On Sun, 28 Jun 1998 17:42:43 -0700 Michi wrote:

> I am having problems with my JTS Champion 2.5GB Hard Drive.  It now is
> telling me to insert a boot disk because my hard drive is not bootable.
> I checked the wiring and the BIOS info and everthing seems to be normal.


You didn't say what OS you're on, so I'll be kind of generic, which
means
a long post. I'll assume you're NOT on some form of disk compression --
I hate data recovery from compressed disks. Knowing the exact error
message would help also. Have you determined you don't have a virus?
Virii can cause boot problems.

You'll need some kind of disk utility such as nuts & bolts, Norton
Utilities, etc. -- there are many good ones. Read the manual first,
please. I've used Norton the most, but the latest edition of nuts &
bolts is really good. There generic utilities with dos like chkdsk, but
the 3rd party stuff can be more robust.

Start with a bootable floppy disk. It needs to be the same DOS as the
ailing C: drive -- from your message it's obvious the ailing drive is
your C: drive.

Generally speaking you always start with a disk diagnostic such as
chkdsk or Norton Disk Doctor, etc. Work from a floppy. You may have to
make several passes -- the manufactor of the drive may have a setup
utility that catches the problem. As another thread on this list found,
sometimes one utility may work when another doesn't. If the diagnostic
can fix the problem, you're fortunate. It should at least give you a
clue.

Two major reasons for working disk to become unbootable.
1) Corruption of IO.SYS and/or MSDOS.SYS for MS-DOS; IBMBIO.COM and/or
IBMDOS.COM for PC-DOS
2) Absence or corruption of default command processor like COMMAND.COM
or it's 3rd party replacement -- NDOS, etc.
The error message you get may be something like Missing COMMAND.COM.
You'll need to replace what's wrong with the requisite file from the
same version of dos as on the ailing disk. The disk should then boot.

A third, more rare cause is when the Partition Table section called BOOT
is modified to NO.

In your case, the diagnostic may indicate a problem with the Partition
Table and/or Master Boot Program. This is where you need to be really
careful.

Using some form of all-purpose sector editor, like Norton Disk Editor,
at your level of experience, stay away from the Media Descriptor Byte --
it's what tells DOS what kind of media type you have -- if you
accidentally screw all 3 copies up, you have a door stop instead of a
hard disk. (For later, practice on floppies, then discarded hard
drives.)

With your manual in hand, (Disk Doctor, etc.) start the sector editor
program -- from the floppy -- go to the DRIVE you want to make bootable,
do what the manual says to get to PARTITION TABLE under the heading
SYSTEM it'll say BIGDOS; next to it should be BOOT. If BOOT says NO,
change it to YES and write it to disk. The computer should now boot up.
If BOOT says YES, read on.

Every hard disk for dos has a TRACK 0 (zero). The precise BIOS address
is cylinder 0, side 0. This is where the Master Boot Program lives. If
cylinder 0, side 0 becomes unreadable for any reason, DOS cannot mount
the disk.

If this is your problem, you need to write a valid Master Boot Program
to this sector, then use your disk diagnostic (Disk Doctor) to rebuild
the partition table.

>From DOS 5 on, there's an undocumented feature in FDISK  /mbr (that's
for master boot record) Do you have FDISK on your bootable floppy? If
not, get a floppy that has same version of DOS as ailing disk of FDISK.
(Don't use DOS 6.0 for a 95 machine!) the command line syntax is
fdisk /mbr.
(Make sure you FDISK the C: drive, not the floppy.)
You have succeeded if DOS does NOT return an error. Now use your disk
diagnostic (Disk Doctor) to rebuild the Partition Table. The computer
should now boot.

The process is more involved copying the Master Boot Program from
another computer with the same OS as the ailing system. I'll assume
you're not on DOS 3.3 or 4.0. If so SIGH, let me know. As a last resort
DOUBLE SIGH you can write a generic Master Boot Program -- if you need
one, let me know.

Best regards,
Jim Griffin

--
Prometheus was the first Beta Tester.
Sisyphus was the Corinthian Systems Administrator.