATH=`pwd` cd /dev for DEVICE in `ls sd[a-z] sd?[a-z]`;do echo '1' > /sys/block/$DEVICE/device/rescan; done cd $CPATH cd /dev/mapper for PARTITION in `ls *[a-z] *?[a-z]`;do partprobe /dev/mapper/$PARTITION; done cd $CPATH vgchange -a yAfter that you will see a new device:[root@ovs01 ~]# cd /dev/6000F4B00000000000210135bef64994[root@ovs01 6000F4B00000000000210135bef64994]# ls -l 6000F4B0000000000061013* lrwxrwxrwx 1 root root 77 Oct 29 10:50 6000F4B00000000000610135c3a0b8cb -> /dev/mapper/6000F4B00000000000210135bef64994-6000F4B00000000000610135c3a0b8cb By your OVM-Manager create a guest server with the same definition as on VI:same core number as VI source guestsame memory as VI source guestsame number of disks as VI source guest ( you can create OVS virtual disk with a small size of 1GB because the "clone" will, eventually, extend the size of your new virtual disks )Summarizing:source-virtual-disk path ( VI ):/dev/mapper/6000F4B00000000000210135bef64994-6000F4B00000000000610135c3a0b8cbdest-virtual-disk path ( OVS ):/OVS/Repositories/0004fb00000300006cfeb81c12f12f00/VirtualDisks/0004fb000012000055e0fc4c5c8a35ee.img ** ** = to identify your virtual disk you have verify its name under the "vm.cfg" file of your new guest.Clone VI virtual-disk to OVS virtual-diskdd if=/dev/mapper/6000F4B00000000000210135bef64994-6000F4B00000000000610135c3a0b8cb of=/OVS/Repositories/0004fb00000300006cfeb81c12f12f00/VirtualDisks/0004fb000012000055e0fc4c5c8a35ee.img Clean unsupported parameters and changes on OVS.1. Restore original /etc/lvm/lvm.conf    # By default for OVS we restrict every block device:     filter = [ "r/.*/" ]    and uncomment the line starting with "filter" as above.2. Force-stop lvm2-monitor service  # service lvm2-monitor force-stop 3. Restore original /etc/lvm directories ( archive, backup and cache )  # cd /etc/lvm  # rm -fr archive backup cache; mkdir archive backup cache4. Reboot OVSRefresh OVS repository and start your guest.By OracleVM Manager refresh your repository:By OracleVM Manager start your "migrated" guest: Comments and corrections are welcome.  Simon COTER 

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  • CMS for coding blog

    - by OrgnlDave
    I've got a server with a LAMP stack and such. I'd like to host a blog-type site (or if there's a free place good for this, that would be cool!) that covers a variety of tutorials, interesting content, etc. There are tons of CMS's out there but if you search for tips on ones that do programming type things well, you get tons of hits about web development. I'd like to know if anyone here has recommendations from actually using a CMS for this type of thing or, short of that, can recommend one - not based on generalities like "Joomla! is great!" I'm looking for the least setup time possible. I'm proficient with CSS and I can design a color scheme, so that's not a big problem. As you can expect, attaching files, pictures, and syntax highlighting are musts (C/C++ ish is good). Ability to group posts, perhaps use tags, etc. would be cool too, but not necessary. As I'm writing this, it almost sounds like it'd be easier to custom-code a small PHP site myself.

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  • GRUB fatal installation of Ubuntu 11.10 - Dual boot for Win7

    - by zero
    I have win7 installed in my system and I decided to give Ubuntu a try. I formatted my drive as follow : C:\ - For Win7 - 55G D:\ - Data - 40G E:\ - Unallocated space - 55G - This is where the installation of Ubuntu I tried to install with this partition table (All set as logical) /dev/sda6 /boot - 258 mb /dev/sda7 swap - 2000mb /dev/sda8 / /dev/sda9 /home I get this error in the middle of the installation Unable to install GRUB in /dev/sda6 Executing 'grub-install/dev/sda6' failed This is fatal error I followed this article http://www.linuxbsdos.com/2011/05/22/how-to-dual-boot-windows-7-and-ubuntu-11-04/ but it seems not working for Ubuntu 11.10. Am I missing something in the installation? Any feedback will be helpful.

