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From: tli@uscvax.UUCP (Tony Li)
Newsgroups: net.arch
Subject: Re: OS info request
Message-ID: <1399@uscvax.UUCP>
Date: Fri, 11-Jan-85 02:43:41 EST
Article-I.D.: uscvax.1399
Posted: Fri Jan 11 02:43:41 1985
Date-Received: Mon, 14-Jan-85 03:29:16 EST
References: <105@endot.UUCP>
Organization: CS&CE Depts, U.S.C., Los Angeles, CA
Lines: 51

> Subject: OS info request
> Newsgroups: net.architecture
> 
> I am preparing a paper on the wonders of the UNIX operating system, and
> one of (in my opinion) its strongest points is its very small, clean
> system call interface. I would like to contrast this to some huge and
> ugly interfaces, but I am not familiar with other OS's. I would therefore
> appreciate it if anyone out there who knows VMS or some other large scale
> OS could let me know how many system calls the OS supports, and about how
> large the source code for the OS is (give or take a few thousand lines).
> Please mail me personally so as not to clutter the net, and if I get enough
> queries I will post any results. Thank you.
> 
> 					David Labuda

Hi Dave,

I don't consider this a fair contest.  How many system calls is just not 
a good metric of a OS's worth.  Let me give you some guesstimates:

	OS		# of system calls
    ------------	-----------------
       CP/M 2.2		    40
       Unix 		    100
       Tops-20		    100
       CCP/M		    150
       VMS		    250

My point is this:  OS's have different capabilities.  And capabilities take 
system calls to implement.  Would you argue that CP/M 2.2 is better than
Unix because it has fewer system calls than Unix?  I hope not.  (PS.  If so,
have I got an OS for you.  It's the best OS of all.  You can't call it! ;-)

Does the number of system calls indicate anything?  I'd say that Tops-20 is
definitely a more capable and complex system than VMS, and I think that even
you would have to agree that VMS provides more facilities than Unix.  So
the number of system calls doesn't seem to indicate much of anything.

If you're going to expound the virtues of Unix, concentrate on: ease of 
modification, large number of available tools, excellent software development
environment, and portability.

Stay away from: Efficiency, security, and user-friendliness.

Cheers, 
Tony ;-)
-- 
Tony Li ;-)		Usc Computer Science
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