2 Jun
2016
2 Jun
'16
5:48 p.m.
On 06/02/2016 05:09 PM, Fred Cisin wrote:
I hope that Chuck will correct some of the errors that
I made below:
I think you've pretty much got it.
No need for drivers IFF your hardware (FDC and BIOS)
and OS were new
enough. I think that SOME FDC boards that supported 2.8M data
transfer rates had BIOS chip to "update" the system BIOS.
If the 2.88M-capable FDC wasn't part of the motherboard, it generally
had a BIOS on the card for the extra stuff. This was certainly true of
the CompatiCard IV and a few other "special" FDCs (i.e., those with a
separate connector for a 2.88M drive).
NT 4 had no problem with the drives, but then, it could also support
3-mode drives (1.23M 360RPM 8x1024 format). I believe that pin 4 on the
floppy interface was used to switch speeds.
Was it 4.00 that added 2.8M?
Sounds right--but it may also be a matter of *which* 4.0. MS or IBM?
DRIVER.SYS V DRIVPARM=: DRIVER.SYS permitted using
formats that were
newer than the SETUP program knew about, such as 720K 3.5" on 5150
and 5160, or pre 3.5" 5170. DRIVER.SYS created an additional drive
letter, so the 3.5" drive would end up as drive D:
DRIVPARM changed the specs of the drive without creating a new
letter, so your 3.5" could still be B: DRIVPARM was undocumented in
PC-DOS 3.20 and 3.30, but it WAS there, and worked just fine with
generic BIOS. BUT, I was surprised to find it FAILING with real IBM
BIOS (or image thereof) in the same machine! Good reason to leave
it out of the manual!
DRIVPARM was sort-of-disabled on PC-DOS 3.2 and 3.3. You had to suffix
the "DRIVPARM" with three control-A characters (hex 01) to get it to
work. At some point, the device types for SD and DD 8" drives were
nulled out, but I don't recall when.
BTW, if you had four floppies installed, and the BIOS
understood,
then your floppies would be drives A:. B:, C:, and D:. and you hard
drive would be drive E:. But some programs were "hard-wired" to
assume C: as the hard drive, including the INSTALL for MS-DOS 5.00!
MICROS~1's answer: "Install it on drive C:, and then copy it to the
hard drive that you want it on." I refused to install it to a 3"
disk, so I installed on a different machine, and created a 360K boot
disk, plus copied all of the other files to a sub-directory on the
hard disk (E:).
At some point, MSDOS decided that the hard disk would always be C:, with
any additional removable drives trailing that. That probably helped a
lot. And there was always a drive B:, whether or not a physical drive
was present (if not, it mapped to drive A: with suitable prompting
messages).
--Chuck