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From: martin@medix.UUCP (Brian K. Martin M.D.)
Newsgroups: comp.sys.apollo
Subject: Re: Parallel pipes
Message-ID: <8706241948.AA11755@uhmanoa.ICS.HAWAII.EDU>
Date: Wed, 24-Jun-87 23:36:31 EDT
Article-I.D.: uhmanoa.8706241948.AA11755
Posted: Wed Jun 24 23:36:31 1987
Date-Received: Fri, 26-Jun-87 07:02:13 EDT
Sender: uucp@ucbvax.BERKELEY.EDU
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> In article <8706151717.AA02467@yale-eli.arpa> ram-ashwin@YALE.ARPA (Ashwin Ram) writes:
> > >  Incidentally, I think someone once complained that the Aegis shell didn't even
> > >  have parallel pipes.  I almost changed that at SR8, only to discover that a
> > >  number of people were doing things like: "catf file | srf > file"
> > >  (translation: "cat file | sort > file") and making any changes would break
> > >  them quite badly.  Sigh.
> > 
> > My feeling is that disallowing "catf file | srf > file" is no worse than
> > disallowing "srf file > file" (which many naive users also tend to do), and
> > the advantages of parallel pipes outweigh this minor disadvantage anyway
> 
> Ah, but you don't have to answer the UCR from someone who didn't read the 
> release notes and just trashed a weeks worth of work. :-)  Seriously, as I've
> mentioned before, we tend to be very conservative when it comes to breaking
> things.  In this case I didn't feel that the advantages were worth the risk.

That's one of the many reasons why I don't use the Aegis shell.  The
"catf file | srf >file" problem doesn't exist under UNIX.  For example,
the UNIX sort command "sort -u -o foo foo" replaces the file foo with
a sorted version with all duplicated lines removed.  Perhaps part of the
problem is that Apollo's software engineers didn't give adequate thought
to how a sort (e.g., srf) command should work.  Since a sort command shouldn't
generate any output until the entire input has been processed, then it
seems reasonable to allow the user to replace the input file with the
output of the sort command.

When I first started working with Apollos, I decided to try to port
some Bourne shell scripts that I use for preliminary NLP in the
analysis of medical citations and databases for KB construction to a
strictly Aegis environment.  I gave up after just a few hours.  My big
motivation was a lack of disk space--a 72MB DN3000 with Aegis, bsd4.2
and system V and various compilers leaves very little real work space.
(I bought the DN3000 before the cartridge tape drives were available
and before Apollo announced bigger disk drives, else I would have
gotten the 348MB with a cartridge tape)

I found that I was unnecessarily creating temp files, and that I was
unable to locate the proper Aegis commands with which to replace the
UNIX commands.  For example, I extensively use the sort, uniq, join,
comm, awk, sed, lex and egrep commands. But I certainly haven't found
all these capabilities under Aegis.  So I gave up, loaded UNIX, and
rewrote the shell scripts in order use as little disk space as
possible.  I also started brow beating myself for not buying a Sun,
which would have given me twice the disk space, twice the main memory
(8MB vs 4MB), a cartridge tape instead of a floppy, bundled software
and all the UNIX tools I needed for the same price as my hamstrung
Apollo.  But I digress...

Regards,

    Brian K. Martin, M.D.
    Martin Information Systems, Ltd.
    3420-A Hinahina Street
    Honolulu, Hawai'i 96816

PHONE: (808) 735-5661
ARPA: uhccux!medix!martin@nosc.mil
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