Important Info for Obsolete Hardware

[baltoro]

What Is That Horrible Grinding Noise Coming From My Floppy Disk Drive?

[vanjast]

Just a jump to the left.... 'LET'S DO THE TIME WARP AGAINNNNNN'
:bg

[hutch--]

One of the great joys of modern computing is NO FLOPPY DISK DRIVES ! I have a plugin if I need one but have never had to use it.

[dedndave]

 :P
i still have about 500 5-1/4 inch floppies with stuff on them
i also have about 1000 3-1/2 floppies, but i got everything off those back in the win98 days   :P

[mineiro]

Good old days, windows 3.11 instalation stored in 13 floppies.
I remember of 2mf formatter to get a 1.88 or 1.96 formated size, played much with a nec controler. In this time I have learned about FAT.
Remembered too about opening a 3-1/2 floppies single face, flipped it to use another side. Stego hohoho.

[dedndave]

yah - i once wrote a formatter and device driver for 360 K floppies
the total formatted space was 400 K   :bg
as i recall, i used 10 sectors per track instead of 9

[mineiro]

Very nice Sr dedndave, I don't have played much with 5-1/4 floppies, in this time I was starting my adventure with pc computers, after zilog times (k7 tapes).
I have learned so much in Era of floppies, spend so much time copying simple text files to a floopy, after, deleting that file and with one disk editor tryed to recover it. Some "magic" about computers disapeared in this time. What we see today is just vestige of old times. Bytes and structures.

[dedndave]

it wasn't very practical, really
if you were to have a bunch of 400 K formatted floppies lying around, they might be mistaken as unformatted
also, IBM used 360 Kb for reliabilty reasons
they wanted to insure that the inter-sector gap was long enough to lock up on
probably not an issue for anything newer than the old shugart/mpi/tandon full-height drives

i just wrote enough code to see if it could be done - nothing fancy
no "are you sure" questions or anything   :bg
it did work fine, though - tested a few floppies with no errors

[FORTRANS]

yah - i once wrote a formatter and device driver for 360 K floppies
the total formatted space was 400 K   :bg
as i recall, i used 10 sectors per track instead of 9

Hi,

   Did you ever try larger sectors?  That was supposed to get
you more space with fewer intersector gaps.

   Probably ought to start going over my collection and transfer
their contents to something more modern.

Regards,

Steve

[dedndave]

larger sectors creates a larger problem   :P
BIOS does not support sectors larger than 512 bytes
at least, it did not on the machine i was running at the time
it may be different with newer machines
anyways, that would mean you'd have to add that functionality to INT 13h

i haven't really poked around BIOS on newer machines, much
the OS makes it difficult to look at BIOS code, and it isolates you from the INT function dispatch

[FORTRANS]

Hi Dave,

   BIOS Int 13H Fn 05H supports different sector sizes.  And
the Zenith Z-100 OEM MS-DOS could read 128 byte sectors on
8" diskettes and 1k sectors on my hard drive.  So, maybe an
experiment this weekend and see how the BIOS returns an error
message.  I do remember that my later PC compatible Zenith
386 could read diskettes that other brands could not.  Never tried
anything like that on any of the existing computers I have.  Might
just have been a foible.

Regards,

Steve N.

[dedndave]

hiyas Steve
yes - it supports different sizes - 128, 256, 512
i even wrote an old DOS ram-drive device driver
you could create 32 and 64 byte sectors in ram   :P
sectors smaller than 32 bytes didn't work because a FAT directory entry is 32 bytes (the parm is entries per sector i think)
however, if you go larger than 512, you will run into all sorts of problems
the assumption at the time was that no larger sectors would be made
all the DOS buffers are 512 bytes max - this applies to win95, and probably win98