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Another hard drive question

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I just installed a 1TB Western Digital hard drive. I already have to 500GB hard drives and they appeared as HDA and HDB. Common thinking would say that this new one should appear as HDC, but, it has made its presence shown as HDB and the old HDB is now HDC. Why did this happen? Before I start doing anything that could result in serious hard drive/partition problems are the OS's that were/are on the old HDB which is now HDC still selectable or am I going to have to make some entries in my grub bootloader menu to reach them?

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Update,, even though the old HDB is now listed as HDC it seems to have no effect on the different OS partitions, I just selected Win 7 which is located on (hd1,0) and it booted right up.

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What type of hard drives are these? Internal? External? USB? SATA? EIDE? etc. What they are affects how BIOS determines what to call them.

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[quote name='longgone' post='323757' date='Apr 19 2011, 04:52 PM']All three are SATA, two are Seagate @ 500GB each and one is a Western Digital @ 1TB. They are all internal.[/quote]In that case, it's probably due to the way you connected them on the motherboard. [s]Depending on the motherboard, some manufacturer's have the SATA ports enumeration starting with zero (0) or one (1). If you plugged the first HDD into the 1st one, it would show up as HDA, and the new 1 TB drive is probably connected to port 2, thus showing up as a HDB.[/s]After having re-read my reply, I don't think I explained that clearly. Let me rephrase.If your motherboard manufacturer has SATA ports enumerated 0 through 5 (for example), the drive that is connected to port 0 would be the first hard drive that the BIOS recognizes and therefore would be displayed as HDA. If however, you plug in a hard drive into port 2 (on the motherboard), it would be displayed as HDC. I hope that explains it better without adding any confusion. Edited by Tushman

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I wish it were that easy, but, the data cable was plugged into the next available slot, so, I was under the impression that it should appear as HDC. I guess a real test will be with the install of an OS on it and see where it turns up at.

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I am guessing that your MOBO has 4 SATA sockets.What probably happened is that your old ones were plugged into SATA 0 and 2. Since SATA 1 was empty the bios and OSes saw them as HDA and HDB.When you plugged the new one into the next available slot it was probably SATA 1. The bios and OSes would see them as you now describe even though you did not change the data cables around.

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I'll double check the cables/slot numbering as I have had to unplug in the past when I installed Win 7 on HDB. This board has 6 SATA ports on it.

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[quote name='amenditman' post='323773' date='Apr 19 2011, 07:05 PM']I am guessing that your MOBO has 4 SATA sockets.What probably happened is that your old ones were plugged into SATA 0 and 2. Since SATA 1 was empty the bios and OSes saw them as HDA and HDB.When you plugged the new one into the next available slot it was probably SATA 1. The bios and OSes would see them as you now describe even though you did not change the data cables around.[/quote]Dale, [b]amenditman's[/b] response here is pretty much what I was saying in my previous post. Just phrased in a slightly different way. I hope what I said earlier makes more sense now.

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[quote name='longgone' post='323778' date='Apr 19 2011, 08:51 PM']I'll double check the cables/slot numbering as I have had to unplug in the past when I installed Win 7 on HDB. This board has 6 SATA ports on it.[/quote]Dale,It is possible that the slots on the motherboard do not correspond to the numbering assigned by the linux kernel. A could be B, etc. Just depends on how the system is initialized by the kernel. This is just a theory.Adam

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[quote name='ross549' post='323803' date='Apr 20 2011, 04:09 AM']Dale,It is possible that the slots on the motherboard do not correspond to the numbering assigned by the linux kernel. A could be B, etc. Just depends on how the system is initialized by the kernel. This is just a theory.Adam[/quote]If you look in the BIOS, you will have an option the set the HDD boot order. The default should, and notice I said should and not will, be the order of the cables. But you can change that order and that should change the drive letters in grub.BTW, the fact that the drives letters and numbering can change is the reason grub2 uses the UUID numbers instead. Edited by lewmur

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Well, in the BIOS, all appears to be good SATA 1 & 2 are both the 500GB Seagate hard drives and SATA 3 is the Western Digital hard drive. Visual check and the first hard drive is plugged into the SATA 1 slot, second one in the SATA 2 slot, etc. This box does have some strange setups though. In the boot order priority entry I cannot for the life of me get SDA2 to come up as the third boot device. First boot is the DVDrom, second is the SATA1 disk third is the 9 in one unit and fourth is something from Realtek which I have no idea what it is. But the bottom line is I can't get rid of either one of the last to entries. So, I am going to guess that this might have something to do with the OS itself.