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  • Customer retention - why most companies have it wrong

    - by Michel Adar
    At least in the US market it is quite common for service companies to offer an initially discounted price to new customers. While this may attract new customers and robe customers from competitors, it is my argument that it is a bad strategy for the company. This strategy gives an incentive to change companies and a disincentive to stay with the company. From the point of view of the customer, after 6 months of being a customer the company rewards the loyalty by raising the price. A better strategy would be to reward customers for staying with the company. For example, by lowering the cost by 5% every year (compound discount so it does never get to zero). This is a very rational thing to do for the company. Acquiring new customers and setting up their service is expensive, new customers also tend to use more of the common resources like customer service channels. It is probably true for most companies that the cost of providing service to a customer of 10 years is lower than providing the same service in the first year of a customer's tenure. It is only logical to pass these savings to the customer. From the customer point of view, the competition would have to offer something very attractive, whether in terms of price or service, in order for the customer to switch. Such a policy would give an advantage to the first mover, but would probably force the competitors to follow suit. Overall, I would expect that this would reduce the mobility in the market, increase loyalty, increase the investment of companies in loyal customers and ultimately, increase competition for providing a better service. Competitors may even try to break the scheme by offering customers the porting of their tenure, but that would not work that well because it would disenchant existing customers and would be costly, assuming that it is costlier to serve a customer through installation and first year. What do you think? Is this better than using "save offers" to retain flip-floppers?

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  • Simple solution now to a problem from 8 years ago. Use SQL windowing function

    - by Kevin Shyr
    Originally posted on: http://geekswithblogs.net/LifeLongTechie/archive/2014/06/10/simple-solution-now-to-a-problem-from-8-years-ago.aspxI remember having this problem 8 years ago. We had to find the top 5 donor per month and send out some awards. The SQL we came up with was clunky and had lots of limitation (can only do one year at a time), then switch the where clause and go again. Fast forward 8 years, I got a similar problem where we had to find the top 3 combination of 2 fields for every single day. And the solution is this elegant: SELECT CAST(eff_dt AS DATE) AS "RecordDate" , status_cd , nbr , COUNT(*) AS occurance , ROW_NUMBER() OVER (PARTITION BY CAST(eff_dt AS DATE) ORDER BY COUNT(*) DESC) RowNum FROM table1 WHERE RowNum < 4 GROUP BY CAST(eff_dt AS DATE) , status_cd , nbr If only I had this 8 years ago. :) Life is good now!

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  • Is there an excuse for excessively short variable names?

    - by KChaloux
    This has become a large frustration with the codebase I'm currently working in; many of our variable names are short and undescriptive. I'm the only developer left on the project, and there isn't documentation as to what most of them do, so I have to spend extra time tracking down what they represent. For example, I was reading over some code that updates the definition of an optical surface. The variables set at the start were as follows: double dR, dCV, dK, dDin, dDout, dRin, dRout dR = Convert.ToDouble(_tblAsphere.Rows[0].ItemArray.GetValue(1)); dCV = convert.ToDouble(_tblAsphere.Rows[1].ItemArray.GetValue(1)); ... and so on Maybe it's just me, but it told me essentially nothing about what they represented, which made understanding the code further down difficult. All I knew was that it was a variable parsed out specific row from a specific table, somewhere. After some searching, I found out what they meant: dR = radius dCV = curvature dK = conic constant dDin = inner aperture dDout = outer aperture dRin = inner radius dRout = outer radius I renamed them to essentially what I have up there. It lengthens some lines, but I feel like that's a fair trade off. This kind of naming scheme is used throughout a lot of the code however. I'm not sure if it's an artifact from developers who learned by working with older systems, or if there's a deeper reason behind it. Is there a good reason to name variables this way, or am I justified in updating them to more descriptive names as I come across them?

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  • Architecture of an action multiplayer game from scratch

