Mail Archives: opendos/2000/10/29/21:36:20
Pat,
Since you have been around since Bill Gates was in grade school, it is
funny that you don't know why the last cylinder of the HD was left out by
the MSDOS FDisk program. Back in those days the hard disks heads
stopped anywhere they were at when the computer was powered down, and
they bounced and scraped along on your data. That's why the Park program
was written, so the heads would travel to the last (unused) track on the
last cylinder and any damage would not cause any damage to the usable
parts of the disk.
In some cases, there was some diagnostic data put on the disk by the
manufacturer and this was put on the last cylinder. I believe I read
that in one of my ancient (circa 198x) Peter Norton books.
On Sat, 28 Oct 2000 21:27:44 -0600 "Patrick Moran" <pmoran22 AT yahoo DOT com>
writes:
>
<SNIP>
> Ever since I
> low level formatted my first hard drive (Seagate ST-251) I could not
> find
> what happened to one missing cylinder. I still don't know why it
> cannot use
> it, but I finally found it and it is the last cylinder.
>
> I don't recall of having this problem when FDISK formats a
> partition. I have
> used partition sizes from a couple of megabytes to over 1GB and have
> not
> seen a problem. Norton's and PCTools diskeditors show the BPB as
> being
> correct. Of course I am talking about DOS 5.0 and later. Earlier
> version did
> not use all of the information in the BPB and show up as junk.
<SNIP>
There was also the floppy drive thing where you could write to a 720k
disk and format it as a 360k disk with the old 2.11 DOS. You could read
the full 720k but not format the disk as 720. In later DOS versions you
could still format a 720K disk as 360K but were also able to format them
to 720k. I believe that was because IBM had not yet included the 720k
capability in the BIOS until the AT was put out with 720K disks. I don't
remember if it was 3.2 or 3.3 DOS which came with the AT.
There were also a lot of people about that time who cut an extra hole in
360k to make the computer think they were 1.2Mdisks and 720K disks were
punched or drilled or burned to make the computer think they were 1.44Meg
disks. There was a lot of stuff written in computer mags about data loss
due to bad media on the reverse side of the disks, and there was also the
problem of all those little microscopic bits from the drilling and
punching operation getting caught by the heads and destroying data. I
tried the 360k to 1.2Meg and used good BSF and Storage Master DSDD disks
but I found out over half of my disks couldn't hold data on the back
side. About 1993 the price of the 1.2Meg/1.44Meg disks dropped a lot ,
so it didn't make sense anymore anyway.
Now I just buy my disks pre-formatted and never worry about it again
unless I have to use Nortons Clean program on a diskette.
<SNIP>
> > BPB - these diskettes are unreadable on DOS 3 and up.
>
> Are you saying that DOS 3.0 and later cannot read diskettes
> formatted with
> earlier DOS? If so, that is not true. I can still read and have been
> able to
> read those 160K single sided 5-1/4" floppies formatted with DOS 1.0
> and DOS
> 1.1. The very first version of DOS I used on my first PC was Tandy
> DOS 3.2.
> I used DOS 3.3 when I installed my first hard drive. I could and
> still can
> read the "Inside the IBM PC" by Peter Norton which consists of to
> floppies.
> One is a flippy (a term coined when using a double sided floppy on a
> single
> head floppy drive, you just FLIP the floppy over and read the other
> side.)
> and one single sided floppy. Both disks use the 160K format with
> only 8
> actual sectors per track. Not the later floppies that were formatted
> with 9
> sectors but only used 8. I can still read my DOS 1.0, 1.1, 2.0, 2.11
> DOS
> floppies.
>
> I have even seen floppies with that area (BPB) totally corrupted and
> still
> read the diskettes.
>
<SNIP>
You do have a lot of good knowledge and I have read most of the same
stuff in my DOS manuals and in Upgrading and Repairing PCs by Scott
Mueller and in PC Upgrade and Maintenance Guide by Marki Minassi.
I do really enjoy the traffic on the site but I wish the FLAMES could be
cut down a little. Those FLAMING should remember that you should always
use UPPER CASE when FLAMING. I also prefer "Expletive Deleted" or
"Nixonism" to "C***" and other such annoyances, although there are over
150,000 other english words that could be used.
Regards;
BOB "DOMAN' MOSS "Chocolate is a vitamin"
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