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[quote name='longgone' post='323884' date='Apr 20 2011, 02:22 PM']Well, in the BIOS, all appears to be good SATA 1 & 2 are both the 500GB Seagate hard drives and SATA 3 is the Western Digital hard drive. Visual check and the first hard drive is plugged into the SATA 1 slot, second one in the SATA 2 slot, etc. This box does have some strange setups though. In the boot order priority entry I cannot for the life of me get SDA2 to come up as the third boot device. First boot is the DVDrom, second is the SATA1 disk third is the 9 in one unit and fourth is something from Realtek which I have no idea what it is. But the bottom line is I can't get rid of either one of the last to entries. So, I am going to guess that this might have something to do with the OS itself.[/quote]Your BIOS probably has two settings. The first is the Boot devices order, which is what you described. CD, HDD, USB/Card Reader and finally the network card. But in addition to that setting, there should be one for the HDD drive order. That is the one which determines hd0, hd1 etc.

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Correct, that the HDD order is where I got the info from in regard to the order in which the HDD's are listed/seen by the machine.

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[quote name='longgone' post='323884' date='Apr 20 2011, 02:22 PM']....This box does have some strange setups though. In the boot order priority entry I cannot for the life of me get SDA2 to come up as the third boot device. First boot is the DVDrom, second is the SATA1 disk third is the 9 in one unit and fourth is something from Realtek which I have no idea what it is. But the bottom line is I can't get rid of either one of the last to entries. So, I am going to guess that this might have something to do with the OS itself.[/quote]Dale,The BIOS software is responsible giving the choice of boot up priority menu. The OS in this particular case has nothing to do with how the BIOS is displaying those choices to you. Although I am a little surprised that it won't let you change the last two items - I guess it's not entirely out of realm possibilities. I have seen a few OEM systems (Like HP & Dell) that come with their own OEM designed BIOS overlay. You could always check on the manufacturer's website to see if there is a BIOS flash update available. Before you do that, I would encourage you to take a 2nd look to see if there is a way to change it. Usually you can change those items using the page up/down or the plus/minus sign on the keyboard to change the value or menu item in question.I also don't understand what the problem is now. You say the operating system sees all 3 HDDs just fine. .... so are you trying to solve a boot up issue? I know that you like to dual-boot with Windows & Linux. Are you just trying to change the OS menu choices? Are you using GRUBB and need to change the boot priority? If you're able to bootup to both operating systems just fine, then I don't think the issue of HDA; HDB; what have you, will be an issue. Edited by Tushman

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[quote name='longgone' post='323895' date='Apr 20 2011, 03:27 PM']Correct, that the HDD order is where I got the info from in regard to the order in which the HDD's are listed/seen by the machine.[/quote]You can also change that order.

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Under the boot device priority selection in the BIOS I have the 4 options I mentioned earlier. On the side bar it also says that the selections in brackets, which all four of those options happen to be in cannot be changed unless changes are made in the previous menu (what this previous menu is I have not a clue) the selection in the BIOS prior to the boot device priority is the "Power" selection. I'll check the BIOS again and see what I can figure out.Now the problem, I think. At the moment, the two 500GB hard drives are being seen as SD0 and SD2 and the new 1TB is being seen as SD1. Prior to the "new disk" install, they were seen as SD0 and SD1. After the install of the new disk the old SD1 is now SD2 and the new disk has replaced it at SD1. I just installed Debian 6.0 on the new disk in partition 1 80GB in size. I could not install the boot loader to the partition I had just created on the new disk. I tried both (hd2,0) and (hd1,0) neither of which worked, so for the moment Debian has no boot loader installed.One note to mention is that on the 500GB hard disk that used to be listed as HD1, I have Win 7 installed on the first partition and I can select it and boot into it from the boot loader menu.I hope I did not muddy this up more than it is already.

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[quote name='lewmur' post='323892' date='Apr 20 2011, 04:10 PM']Your BIOS probably has two settings. The first is the Boot devices order, which is what you described. CD, HDD, USB/Card Reader and finally the network card. But in addition to that setting, there should be one for the HDD drive order. That is the one which determines hd0, hd1 etc.[/quote]You know, Lew, I'm having similar issues with drive nomenclature right now --> [url="http://forums.scotsnewsletter.com/index.php?showtopic=44699"]http://forums.scotsnewsletter.com/index.php?showtopic=44699[/url] <-- and I've NEVER seen anywhere in any recent BIOS that I've used where you can force BIOS to identify the drives in some other order than how they are PHYSICALLY installed on the SATA or EIDE channels on the mobo.Please elaborate.

