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Path: utzoo!utgpu!water!watmath!clyde!rutgers!ames!oliveb!pyramid!prls!philabs!tg!dasys1!cforeman
From: cforeman@dasys1.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: Strange DOS behavior
Message-ID: <377@dasys1.UUCP>
Date: Sun, 10-May-87 19:27:54 EDT
Article-I.D.: dasys1.377
Posted: Sun May 10 19:27:54 1987
Date-Received: Thu, 14-May-87 04:56:10 EDT
References: <1293@ur-tut.UUCP>
Organization: Datamerica Systems, NYC
Lines: 28
Keywords: DOS
Summary: MS-DOS pipes aren't really.

In article <1293@ur-tut.UUCP>, akk2@ur-tut.UUCP (Atul Kacker) writes:
> 
> A>  TYPE filename.ext | MORE
> and I got an error message  
> Write protect error writing drive A:
> I am only trying to read from the disk. Am I missing something here ?
> -----------------------
> Atul Kacker
> UUCP: ...seismo!rochester!ur-tut!akk2

What you are missing is the way MS/PC-DOS handles pipes. When you pipe
the output of TYPE into MORE what actually happens is that temporary
files are created by the operating system which contain the output from
TYPE. When the TYPE  command has completed, the temporary files are
used to feed MORE which produces your output. This is necessary because
MS/PC-DOS has no multitasking capability. If it did, MORE could run
concurrently with TYPE and the output could be fed directly to MORE without
ever writing to the disk. Unfortunately, this feature does not exist
and the output has to be kept somewhere - on the disk.

-Charles


-- 
Charles Foreman                  {allegra,philabs,cmcl2}!phri\
Datamerica Systems               {bellcore,harpo,cmcl2}!cucard!dasys1!cforeman
New York, NY, USA                                {philabs}!tg/
		'87 Mets - Let's Do It Again!