    - by lcf
    Not sure whether it's a good place to ask (do point me to a better one if it's not), but since what we're developing is a game - here it goes. So this is a "real-time" action multiplayer game. I have familiarized myself with concepts like lag compensation, view interpolation, input prediction and pretty much everything that I need for this. I have also prepared a set of prototypes to confirm that I understood everything correctly. My question is about the situation when game engine must be rewind to the past to find out whether there was a "hit" (sometimes it may involve the whole 'recomputation' of the world from that moment in the past up to the present moment. I already have a piece of code that does it, but it's not as neat as I need it to be. The domain logic of the app (the physics of the game) must be separated from the presentation (render) and infrastructure tools (e.g. the remote server interaction specifics). How do I organize all this? :) Is there any worthy implementation with open sources I can take a look at? What I'm thinking is something like this: -> Render / User Input -> Game Engine (this is the so called service layer) -> Processing User Commands & Remote Server -> Domain (Physics) How would you add into this scheme the concept of "ticks" or "interactions" with the possibility to rewind and recalculate "the game"? Remember, I cannot change the Domain/Physics but only the Game Engine. Should I store an array of "World's States"? Should they be just some representations of the world, optimized for this purpose somehow (how?) or should they be actual instances of the world (i.e. including behavior and all that). Has anybody had similar experience? (never worked on a game before if that matters)

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  • Compiz runs almost at 100% and the system is slow, what can I do?

    - by Heiner Valverde
    My system became very slow out of the sudden, yesterday Compiz was running extremely smooth, today it started working very slow and slowing the computer. What I've done so far was to resize my swap partition to 6 gigabytes (my computer has 3 gigabytes of RAM), before it was on 5.1 gigabytes, so I though that was the reason of this but still not. Also I tested running only metacity by running metacity --replace and also with Mutter. With metacity works really great no problem but, in the other hand, with mutter the computer works slower than running compiz instead. I am using the Nvidia driver version 173.14.28 and my X Server version as reports the NVidia X Server Settings is the 11.0. My Linux kernel running on this computer is 2.6.35-25-generic and my ubuntu version is 10.10. Any help will be appreciated.

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  • Ubuntu install and boot failure 11.10

    - by Robert Moody
    I installed Ubuntu 11.10 on my machine alongside Vista, and upgraded to 12.4. I decided I liked 11.10 better, so I tried to install that again as my only OS, except I increased the size of the swap file partition to 2 gigs. It boots up fine off the CD, but when I install, it gives me a non-specific error, and returns me to the desktop. When attempting to boot off the hard drive, I get a black screen with a blinking underscore that starts in the corner, drops a couple spaces, and stays there. I managed to install 9.04, and am currently using that. The computer is a little outdated, but was fired up for the very first time last week, so the hard drive is in new condition and the CD rom drive is fine too. Running a 3GHzX2 processor. I ran a memory test, which came back fine, and being new to the linux environment, I've been scratching my head for the last couple days. How can I fix this?

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  • How to effectively design a piece of software

    - by ti83plus
    Im a compsci student and ive got some experience in various languages and paradigms c/java/python/ruby/html/css/scheme/sql/asp(classic). I realise that i want to have some software in my portfolio for future job hunting even tho i still have 2 years left of my education. Ive got a pretty good idea of what i want to make, its a webapp. Most shops around here are either .net or java and since i know java best and dont have access to ms developer tools im thinking i should go with java. Even tho i feel i know the principles of OOP pretty good ive got no clue how to go from my idea to a working solution. Where can i access information about designing the underlying architechture of my solution? Also i would like to know what other technologies i should train on, my current list includes javascript(and possibly a javascript library) some sort of java web framework tips are appreciated. I would like to add support for android/iphone apps in the future and this is something i have to take into account when designing the app. I have done a course on software engineering but i found this to be more centered around project management ideas then the actual design and implementation. So i would like tips on technologies i should focus on to get the most out of my time without the massive overhead of huge config processes but at the same time keep my project viable in a business sense, so that i use technologies that are relevant for business (java developer jobs). And i would also like tips on where i can learn more about the design process around a software project, i will be working mostly alone. But i find the approach ive used up until now (start coding and figure it out as you go) wont suffice.

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  • Creating a SQL Azure Database Should be Easier

    - by Ken Cox [MVP]
    Every time I try to create a database + tables + data for Windows Azure SQL I get errors.  One of them is 'Filegroup reference and partitioning scheme' is not supported in this version of SQL Server.' It’s partly due to my poor memory (since I’ve succeeded before) and partly due to the failure of tools that should be helping me. For example, when I want to create a script from an existing database on my local workstation, I use SQL Server Management Studio (currently v 11.0.2100.60).  I go to Tasks > Generate Scripts which brings up the nice Generate and Publish Scripts wizard. When I go into the Advanced button, under Script for Server Version, why don’t I see SQL Azure as an option by now? The tool should be sorting this out for me, right? Maybe this is available in SQL Server Data Tools? I haven’t got into that yet. Just merge the functionality with SSMS, please. Anyway, I pick an older version of SQL for the target and still need to tweak it for Azure. For example, I take out all the “[dbo].” stuff. Why is it put there by the wizard? I also have to get rid of "ON [PRIMARY]"  to deal with the error I noted at the top. Yes, there’s information on what a table needs to look like in SQL Azure but the tools should know this so I don’t have to mess with it.

