🚀 go-pugleaf

In article <8604230049.AA04104@ucbvax.berkeley.edu> rgenter@BBN-LABS-B.ARPA (Rick Genter) writes:
>     Is there some way, from Basic, to determine from which disk drive the 
>currently executing program was started?  Obviously if the program was just
>typed in this should return a <No such drive> indication.  But if I typed:
>
>	RUN "D3:FOO.BAS
>
>is there something that FOO.BAS can do to determine that it was executed from
>D3: as opposed to D<anything else>:?  As this is Basic, no hack, no matter
>how gross or disgusting, will be frowned upon, as long as it works :-).

BASIC uses IOCB #7 to do all its internal I/O (LOAD, RUN, SAVE, LPRINT, etc.).
Therefore, if you do a PEEK(195) which is the ICDNO of IOCB #7 you will get
an integer which is the unit number of the device last accessed (although the
IOCB is closed by then). Make sure you do no other channel 7 I/O before you
do the PEEK(195).

If you do a PEEK(195) after an LPRINT, you get a 1, which is the unit number
of "P1:". If you do a PEEK(195) right after you did a LOAD "D6:FOO", you
will get a 6. Try it - it really works!

Bruce D. Nelson
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