I hate to play devils advocate here because I absolutely love the HP3000 but
wanted to add a few comments. Please do not take these as any form of
attack. Like John, I also work with both HPUX and MPE. A vast majority of
our users are on MPE. If given a preference, I think I'd rather keep MPE
and ditch unix, however the real world just doesn't allow that. It's really
a shame.
John Wolff writes:
<snip>
HP-UX has only simple character based files (like a PC) without
structure
that cannot be locked. Every application has to manage the nature
of its
files as the operating system provides little help. Devices are
referenced
crudely by file address and are clumsy to manage.
I'm not sure what you mean by file address. I know that I simply
create device files that match the what I'm using. /dev/cdrom,
/dev/dlt7000, /dev/whatever. Easier than remembering that my first DLT7000
is LDEV 25 and my second LDEV 26. However, HPUX tends to always think that
a device is there. There is no concept of mounting tape devices like on
MPE. Sometimes this is a good thing :) As for locking, this is sometimes a
good thing too. If a user is running an application, the executable can be
moved and a new on put in its place. The first user will continue to use
their copy (in memory) while any new user will get the new executable.
Instant upgrade (or whatever you want to call it). Of course YMMV. If you
do something stupid, unix will let you do it.
<snip>
3) MPE is far and away a much more reliable operating system that
rarely
crashes or needs to be rebooted. We only boot ours when we are
patching or
updating the operating system. HP-UX should be re-booted at least
once a
month to prevent crashes.
I'd argue this point. While in general the OS is more stable in MPE
due to the extraordinary steps HP put into it while they were developing it,
it is more a function of applications. Any application that fails to keep
its own work space (memory, etc) clean tends to cause system problems. The
OS itself is very stable IMHO. I have a system here that shows an uptime of
141 days. Nothing special about that. It's a dedicated system to a
dedicated task. In otherwords, the application behaves itself. I'm not
saying that MPE is any different, I'm just standing up a bit for HPUX.
4) MPE has a much more flexible security system than UNIX. Files,
accounts
and users all can be given capabilities and/or access restrictions
to
suit. UNIX has a crude security simply based on ownership, group
membership or just being anybody.
Crude? Not sure I'd use that word. Simpler perhaps. You either
have access to a particular file or you don't. That access can be read,
write, or execute.
<snip>
HP-UX is usually limited to one instance of a given language per
computer.
COBOL and C+ seem to be the popular choices on HP-UX, but there are
others. We do not write programs for HP-UX (too difficult), but
just run
canned applications. I have written many lengthy scripts which is
tedious. The tools are basically low level, some are quite
powerful.
Why are you limited? Why can't you have different versions on the
same system. You can very easily. It's simply a matter of pointing to the
correct location.
<snip>
HP-UX has a crude, cryptic set of commands which are clumsy to use
and
requires much care to learn. Some commands are built-in to the
shell.
HP-UX comes with a choice of several shells. Most commands are
little
programs that have been added over 33 years from various sources.
Commands
usually have many tedious and cryptic options to choose from. Some
of the
commands are very powerful (even dangerous) and make for interesting
computer science in university settings.
Again the word crude. I tend to think of people who write
commands/etc for unix as being efficient. Switches specified on the command
line can really influence the way the command works. It's simply a matter
of understanding what it's going to do. Of course, this requires
documentation that is actually understandable, but that's an entirely
different story.
MPE limits you to CI JCL or JCL from another vendor, such as
VESOFT's MPEX. With HPUX, you have your choice of several CI (shells in
unix). Each tend to be better at different things. If you don't like what
you get, simply install a different one.
<snip>
With HP-UX the concept of "jobs" is another mind game. If you
launch a
process that runs in the backround you only get to see if it is
still
running in your session while you are logged on. Once you log off
it is
just another process that is difficult to monitor.
Why more difficult to monitor? You mean ps vs ps -ef | grep myname?
Or scripts that are written that don't produce any type of logging? That
would be more design than the Oss fault.