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  • How to get rid of 'grub rescue'?

    - by SaM
    While logged into Windows, I deleted a disk partition which was containing Ubuntu. When I restarted my pc, it is showing 'grub rescue' command prompt. How to boot windows now? I no longer require Ubuntu. I have Ubuntu live CD When I tried the following commend: sudo apt-get install lilo the following error is shown: Err http://archive.ubuntu.com/ubuntu/ natty/main lilo i386 1:22.8-10ubuntu1 404 Not Found [IP: 91.189.92.156 80] Failed to fetch http://archive.ubuntu.com/ubuntu/pool/main/l/lilo/lilo_22.8-10ubuntu1_i386.deb 404 Not Found [IP: 91.189.92.156 80] E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

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  • Can't single boot Ubuntu 13.04 64 bit

    - by stanleyhunk
    I'm new to Ubuntu, I bought an Asus A45VS laptop recently pre-installed with Windows 8, but I have already uninstalled it and wipef the whole HDD. I plan to install Ubuntu 13.04 64 bit on it. I have tried several times to install and uninstall Ubuntu again and again with boot-able USB, but it still fail to boot. All the installation process go fine, after rebooting my laptop, it just stick to the purple screen. Then I boot it with USB again, tried boot-repair, tried make an EFI partition, still the same. I have searched on the web, and all of them was about dual booting with windows 7 or windows 8, I don't wish to do dual booting as I wish to have single OS which is Ubuntu on this laptop. please help, thanks in advance.

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  • Picture lens doesn't find anything

    - by Han Cnx
    I get Facebook results, but nothing from my computer. If I open a terminal and use 'locate' then I can find stuff, but the picture lens is empty. Note that my picture files are on an NTFS partition. I have made a link named 'Pictures' in my home folder that points to the location where the picture files are. Again, this works with the 'locate' command and it also works for the Music lens, which is also a link in my home folder. It also (kinda) works for the Video lens, though it only wants to find videos I have opened, which seems not consistent with the other lenses. (and also not very useful this way)

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  • How to remove Ubunto from boot screen?

    - by Alaa M.
    I tried to install Ubuntu 14.04 on my Windows 8, and in the installation wizard I chose "Help me boot from CD". Now I have something like this when I restart the computer: http://i.stack.imgur.com/HxDQr.png If I click Ubuntu I get an error about a missing file (wubildr.mbr). I found a solution here. But that's not my concern now. I don't know if that means I have Ubuntu installed on my computer now or not, but I wanna delete it from the boot screen. I figured that I need to delete its partition, so I went to Disk Management and found the following: http://i.stack.imgur.com/W0oP4.png My question is: which one should I delete?

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  • Safely dual-boot XP and Ubuntu 12.04 Desktop?

    - by Ycart I
    My netbook Acer AOD255 has three primary partitions in it by default - PQSERVICE/recovery (NTFS), Android x86 1.6 (FAT32), and the main WinXP Home SP3 (pre-installed, dual-booted with Android from inside WinXP). I was able to resize all three partitions to give 9GB of unallocated space for a future Ubuntu installation, which can already be booted from a pendrive. Here's my problems: 1.) I don't know how to install Ubuntu on that 9GB space (even if I create an unformatted partition for it) 2.) I currently have no means of reinstalling my XP, or backing-up any data (so I don't want to accidentally wipe out my whole HDD at all) 3.) I want XP and Ubuntu to be dual-booted thru a boot manager like GRUB or something more practical (but google searches confuse me) 4.) When I boot to try Ubuntu, GParted displays my whole drive as unallocated space. It also says "can't have overlapping partitions" or something.