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Quick update on this ,,, I booted up my Mandriva install and under the configure your computer icon I selected the hard disk entry and it has the hard drives listed just like they are in PCLOS. SDA is a 500GB hard drive, SDB is the new 1TB hard drive, and SDC is the other 500GB hard drive (formerly known as SDB).

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[quote name='V.T. Eric Layton' post='323913' date='Apr 20 2011, 08:03 PM']You know, Lew, I'm having similar issues with drive nomenclature right now --> [url="http://forums.scotsnewsletter.com/index.php?showtopic=44699"]http://forums.scotsnewsletter.com/index.php?showtopic=44699[/url] <-- and I've NEVER seen anywhere in any recent BIOS that I've used where you can force BIOS to identify the drives in some other order than how they are PHYSICALLY installed on the SATA or EIDE channels on the mobo.Please elaborate.[/quote]Unfortunately there are no set rules on what features are in any given BIOS but as far back as the early IDE days there has been a feature that allowed you to "swap drives". How it is implemented in your BIOS I have no idea. But I can almost guarantee you can change which drive's MBR is used to boot. That will also change which one is hd0 vs hd1 or HDA vs HDB or sda vs sdb. In BIOS's with separate "boot order" and "harddrive order" features, you can normally set the order of your SATA drive and make any one of them sda, sdb, sdc etc. Other BIOS's just list all of the HDDs in the "boot order" listing. But you can still move them around to set there order. And doing so will change which one is sda, sdb and so on. Edited by lewmur

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Also, remember that most modern implementations of Linux and GRUB use the UUID of the hard drive to determine which one to boot. This solves the problem of having to update device numbers in configuration files when drive orders are changed. The downside of this is that if you change the physical drive but keep the same installation you have to manually update the UUID, although I'm sure there's a way to autoupdate that in the GRUB console.

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[quote name='Peachy' post='323952' date='Apr 21 2011, 08:07 AM']Also, remember that most modern implementations of Linux and GRUB use the UUID of the hard drive to determine which one to boot. This solves the problem of having to update device numbers in configuration files when drive orders are changed. The downside of this is that if you change the physical drive but keep the same installation you have to manually update the UUID, although I'm sure there's a way to autoupdate that in the GRUB console.[/quote]See my post #11

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[quote name='lewmur' post='323950' date='Apr 21 2011, 09:02 AM']Unfortunately there are no set rules on what features are in any given BIOS but as far back as the early IDE days there has been a feature that allowed you to "swap drives". How it is implemented in your BIOS I have no idea. But I can almost guarantee you can change which drive's MBR is used to boot. That will also change which one is hd0 vs hd1 or HDA vs HDB or sda vs sdb. In BIOS's with separate "boot order" and "harddrive order" features, you can normally set the order of your SATA drive and make any one of them sda, sdb, sdc etc. Other BIOS's just list all of the HDDs in the "boot order" listing. But you can still move them around to set there order. And doing so will change which one is sda, sdb and so on.[/quote]Hmm... I have four different machines that I have access to here currently. They are different ages and different BIOS manufacturers. None of theme allow the reordering of device assigned numbers [i]other than[/i] by physically moving them from one channel to another on the motherboard. Also, changing boot device order does NOT change the device's BIOS assigned device number.I've been going round and round with this Arch GRUB thing for a while now on numerous forums and newsgroups. From all I've read, researched, and learned I'm going to have to disagree with your assessment of how you can change devices within BIOS.When you fdisk -l from within a Linux distribution, the output you see is how udev and/or hal sees the devices. When GRUB (regardless of which drive it is on in the system) initializes, it gets the device assignments from the BIOS. You can force GRUB to map devices on its own, in case you have a buggy BIOS that doesn't provide proper information to GRUB (I'm talking GRUB Legacy here, by the way).Anyway... I don't claim guru-ness in this area either, so I'll just have to consider the information you provided and file it away some where for later confirmation or debunking. I'm not saying you're wrong, Lew; I'm just saying that I don't find it to be that way in my experience. ;)Later...

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[quote name='V.T. Eric Layton' post='323984' date='Apr 21 2011, 01:54 PM']Hmm... I have four different machines that I have access to here currently. They are different ages and different BIOS manufacturers. None of theme allow the reordering of device assigned numbers [i]other than[/i] by physically moving them from one channel to another on the motherboard.[/quote]We may be having a problem with terminology here. I'm not saying there is a setting in the BIOS that says "make drive x hd0". I'm saying there is one that "list" the drives detected and lets you move the drives up and down in the list. Then, when the computer boots, that will be the order in which grub or ntldr detects them. If you want, I can send you pictures of the settings in my current desktop. And EVERY BIOS I've come across in the last few years has some such feature. Edited by lewmur

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