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From: lshao@nation.ics.uci.edu (Ling Shao)
Newsgroups: comp.os.misc
Subject: Re: questions on coherent
Message-ID: <26E7A553.26117@ics.uci.edu>
Date: 7 Sep 90 13:49:07 GMT
References: <1990Aug30.130037.14@acad2.anc.alaska.edu>
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In <1990Aug30.130037.14@acad2.anc.alaska.edu> asgad@acad2.anc.alaska.edu writes:

>From: asgad@alaska (george dowding)
>Subject: Coherent

>I am thinking of purchasing the coherent operating system.  It claims to be an
>independently created UNIX clone.  Its supposed to be just like unix (minus
>the cost).  Furthermore it will work under minimal conditions (IBM AT w/640k)

>Has anyone tried this system?  If so, is it all that it is cracked up to be?

I have been trying out the Coherent OS for almost a month so I guess maybe I
could give you some ideas about this OS.

Mark Williams Company is correct when it claims that it is a multi-user,
multi-tasking operating system. It does provide the most rudimentary "Unix"
functions and it comes with some pretty nice utilities. In my observation,
Coherent appears to be in the class of Unix Version 7 OS. Mark Williams
has been real careful in avoiding to use theord Unix in its documentation.
In fact, I think I could not find more than 10 sentences that contain the
word "Unix". There is no explicit documentation to state its level of
compatibility with the "real" Unix.

So far, everything ses to work. However, I haven't really dug into the
C compiler and try to write out some programs so I don't know how source
compatible Coherent is. By looking at the library header files, it looks
compatible (to version 7).

If you are planning to get this system, don't expect anything fancy out
from it. After all, it is a $99 OS which is even cheaper than MS-DOS.
The OS comes with the basic Bourne Shell (no Csh or Tcsh unfortunately).
It does come with emacs, yacc, lex ... There is the basic Unix email system
but no fancy stuff like mh_mail. About the performance, I wouldn't say it
is exceptionally fast (I am running it on a 10MHz AT Compatible) but the
speed is certainly reasonable. The time when the system really slows down
is when there are more than 2 tasks accessing the harddisk at the same time.
If your foreground task is also accessing the hard disk, you might have
to wait for a while (~5 - 10 secs, depends on what you are doing). However,
the effect on a foreground task running completely in memory is minimal.
I think this is more of a problem for the ISA architecture rather than the
OS as ISA is not really designed for multi-user multi-tasking operation.

So, what do I really think? (i.e. Am I going to return it before the 60 days
trial period is over?) Well, it is kind of hard to say right now. First, I
brought this system just for hobby at home. This system is not good enough
to serve as a real production system (if you want the real stuff, get a Suns).
For hobby, I think it is perfect. However, I am also considering Minix right
now.

Minix does have some advantages over Coherent. First, Minix has been around
for longer and I presume it has a much larger installed base (the
comp.os.minix newsgroup has 26000 readers). Unlike Coherent, it does
support networking on ethernet (TCP/IP is not officially supported) and
it works on the Micro Channel based PS/2 after being patched. It is
constantly being maintained and upgraded by thousands of people across the
nation. Also, Minix runs on machines ranging from PCs to 386 to Atari ST.
In the coming years, it will also run on Mac and Amiga. The developer is
also making it to be more Posix compliant.

However, Minix does have at least one major limitation. Many utilities
(which I personally think are very important) are not provided in the
official release of Minix. Minix v.1.3 doesn't come with emacs, mail,
lex, yacc, and uucp. You might be able to get these stuff from independent
developers (since there are so many people working on Minix) but I don't
know how easy or reliable that is going to be. Minix V.1.5 should be
coming out by now or pretty soon and I certainly hope they will at least
provide emacs and uucp in the official release. The missing of some of
these utilities is a major problem for me. Even though I am using
Coherent for hobby, I do need at least an emacs editor so that I can
write programs (I can never use mode oriented editors like vi). I don't
mind having to write my own Csh but at least give me a good editor to use.

Chung Ng
Information and Computer Science Department
University of California, Irvine
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 Ling Shao (Shao)               |   INTERNET address: lshao@ics.uci.edu
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