Re: Not possible to send two disk drive commands after each other

From: Christian Johansson (
Date: 2004-02-08 13:42:51

----- Original Message ----- 
From: "William Levak" <>
To: <>
Sent: Sunday, February 08, 2004 1:30 AM
Subject: Re: Not possible to send two disk drive commands after each other

> On Sat, 7 Feb 2004, Christian Johansson wrote:
> > Hi!
> >
> > I just noticed that if I in assembly first send one disk drive command
> > the disk drive, e.g. "U1 3 0 1 0" and I then immediately after the
> > 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
> > 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
> > that the B-P command was superfluous so I could just leave it out but I
> > would still like to know how to do.)
> I have noticed that even in BASIC, some commands require that you read the
> error channel afterword, or the next command is not executed correctly.  I
> don't remember which ones, at the moment.

In BASIC, I can send the two commands directly after each other without
reading the error channel without any problems.


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