6 Dec
2024
6 Dec
'24
12:05 a.m.
It appears that Marc Rochkind <mrochkind(a)gmail.com> said:
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I don't think files as pipes would be "transparent to the user." Reading
an
empty pipe causes a wait until the bytes requested are available, unless
the pipe is closed first. ...
You should read Meinz' paper. This was a cut down version of Unix that ran
in 40K bytes on an LSI-11 with a couple of floppy disks. It ran one program
at a time, since swapping to floppies was absurdly slow. The pseudo-pipe
ran the first program which wrote the output to a file, then ran the second
program which read it. It was close enough for most purposes so long as
the disk didn't fill up.
Still, the same sort of pseudo-pipes were in MS-DOS,
and they were
occasionally useful.
I can think of lots of places that had a way for one program to write a temporary
file that a subsequent one read. For example, in OS/360 JCL you'd write (well,
punch)
something like this for the object output of the Fortran compiler
//SYSLIN DD DSNAME=&OBJECT,DISP=(NEW,PASS),UNIT=SYSSQ
and then in the linker read it in
//SYSIN DD DSNAME=&OBJECT,DISP=(OLD,DELETE)
The & in the name said it was a temp file so make up a unique name. I probably
didn't
get the JCL exactly right since it's been about 50 years since I wrote any.
R's,
John