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  • Programming languages with a Lisp-like syntax extension mechanism

    - by Giorgio
    I have only a limited knowledge of Lisp (trying to learn a bit in my free time) but as far as I understand Lisp macros allow to introduce new language constructs and syntax by describing them in Lisp itself. This means that a new construct can be added as a library, without changing the Lisp compiler / interpreter. This approach is very different from that of other programming languages. E.g., if I wanted to extend Pascal with a new kind of loop or some particular idiom I would have to extend the syntax and semantics of the language and then implement that new feature in the compiler. Are there other programming languages outside the Lisp family (i.e. apart from Common Lisp, Scheme, Clojure (?), Racket (?), etc) that offer a similar possibility to extend the language within the language itself? EDIT Please, avoid extended discussion and be specific in your answers. Instead of a long list of programming languages that can be extended in some way or another, I would like to understand from a conceptual point of view what is specific to Lisp macros as an extension mechanism, and which non-Lisp programming languages offer some concept that is close to them.

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  • How to install Edubuntu on a system with low memory (256 Mb)?

    - by int_ua
    I'm preparing an old system with 256 Mb RAM to send it to some children. It doesn't have Ethernet controller and there are no Internet access at the destination. I've chosen Edubuntu for obvious reasons and modified it with UCK trying to minimize memory usage just to install, let alone using it yet. But Ubiquity won't start even in openbox (edited /etc/lightdm/lightdm.conf) because there are no space left on /cow right after booting. I've already deleted things like ibus, zeitgeist, update-manager (no network access after all), twisted-core, plymouth logos. I'm thinking about creating a swap partition on HDD, can it be later added to expand this /cow ? Is there a package for the text-mode installation which is used on Alternate CDs? I don't want to re-create Edubuntu from an Alternate CD. This behavior is reproducible in VM limited to 256Mb RAM.

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  • Nautilus uses different permissions for mounted drives

    - by farhad0011
    I've written two bash scripts to give read-only or read/write access to my NTFS partition: read-only access: sudo umount /media/Data_Drive/ sudo mount -t ntfs-3g -o ro,user,auto,nls=utf8,umask=0000,uid=1000 /dev/sda2 /media/Data_Drive read/write access: sudo umount /media/Data_Drive/ sudo mount -t ntfs-3g -o rw,user,auto,nls=utf8,umask=0000,uid=1000 /dev/sda2 /media/Data_Drive It works perfectly if I only use terminal to work with the files. It also works with Nautilus in read-only mode but not in the read/write mode. In fact, Nautilus gives me an error when I try to copy a file to Data_Drive saying "The destination is read-only". More funny, when I look at the permissions (by right-clicking on Data_Drive and then properties-permissions) I have all the required permissions to write a file in Data_Drive! I am so confused why Nautilus behaves strangely. I appreciate if anybody could solve the mystery!

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  • How do I get the Grub menu back after installing Windows on a separate disk?

    - by Shazzner
    Tried sudo grub-install on sda1 but it complained about being a BAD IDEA. I had to install windows for a work related issue so I used a separate disk (I had used it for ubuntu on this computer, but bought a bigger disk so installed ubuntu on that and left the old one in in case I needed an old file). Windows installed fine but overwrote Grub. So if I choose the Ubuntu disk to boot first in BIOS I get a blank screen. I googled and followed this advice: https://help.ubuntu.com/community/RecoveringUbuntuAfterInstallingWindows However, when I get down to this section: sudo grub-install --root-directory=/media/0d104aff-ec8c-44c8-b811-92b993823444 /dev/sda1 I get this: Attempting to install GRUB to a partition instead of the MBR. This is a BAD idea… --recheck does nothing. Any ideas?

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  • Big problem: Complete computer crash (no response when booted)

    - by Feratile
    I need your help: I installed Ubuntu 12.04 on my computer (I removed the complete system and installed Ubuntu instead) It said that the bootloader installation failed. So I chose the only partition that existed again. Installation succesful. Restart your computer. I did this. Then it went black when it rebooted (only a flickering stroke appears). No ISOs are executable. BIOS Boot Device Priority says: 1st Boot Device [SATA:PM-SAMSUNG HM] That was all I can say, please help me!

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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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  • Windows Repairs Itself After Ubuntu Boot

    - by pjtatlow
    I have a custom built computer in my home which was running Windows 7 primarily. After I installed Ubuntu 12.04 and upgraded to 12.10, Windows 7 has to perform startup repair after every Ubuntu boot up. For example, I am using Ubuntu for my everyday work, but when I switch to Windows to play one of my steam games, windows fails to boot, and it switches to the recovery partition to "repair windows" then boots windows. The whole process takes about 20 minutes, which is quite annoying. Anyone know why this is happening or what I can do? Thanks in advance!

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