Bulk Erase 8" floppies

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Wed Sep 17 13:51:00 2003

On Wed, 17 Sep 2003, Tillman, Edward wrote:
> If you happen to have an old x86 laying around (286sx - 486dx), with DOS 5
> or earlier, your format command will tell you the types/capacities of
> floppies available, and the switches required to format them properly. A

Other than AFTER-MARKET add-ons, the only versions of MS-DOS that I have
seen that support 8" disks were SB-86 v 1.x (a rare version of MS-DOS
distributed on 8" by Lifeboat), NEC APC and 9801, and some OEM versions
of MS-DOS 1.25, 2.11 and 3.31. (those were the versions of MS-DOS that
actively supported customization)
'course you COULD use 8" DSDD from MS-DOS AND PC-DOS 3.00 on by lying to
it and calling your 8" drive a 5.25" 1.2M.

> simple chkdsk command run on the FD will tell you what you actually have.
That will identify which MS-DOS format a given disk has on it.
HIS disks will resond with "Probable Non-DOS Disk", "Sector Not Found",
"Address Mark Not Found", or "General Failure", since they are presumably
NOT MS-DOS formatted.
"Probable Non-DOS Disk" means that it is MFM with 512 bytes per sector,
but does not have valid MS-DOS structures found on it.
"Sector Not Found" means that it is MFM, but the sectors are not 512
bytes, or not numbered the way MS-DOS expects them to be ("there ain't no
sector #1!")
"Address Mark Not Found" usually means that it is NOT MFM (such as
unformatted, GCR, FM, etc.), or is MFM at a density that is not recognized.
"General Failure" means "none of the above". An error that wasn't
successfully identified. Contrary to popular belief, it was NOT
a reference to Nam.


> Prior to HD, I don't believe any of the disks were marked with type/size.
Most of the better manufacturers put that info on the label.
With unlabelled 8" diskettes, look at the index hole position.
With unlabelled 5.25" disks, the only thing that could be readily
determined was a difference in color between the media of "HD" v LD; and
if whether there was a hub reinforcer (not present on early SD and on HD
unless added by the user)

> However, HD and DD (DSHD 720Kb & DSDD 1.44Mb) are both marked on the disk
> housing on the top foreward right corner -- top foreward right as inserted
> into the drive -- right next to the spring-loaded media cover. The cover,
I have never seen an 8" diskette with a spring loaded media cover.
MANY manufacturers of 3.5" diskettes did NOT mark the disk.
(Shall we get into the "PINCH" arrow?)

> itself, may also contain the disk capacity in KB or MB, but that's also
> usually found in later model disks...

Later model 8" disks are often marked. If not, the index hole position
identifies whether it is single or double SIDED.
Being rated for single v double DENSITY was an issue of "fidelity", and
not visible unless marked.
Received on Wed Sep 17 2003 - 13:51:00 BST