Re: Auto Boot - and the & command.

From: Julian Perry <>
Date: Sat, 6 Apr 2013 10:09:16 +1100
Message-ID: <>
Recently I worked on a patch to JiffyDOS to autoboot if the shift key
was on at power up, the idea being that one could use shift-lock to
leave the machine in a state where it would always autoboot unattended, but only
on demand.
I haven't completed it (managed to handle it through warmstart), but
was able to get it to work as proof of concept. Time, and lack of
spare bytes in the JiffyDOS ROM have so far precluded me from
finishing it.
A plug for the Easyflash3 thought - it's an awesome product for kernal
hacking/development :)
>Hm, doesn't the VIC-1540 have some rarely used feature with a USR file named
>"&" that would automatically boot when turning on the VIC-20?

That's still in the 1541 ROMS, as late as 901229-03 which executed this code if ATN (I
think) was low when the drive booted - my first 1541 (long gone)(short
board) actually had it.

Somewhere between -03 and -05 this autoexec code was removed, but the
"&" DOS command remains. I suspect the autoexec code was used as a
development tool, facilitating a direct bootstrap from disk.
Presumably it was removed because it often caused the drive to load
the error channel with error 50 (Record not found) on power up - and the drive
error LED would flash.


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Received on 2013-04-06 00:00:06

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