Date   : Mon, 15 Jun 1981107:31:00-MDT
From   : CSVAX.dmu@Berkeley
Subject: one of the most important but overlooked differences

The recent document comparing UNIX and CP/M is difficult
to answer objectively.  I have used both, although have
used UNIX MUCH more.  Anyway, the problem in these comparisons
don't convey the flavor of the system:
the underlying world-view of the original design that no
amount of fancy user-level sofware can completely mask.

FLAME ON:

UNIX has a `delete' key that aborts a user program
WITHOUT any special code in the user program.
CPM has this polling philosophy towards I/O (just look at
the BDOS interface) that makes it hard to poke programs in standard ways.

Berkeley UNIX has a job control facility that permits
the user to take any job (a pipeline of processes)
and suspend it, restart it in the background,
or move it into the foreground.  Thus, from any interactive
program, one can stop it, and enter commands to the command interpreter
WITHOUT any code in the interactive program.

UNIX has ``toolbox'' facilities that let one combine programs
in unexpected (by the applications programmers) ways.
Pipes, the absence of OS-supported file formats (this is a FEATURE),
redirection, tools that support applicative programming
(sort, uniq, awk especially) provide the user with a friendly,
powerfull environment that allows one to shape the software
to the human's needs, rather than vice-versa.

Finally, UNIX may not have thousands of cottage programmers
out there plugging away with applications,
but instead it has hundreds of researchers (e.g. Aho) building tools:
There are many screen editors, vi (Berkely editor), EMACS versions,
edtv, syntax-directed editors, take your choice.  There are
several PASCAL's.  There are word-processing programs that are
simply amazing (e.g. awk, an interpreter with both regular-expression
matching and procedural language).  Troff and TEX
are just two of the formatters available.  Software control tools
allow you to change any file and recompile everything that depends on it
(and no more) with just one command.

UNIX is not the be-all and end-all of Operating Systems, but it is the
only reasonable choice for a 16-bit machine.  If you can afford
it, (and memory prices are going down all the time), you should
get it.

P.S. UNIX has LISP and MACSYMA running on it.
FLAME OFF
David Ungar