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Sub-jobs, and bi-directional i/o.
- To: Leonard.Zubkoff at CMU-10A, Dave.Touretzky at CMU-10A
- Subject: Sub-jobs, and bi-directional i/o.
- From: JONL at MIT-MC (Jon L White)
- Date: Tue, 30 Dec 80 03:02:00 GMT
- Cc: (BUG LISP) at MIT-MC
- Original-date: 29 DEC 1980 2202-EST
Date: 26 December 1980 2158-EST (Friday)
From: Leonard.Zubkoff at CMU-10A (C410LZ60)
Subject: PTYs in LISP
Message-Id: <26Dec80 215856 LZ60@CMU-10A>
I have been trying to open a PTY for both input and output in order to
control a subjob from LISP on CMU-20C (TOPS-20) with no success. I
receive an invalid simultaneous access error whenever I try this. Is
there a way to control a sub job through PTYs in LISP on the 20? Thanks.
- - - -
Date: 26 December 1980 2300-EST
From: Dave Touretzky at CMU-10A
Why bother? Since you're running on the 20, wouldn't the SUBFORK package
do what you needed?
MacLisp i/o seems to be somewhat wedged in that you cannot do input and
output through the same file object (as far as I know.) This means that
you can't open a random access file for "update", i.e. read followed by
write. Perhaps the same lossage is responsible for your PTY difficulties.
True, a subforking would be much better than a PTY. However, one could use
a SFA to combind two file-arrays into one file-like object (the sfa) thru
which you could do bi-directional i/o. See the example in the file
MC:LSPSRC;YESNOP > -- the function QUERY-IO-HANDLER is the sfa function
which is set up later in the file (look for the usage of sfa-create).