Not possible to send two disk drive commands after each other

From: Christian Johansson (
Date: 2004-02-07 23:12:41


I just noticed that if I in assembly first send one disk drive command to
the disk drive, e.g. "U1 3 0 1 0" and I then immediately after the carriage
return send another disk drive command such as "B-P 3 0", both commands
fail. The drive light starts to flash and if I read out the error channel it
says "30 SYNTAX ERROR". If I just send one of the disk drive commands it
works well. Why is this? Must there be a pause between the commands for it
to work or do I perhaps have to call UNLSN followed by LISTN between the
commands or do something else to get it to work? (For my application I found
that the B-P command was superfluous so I could just leave it out but I
would still like to know how to do.)

Best Regards,

Christian Johansson

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