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From: rde@ukc.UUCP (R.D.Eager)
Newsgroups: net.arch
Subject: Re: RE: Why Not Virtual Files?
Message-ID: <4259@ukc.UUCP>
Date: Wed, 20-Jun-84 11:41:31 EDT
Article-I.D.: ukc.4259
Posted: Wed Jun 20 11:41:31 1984
Date-Received: Thu, 14-Jun-84 00:56:15 EDT
References: <2572@ncsu.UUCP>
Organization: Computing Lab. Kent University, England
Lines: 20


    I  have  used  a  mainframe  system (not MULTICS) which uses virtual
files exclusively for about 5 years.  The answer is that getchar/putchar
are still there; they  simply  treat  the  file  as  one  large  buffer.
Normally,  the  C library (or whatever) still has a pointer, but it only
relates to the current buffer load.  Thus there is no difference as  the
old-timers see it.

    Having  got  that  out  of  the  way,  let  me  say  that for *some*
applications virtual files are pretty neat.  Trouble is, most  languages
don't  have  any facility to get at them!  We have a FORTRAN system (OK,
OK, let's assume it's all been said) which allows you to map COMMON onto
a file.  Great for large amounts of data which are updated in itty bitty
bits.  I could mention other benefits, but I think  my  main  point  was
really  that  conventional  I/O is still possible and no less efficient;
the language library actually has less to do.

      Bob Eager University of Kent UK

      (...ukc!rde)