HP 9825a

[cruff]

(04-05-2017 07:34 AM)Geoff Quickfall Wrote:  Cartridge out message when empty, but no matter what I do, error 43.

I spent about a month working on the disassembly of the 9825T firmware, which is very similar to the 9825A firmware in its patent listings.

For the tape drive error 43, this is caused by bits 3 (power off), 1 (servo failed), or 0 (unexpected BOT/EOT) of the tape controller's status register (R5) being set. These will be placed into bits 15, 13 or 12 of the ‘errwd’ (RAM base page word) by the ‘stsaf’ routine of the tape driver firmware.

At power up, the this will be caused by the probe of the tape drive during the implicit ‘ldp 0’ executed by the Extended I/O ROM at initialization time, and in addition by any explicit tape commands you may issue.

The first version of my disassember, documentation about what I have found and the disassembler output for the mainframe ROMs and most of the extension ROMs can be found at the
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