"Arno Wagner" wrote in message
Previously wrote:
Hello!
I have a strange question about an old hard drive that I pulled out
of an old Pentium 1 computer. The hard drive was working fine, and
the computer was able to boot into Windows 95 fine.
Then I decided to run SpinRite6 to check if the hdd had any bad
sectors. SpinRite6 booted fine from a diskette and detected the
drive. Then it refused to do any kind of work from the drive and
claimed that the partition size was larger than the drive size
indicated in the computer bios.

SpoinRite is old and completely irrelevant for ATA disks.
Do not use it.

Ignore the idiot babblebot.


The drive is a Western Digital caviar and its label indicates that it
has 2484 cyl; 16 heads; 63 sect; 1281.9 MB.

http://e.271828.p.31415.googlepages.com/s_IMG_2558.jpg

The computer auto-detected the drive as following: 2484; 16; 63; 1223 MB.

That is the default translation as found in the drive's identification sector.

This configuration was able to read the drive fine, but SpinRite
gives this:
http://e.271828.p.31415.googlepages.com/s_IMG_2561.jpg

Then I pulled the drive and stuck it in a newer Pentium 4 computer and
it detected it as follows:
cyl :620; hds: 64; sectors: 63. Total sectors 2502872

So now the question becomes: what CHS is used in the drive's MBR.
If that's the same as above than the bios isn't doing any translation
and forces the 620 : 64 : 63 CHS translation on the drive.

Spinrite ran fine.

When I stuck the drive back into the old computer I tried this
configuration and got 1221 MB.
http://e.271828.p.31415.googlepages.com/s_IMG_2560.jpg

The computer also booted up quite fine and made it into windows.
Spinrite still did not want to run on it and claims that only 619 cyl
are specified.
http://e.271828.p.31415.googlepages.com/s_IMG_2562.jpg
What is going on?

I have extensive experience with modern hardware, but this is my first
experience with such old hardware.

Can somebody please explain or clarify what is going on: How can the
harddrive be detected fine with 2 different configurations, which one
is the correct one, and why does Spin Rite read the drive on the newer
computer but refuses to read it on the old computer with either of the
2 configurations.


Drive geometry is done by the BOS for ATA drives.

Nonsense. It does it for any drive.

It has no relation to the real disk geometry.

Different BIOSes may use different CS translation.

Because you either tell it what to use or it makes a calculated guess
according to what it finds on the drive (default translation or MBR).

The way to deal with this is to use LBA mode.

Which is what the P4 does. CHS is not used so setting doesn't matter.
Apparently the P1 doesn't have Int13 extensions and has to deal with
CHS and the correct setting obviously matters there.
I'm betting that the drive was partitioned with the cyl 620; hds: 64;
sectors: 63 setting.
Apparently that is bigger than the drive is, according to the P1 BIOS.

Sounds like the P1 bios may be limited. You could try modifying the
cyl value in MBR and see if that satisfies SpinRite.


That SpinRite does not deal with it is a limitation of SpinRite.
I advise to stop using it.

Ignore the babblebot moron.


Arno