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From: ed@mtxinu.UUCP
Newsgroups: net.unix
Subject: Re: Re: marketing unix
Message-ID: <144@mtxinu.UUCP>
Date: Thu, 26-Jul-84 00:04:55 EDT
Article-I.D.: mtxinu.144
Posted: Thu Jul 26 00:04:55 1984
Date-Received: Thu, 19-Jul-84 02:28:47 EDT
References: <1475@pegasus.UUCP>
Organization: mt Xinu, Berkeley
Lines: 25

> ALL AT&T BTL Unix's are upward compatible.

?????  How does one move a PWB (Unix 1.0) SCCS file to System V (5.0)?
The internal file formats changed somewhere along the way,
between 1.2 and 2.0, I think.  What about object modules? Are
they compatible across versions (even staying within the same
hardware)?

If you're going to make generalizations like this when comparing
two systems, be sure they're right.  Also, be sure that your
down-side statements ("BUT how upward compatible is 4.1 to 4.2??")
have some merit.  Actually, there is quite a bit of compatability.
Most 4.1 sources will compile and run correctly on 4.2; virtually
ALL binaries (with two documented exceptions - reading directories
and the "jobs" library) can be run with "compatability mode"
compiled into the kernel.

Let's have serious technical comparisons of systems here, not
religious or marketing hype.  There are features from both systems
(4.2 and SysV) that have merit, and features from both that
are disasters.

-- 
Ed Gould
{ucbvax,decvax}!mtxinu!ed