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>>>
>>> This is the point: Your HD has a probability of being misrecognized by
the
>>> BIOS.
>>>
>>>
>>>> My much newer 100GB HD works badly on two computers, including the one
>>>> where I partitioned it, so I think it is a HD problem.  But maybe DOS
is
>>>> confused by 100GB.  All of the linux partitions act normally.

>I zeroed out the entire drive with a Seagate/Maxtor hard disk utility on
>the Ultimate Boot CD, and repartitioned with BL3 fdisk and mke2fs and DOS
>format.  sys'ed it.  It still acts the same as when I used PQMAGIC.
>Won't boot (I can boot to floppy disk and cd to it) on two computers.
>I think yesterday it was booting on the third computer (but D: and E: were
>full of gibberish).

These are sympthoms of bad zero tracks!

>Several other drives boot on both of them, but one 10GB Maxtor will boot
>on one and not on the other and PQMagic is happy with it on one computer
>(where linux and DOS work but XP and Win98 both crash quickly) and not on
>the other (error message about partitions and drive geometry). An 8GB WDC
>with Easy-Drive won't boot and the other needed the partitions redone
>before it would boot.  This stuff was all free.

>Linux won't mount the two logical DOS partitions that fdisk made.  If I
>copy files to those partitions via DOS laplink pro, they turn into
>gibberish.  The programs in C: work so I will enlarge C: and put all my
>DOS programs in it.

>Linux works fine once I boot to it from DOS.  LILO stops at LI
>when booting from lilo on floppy disk.  I doubt it would work from MBR.

>The solution is to boot from DOS floppy disk to DOS, and then with loadlin
>to linux.  I can't use this drive in the ECS computer where loadlin stops
>the linux keyboard from working.  Is there some other way to boot from DOS
>to linux?

ECS manufactures  the same Pc Chips motherboards, with other names.
Many Pc Chips MBs are known for conflicting with Linux somehow.

>Any idea why linux behaves so much better than DOS in logical partitions?
>Sindi

At this point I can affirm that your HDs surely have bad "zero tracks",
which are not fully damaged but won't boot.
However they can be useful for a second drive (for data storage).
DOS is extremely zero-track dependable because it keeps the system files
strictly there, while Linux doesn't.

>>> Fdisk. cfdisk, qparted, etc. are unable to handle this kind of viruses.
... ... ...
>>> (edited for short)
>>>

>I used the Maxtor utility.  I think the partition table area is worn out.

That's why I say your HD have bad zero tracks.

>>
>> To erase (overwrite with zeros) the MBR I can also
>> dd if=/dev/zero  of=/dev/hda  bs=512  count=1
>> Would this be just as good?  Can I then repartition and reformat?
>> Should I overwrite more than this in case the virus is hiding some place
>> else?
>>

I do believe this will work fine and makes the same debug does (and its more
concise).
The focus is the master boot record.
Sparse bad sectors on other tracks don't affect the booting.

>>
>>> After typing   debug <enter> enter the following values: ... ...
>>>
>> Might this do permanent damage to the MBR if I do it wrong?

It doesn't cause any damage, but just erases the MBR.
You can redo it in case of any error.
Naturally all the data will be lost.

>>
>> -F  200  L1000  0 ... ... ... (edited for short)
>>
>> Having done this, you'll have a "brand new" HD what is to say you have
>> to partition, format, mount, etc.
>
> I have practice doing that.  Nothing important on the drive.
>
> I found a site warning against using FDISK/MBR, which can cause more
> problems than it cures.
>

FDISK/MBR is a poor solution, and has to be done from a floppy known as
"free of viruses".
If you aren't very sure of this, really don't use it.
This option just replaces the HD's MBR with  the floppy disk's one.

>
> Would spinrite be adequate to determine if the drive is simply worn out?
>

I'm not sure. I've never used it.
>
Since zero-track is much more sensitive to failures, I think HD
manufacturers should provide some kind of adjustment so that track zero
could be "pulled" to another location, but unhappily this doesn't happen.
Naturally this would change the geography of the HD.

>>
 Teixeira