On Mon, 17 Jan 2005, Eric Smith wrote:
> You don't really need a 3.5" 720K drive. Unlike the 360K/1.2M situation
> with 5.25-inch drives, the 1440K 3.5" drives can reliably read and write
> 720K diskettes.
The 1.4M does, indeed seem to reliably handle 720K.
The somewhat rare 67.5tpi 3.5" drive (Epson) might have the expected
issues of track width.
> IIRC, there was a driver supplied in some (but not all) versions of DOS
> called DRIVER.SYS which had to be installed using a "DEVICE=" command
> in CONFIG.SYS in order to support extra floppies. I don't recall whether
> it allowed specifying a base IO address for a secondary controller.
> They may have removed some functionality in later DOS releases.
DRIVER.SYS was included starting with PC-DOS and MS-DOS 3.20
(when IBM started supporting 720K 3.5")
A few OEM MS-DOS versions had similar drivers since 2.11
DRIVPARM was also included, but undocumented in PC-DOS, and not compatible
with the real IBM BIOS.
DRIVER.SYS does NOT include IO addresses, etc. It assumes that there is
already full BIOS support in INT 13h
--
Grumpy Ol' Fred cisin_at_xenosoft.com
Received on Mon Jan 17 2005 - 19:19:38 GMT