Qume Qumetrack 542 track seeking issue

Fred Cisin 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)

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