Qume Qumetrack 542 track seeking issue
cisin at xenosoft.com
Tue Nov 5 00:23:08 CST 2019
On Tue, 5 Nov 2019, rescue via cctalk wrote:
> However, when I do a format a:, the drive will format through the 40 tracks,
> then instead of the heads returning to track 0 quickly, they do these small
> stepping 'bursts' and DOS times out saying failure..... it probably would
> have worked if DOS would wait 10 seconds or more for the drive to move to
> track 0.
Which version of DOS are you using?
Slight variation, . . .
IBM used Qumetrak 142 (half-height 5.25") on the PCJr and "Portable PC"
(similar to Compaq) It is a SLOW stepping drive.
One of the differences between PC-DOS 2.00 and 2.10 (released at that
time) is that 2.10 has a much longer stepping time. The previous
stepping time by default in PC-DOS 2.00 was not long enough for the
Qumetrak 142 to step. Getting the step pulses too quickly caused it to
miss some of them.
Consider building a different table in memory, and repointing Int1Eh at
the new table.
BTW, MS-DOS 2.11 is one of the versions of MS-DOS that has a lot of OEM
customization. For example, IBM didn't support 720K until PC-DOS 3.20,
but there were a number of MS-DOS machines that started using 720K at
2.11 Gavilan's 3.5" format didn't match the one that IBM went with
until Gavilan MS-DOS 2.llK
(The other MS-DOS version with a lot of customization is 3.31. For
example, support of drives larger than 32MB)
More information about the cctech