Path: utzoo!utgpu!watserv1!watmath!att!rutgers!apple!netcom!ergo
From: ergo@netcom.UUCP (Isaac Rabinovitch)
Newsgroups: comp.lang.icon
Subject: Re: Icon pipes in MSDOS
Message-ID: <13829@netcom.UUCP>
Date: 26 Sep 90 04:44:59 GMT
References: <0093D32B5856BB80.204002AD@mis.mcw.edu>
Reply-To: ergo@netcom.uucp
Distribution: inet
Organization: UESPA
Lines: 33

In <0093D32B5856BB80.204002AD@mis.mcw.edu> tenaglia@mis.mcw.edu ("Chris Tenaglia - 257-8765") writes:


>MSDOS does have pipes, but they're implemented differently than unix. MSDOS
>does it by generating scratch files. One can actually do a DIR|SORT or
>DIR | ICONX PROG. Inside icon one can issue system("dir >_dir.tmp") and
>then infile:=open("_dir.tmp") for subsequent processing. It also uses a
>little more memory when using the system command.

Those are *not* pipes.  They are *called* pipes, but what they really
are is a shorthand for specifying temporary files.  If they were
pipes, they would allow the two programs to execute concurrently, and
there would be no question of the "pipe" filling up the rest of the
disk volume.  As it is, each program in the pipeline has to finish
executing before the next can even start.  This makes for a lot of
inefficiency.

MS made it *look* like Unix commands like "find ... | grep ... | zoo ..."
also work under MS-DOS.  But for all practical purposes, they do not.

-- 

ergo@netcom.uucp			Isaac Rabinovitch
{apple,amdahl,claris}!netcom!ergo	Silicon Valley, CA

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