Retrieving data from SCSI hard drives
May 1, 2006 5:58 PM   Subscribe

I have 2 SCSI hard drives I need to retrieve data from.

I had a computer that stopped working. I would really like to get the data off the drives, but I haven't worked with SCSI hard drives before. I got an Adaptec AHA-3940UW SCSI controller, put it into my extra computer (running WinXP) and plugged one of the drives in. The controller recognizes the hard drive but I get an error of Operating System Not Found. Now, this computer often says this message, but I just need to reboot to make it go away. That isn't working with either of the SCSI drives plugged in. I would really like to just use the extra computer as usual and have the SCSI drives show up in My Computer as 2 more hard drives. Is this possible? Any help is appreciated.
posted by disaster77 to Computers & Internet (8 answers total)
Hit control-a during boot. Configure the SCSI controller not to load its BIOS. That should let your normal boot device come up.
posted by majick at 6:04 PM on May 1, 2006

That is absolutely possible. It sounds like either you're having a more fundamental problem with the motherboard (The Operating System Not Found error occurring without the card plugged in would seem to indicate this) or the BIOS is trying to boot off the SCSI controller. If the latter is the case, you can probably tell the BIOS to ignore external controllers. Check out what the boot order is set to.

Also, though it's probably not the issue you might want to install the drivers before booting with the card attached though it's unlikely that there would be problems from not doing this.
posted by joegester at 6:05 PM on May 1, 2006

I think that the computer bios and the SCSI board bios are trying to boot off the SCSI drive instead of the normal drive. That can be controlled by various bios choices, but exactly which ones, and which bios they're in, depends enormously on what you've got, so you'd have to figure it out for yourself.

For instance, in the bios of my HP workstation, there's a section where you can enter devices from which to boot, and the order in which they should be checked.

I'm not so sure that Majick is right. (I'm also not sure Majick is wrong.) Disabling the SCSI bios may also prevent the card from checking the SCSI chain, and might result in the drives not being considered present when Windows finally boots up, in which case those drives would not become available to Windows.
posted by Steven C. Den Beste at 6:18 PM on May 1, 2006

The Operating System not found error was there before I attempted the SCSI retrieval project. It's just my old computer that is in tough shape and I use it for messing around.

So I got a different computer and put the card in and attached one drive and Windows started up. Windows says it found the controller, but I still don't see the hard drive. Any suggestions?
posted by disaster77 at 6:41 PM on May 1, 2006

Double-check that the drive shows up in Device Manager. If it does, you might have to go into Computer Management (Control Panel -> Administrative Tools), select Disk Management, and assign the drive a letter.

If it doesn't show in Device Manager, uhh... I dunno.
posted by neckro23 at 7:08 PM on May 1, 2006

It doesn't show in Device Manager. Argh. Thanks for your help though.
posted by disaster77 at 7:11 PM on May 1, 2006

search google by the drive model #'s and make sure you don't have the drives set to the same scsi ID number. Older scsi drives typically have jumpers on the front that allow you to assign a number from 1 to 7 to the drive.
posted by freq at 8:25 PM on May 1, 2006

Or just plug them in one at a time, avoding ID issues, unless the SCSI drive is set to the same ID as the host adapter.

However, you need to terminate the bus correctly. The ideal way is to terminate at the end of the cable. If you cable has a dangly bit at one end that isn't a connector, then that's a terminator.

When it boots, you should see a message from the SCSI bios, and it'll mention that you can hit CTRL-A, which will bring you to the SCSI bios on that host adapter. Do so. If you see a message that says "Adaptec" but nothing about CTRL-A, hit CTRL-A anyway. Make sure termination is enable on the card. Matter of fact, for troubleshooting, finding the "Reset all to default" is a really good idea.

If you don't have a terminator at the far end of the cable, you'll need to have the last drive on the bus terminate the bus. On narrow scsi (50 pin) devices, this is commonly a jumper, occasionally, on older drives, there was a resistor pack you had to install. If the last tech didn't suck, he taped them to the drive.

Wide SCSI (68 pin) almost always terminates on the cable, if not, it'll be a jumper. Google up your drive's model number, most of the data sheets are on the web. If the jumpers are labeled, and many of them are, the common labels are ID0 ID1 ID2 ID3 (Drive ID, binary, all off is 0, all on is 16, narrow drives won't have ID3.) TERM (Termination enabled.) TPWR (Termination power, usually suppllied by the host adapter, thus, leave this one off) STRT (Start Motor, usually off, used by large arrays to start the drives in order, most HAs send the SCSI start command) SYNC (used by large arrays to sync the spindles, usually off) and finally LED (A drive busy LED, no jumper here ever, most people just use the Host Adapter for the drive LED hookup.)

If they are labeled, jumpering is simple. Jumper one drive on ID0, the other on ID1. Leave ID2/3 open on both. Jumper TERM on the drive on the far end of the cable.

Watch the boot, in particular, the Adaptech Bios. If it is enabled, you should see it scan the bus and identify the drive or drives. If it does, there's hope.

Now, plug in one drive, boot to windows. Check the device manager (under the system control panel.) Make sure the SCSI controller is listed and has a running driver. If not, install the correct one. If so, then check under disk drives, you should see a drive. If so, run Disk Administrator (under Admin Tools/ Computer Management) and run the "Rescan Drives" action.

You may get a message about writing a signature to a drive. This is okay (and a good sign.) Let it.

Now, if the drive has a recognizable partition and format, you'll see a drive appear. Assign it a letter, if it didn't pick one. Log out and back in, and you should be able to read the drive.

Once you have the data off, repeat with the other drive. Once both are backed up, you can cable them both up, making sure they're at different IDs. Once the BIOS scan shows this, then Windows should find both drives.
posted by eriko at 5:52 AM on May 2, 2006

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