10) MPE gives us the major benefit of compatibility from one release
of the
OS to the next, each release upgrading capability without trashing
applications and jobs which have already been developed. Upgrading
of
applications can be independent from the OS and from each other!
Thus,
multiple applications can be run on a single computer! This concept
is
what makes MPE unique in today's operating system world of
UNIX/Windows.
It is the most valuable business reason to prefer MPE over HP-UX.
HP-UX is a proprietary flavor of UNIX (as is SUN Solaris and IBM
AIX) which
does not value compatibility at all. Each major (sometimes minor)
release
of the operating system will usually reorganize system file
structures
making scripts and applications unuseable until the applications are
simultaneously upgraded along with supporting tools such as
databases. All
programs have to be recompiled (at the minimum) with new compilers
to work
with a new release. Thus, it is poor planning to run more than one
application per computer because too much down time is involved and
the
coordination of various products is a nightmare. Furthermore, a
UNIX shop
should also have an extra development system on hand to work out the
upgrade process while a production system continues to function
(twice the
cost).
"All programs have to be recompiled with new compilers to work with
a new release?" I don't know where this came from, but we don't recompile
following an OS upgrade except to take advantage of new features provided by
a new release of the language. We don't upgrade our database at the same
time as the OS either.
"Each major release of the OS will usually reorganize system file
structures?" To my (albiet limited) knowledge this happed from HPUX 9 to
HPUX 10 to conform to general standards.
<snip>
12)MPE protects itself from damage, even from the system manager in
many
cases. Obviously, the system manager can wreck the system if he
wants to
but more effort is required. In HP-UX the root user is able to do
anything
to the system, even by accident, with no questions asked.
I don't really know how to respond to this one except to say if that
if someone does something stupid regardless if its MPE or HPUX, its a
problem. It's pretty simple to mess up MPE as well.\
13) Transition to an upgraded HP3000 or replacement of the system
disc is a
relatively simple matter of reloading the system and data from tape.
This
is a nearly automatic process and has been taken for granted by
HP3000
users ever since MPE was first developed. It seems only logical
that a
system should be able to boot itself from tape as well as disc, but
this is
a foreign concept to most UNIX and Windows users. This is probably
a
fundamental shock to many HP3000 users that have not ventured to the
UNIX
world.
Simply reloading? Sure, after you use sysgen to assign LDEVs to
your disk drives, after you use VOLUTIL to make these disk drives belong to
volume sets. After you use NMMGR to reconfigure your network interfaces.
HP-UX does not work that way. HP-UX requires a fresh, plain vanilla
load
of the OS which then must be configured so that it can even find the
tape
to load data from. However, just loading a previously configured OS
over
the virgin OS from tape will likely cause a crash because of
configuration
differences of devices, etc.. HP has attempted to address this
problem
with a product called Ignite. A specially prepared and current
Ignite tape
MUST be on hand at the time of disaster. However, it requires much
interaction and use by an expert to restore a system from tape.
HPUX supports booting from a tape drive or a CDROM. Tape must be
bootable, same as MPE's SLT tape. I recently had to compile documentation
on how to recovery our systems from a disaster. The general premise was
that someone with no or little knowledge of the system should be able to
perform the recovery (in practice). I found that it took fewer pages to
explain HPUX than to explain MPE, especially SYSGEN.
14) MPE comes with robust backup and recovery tools that users can
easily
master. HP-UX comes with crude tools like fbackup, tar, etc. that
the user
must cobble together with some sort of script as the first task to
do upon
owning and managing a UNIX system. Feedback from these tools is
tricky to
determine success of a backup process.
I don't see how checking return codes is tricky. That's essentially
what you do with JCWs or HP supplied variables in MPE. HPUX comes with a
menu system (SAM) which essentially lets you say, use this drive, back up
these files, and go. It will even schedule unattended backups for you.
One additional difference that really comes to mind is the lack of
applications that are on MPE. Some things have been ported, yet MPE lags
way behind.
* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
|
