Bugs/features of AMSDOS
=======================

These pertain to AMSDOS v0.50.

1) Disabling the disc error messages (using |^A) doesn't.
Reason: Maybe it's a documentation mistake.  Interaction with the
user can be disabled, but some error messages will still appear.
Solution: Patch TXT OUTPUT across the AMSDOS call!

2) If user interaction is disabled, CAS OUT CLOSE (DISC) doesn't,
for a write-protected disc.
Reason: Disabling user interaction would appear to behave as
if I(gnore) is always pressed, rather than C(ancel).
Solution: Call CAS OUT ABANDON (DISC) to force close.

3) A missing disc is reported as error code &10 ("bad command")
rather than with &48 (FDC error: drive not ready).  This is
the same error code as for bad filenames.
Reason: Not known.
Solution: Use |^H, if you know the drive number.
You can hackily get the drive number from (&a700).  Or is it (&a702)?

4) Both Soft 968 and the CPC6128 User Instructions claim the
error code for "disc changed" is 21.  It isn't.
Reason: Documentation/code error (are there any others?).
Solution: Look out for 9, not 21!

[
 10 'Demonstrate 'disc changed' error code bug
 20 ON ERROR GOTO 666
 30 OPENOUT "dummy"
 40 PRINT#9,"Rhubarb"
 50 PRINT "Insert another disc..."
 60 CALL &BB06
 70 CLOSEOUT
 80 END
666 IF ERR<>32 THEN PRINT "Unexpected error!":END
667 PRINT "AMSDOS error code:";DERR
668 PRINT "Documented error code for 'disc changed': 21"
669 END
]


Mark RISON, mrison@hotmail.com , 1999-05-31