Hard Drive Detection In Bios

[jonathankeeping]

Hi there...
Over the last few days some very strange things have happened to my PC. I've got a Maxtor 17GB which used to register fine in the BIOS as LBA. I then brought a IBM 15GB which would only register as a 2GB under LBA. For the BIOS to recognise the HD properly, I had to set in as Normal or CHS. It then recognised the IBM fine. Since then I added another 128MB RAM which when fine. I then tryed to install Win NT, but it didn't like my partiton structure. Next thing I know, my Maxtor 17GB is now registering as a 2GB drive under LBA mode!!! The only way I could get the drive to register back to a 17GB was to change the mode to normal (CHS). Of cause that stoped my from accessing my data properly, so I've spent the last two days trying to put everything back. I now have my both HD's running as CHS.

Two questions arise...

Why did this happen?
Whats the difference between LBA (Linear Block Addressing) and CHS (Normal)

Any help you can provide would be greatly appreciated.

-Jonny

[tbhoover]

Check the jumpers on the IBM drive. I have a 20.5GB 34GXP which has jumper settings to force it to 2GB.

[jonathankeeping]

Hi Axel,
Well... I think I can finally say I've got everything sorted http://www.sysopt.com/forum/smile.gif!!! My Maxtor is now back in working order with three bootable partions Win98, RedHat and a spare one. I had to remove all partitions, and do a low level format.

It's the second time I've learnt this lesson. About a month ago I installed Corel Linux. I made sure it installed to the correct partion, but it still somehow managed to mess my other partions up http://www.sysopt.com/forum/frown.gif Since then I've kept all my data on the IBM drive. I'm so glad I did, or I'd have lost it all over again!!!

I've now got NT4 installed on a spare 6.4GB HD. It was a clean HD and NT installed just fine. I will hopefully just copy this partion to my other drive, and everything will work just fine http://www.sysopt.com/forum/smile.gif

As for BIOS addressing, I now have to run both my drives in Normal (CHS) mode for there correct capacity to register in the BIOS. I have the most recent BIOS version so I'm not too sure why I can't use LBA. Anyway, everything appears to be working fine now, so if it ain't broke don't fix it!!!

-Jonny-

[Axel]

I had exactly the same problem during a bad install of NT terminal server -

It has a lot to do with the NT install wanting to partition the drive for you and the choices you make while loading the operating system -

NT installs can be evil on existing files -

I've found it's absolutely best to wipe any drive you plan to load NT on after saving any desired data.

Later - you can slave an existing drive into a stable NT environment - that's a LOT easier than loading the OS in the hopes the data on a drive will remain intact.

As for your data - in my experience, I lost it all and just ended up doing a low level re-format and fdisk. One of the three drives ( and this one was brand new out of the foil bag ) was rendered into a door stop by the failed NT install. It was a 1.7 GB maxtor I had laying around that was actually a warranty replacement from 2 years ago. I suspect it might have been a factory rebuild job that just picked it's time to die....

Let us know how it turns out for you. Once you change the BIOS addressing of a HD, I haven't had much luck with anything on the drive from before the change.