> But I do want to hear from those who prefer MPE over Unix
> and have used (or administered) both enough to compare
> them.
FWIW, I much prefer MPE over Unix, even though I learned Unix first
(maybe it was because I learned MCP before Unix - I still miss CANDE's
built in editor from time to time).
 
Experience:
15 years Unix user, 10 year admin. 12 years MPE user, 7 or 8 (I forget)
years MPE admin (overlapping years all around). (Meanwhile also
programming, Netware, powerhouse, tcp/ip, etc. - never any one thing
full time, but many things at the same time.)
 
>
> Please be specific.  Some of these deficiencies in Unix
> may represent business opportunities!
>
> Some things I have heard about UNIX:
 
>    (1) Crashes more often.
ATT System V.0 - not stable (but wasn't supposed to be and wasn't
commercial at that time).
ATT System V.3 and V.4 - stable.
HPUX 9.x (limited 10.x experience, so far) - very stable. Doesn't
  crash for silly reasons like running out of room in the root
  file system.
 
File systems can have problems, still. We just crashed one of our
new 10.x file systems by a simple command and by ignoring the
warning (at least there *was* a warning). We had ignored it before
without any problem... Then there was the example of the failing
disk that wasn't reported as a problem, unless you look at the
current status of the mirroring we had running. This problem
could have existed a long time without being noticed. I'm pretty
sure MPE would be much more forthcoming if a mirrored disk failed.
 
>    (2) Uses more resources -  memory and CPU.
Depends on needs, but for things like databases MPE is great
and very economical (largely due to Image and the MPE file system,
IMHO). If you stay within the MPE design framework (see other posts),
memory and CPU usage are very economical and you can't get this economy
from Unix, except at an high cost in file and data integrity. Look
at HP's recommendations for sizing memory for similar sized CPU system
between MPE and HPUX - in the configuration guides.
 
>    (3) File system takes longer to recover after crash.
Yes. Haven't tried JFS yet - afraid to, since it is new, it isn't the default
file system, it doesn't support ACLs, and we're going to need all the disk
performance we can get. I never even think about MPE recovery, in the first
place MPE doesn't crash (hardly), and in the second, recovery of the file
system to so transparent that you don't notice. With Unix, you must always
think about the file system and you can't always fix it with fsck, either.
HPUX is better that ATT Unix, but nothing like MPE.
 
>    (4) No good print-spooling.
Certainly MPE has more goodies. Depends on your needs for what "good"
means.
 
>    (5) No built-in support for KSAM, CIR, or database (IMAGE).
>        Does this really matter?
A central point, IMHO. - Don't leave out the message file, which is
a great MPE feature (like shared code).
 
I'd add (6) general oddities and troubles. You can find strange behavior
in both MPE (especially with Posix) and Unix, but you can depend on
running into it with Unix, whereas with MPE, you can generally depend
on it not happening. (E.g., I have a workstation that in single
user mode doesn't perform carriage returns, for no reason anybody
has been able to figure out.)
 
Also, (7) the flexibility of Unix gives you a far greater range of choices
in how to implement almost anything. This can be a blessing, but more often
it just results in difficulting understanding the benefits and costs of
each alternatives - thereby wasting time in optimizing or else, just
plowing ahead without understanding, using defaults, then running into
unexpected roadblocks.
 
With MPE, the defaults generally work for you - your better off knowing how
to control things (like spreading datasets across multiple drives), but the
defaults work well for the usual business, transaction-oriented application.
But with Unix, the defaults are either the first way something was programmed,
or the way the programmer thought would be easiest (for them, not you) - often
not what you want at all. (Example, what is the default umask? Compared this
with the default security MPE assigns.)
 
These things combine to make Unix much more expensive to (8) administer well,
since there are a great many more things to know. Now, there is a benefit
side to this in that Unix gives you a wide range of more "stuff" (like
awk, curses, and stty), but use of these features comes at a cost and they
tend to be more helpful to programmers than to application users.
 
(9) MPE also has real batch processing and Unix just has multiple on-line
sessions (and cron jobs - if you have figure out the syntax and what to do
with the input and output and error output)
 
(10) MPE has priority queues, with options for how CPU is allocated [decay vs
oscilation], whereas Unix just has the "nice" command and stupid [every
process is equal] CPU allocation (unless you have add-on tools).
 
Richard
--
-- - - - Speaking for myself and not necessarily anybody else - - - - - -
Richard Gambrell        | Internet: [log in to unmask]
Mgr. Tech. Services     | POT:      504-483-7454     FAX: 504-482-1561
Xavier University of LA | Smail:    7325 Palmetto, New Orleans, LA 70125