Very Computer

We asked our SE, and since he didn't know
he came out with a tech and they spent a day
taking apart the machine and removing memory
chips. After which the system would crash when
we tried to bring up the X (mwm, or any other
intensive X client). So we thought not.

Then we heard in a round about way that an
upcoming release of AIX might fix it.

Since we have not got a straight answer from
IBM, I thought I would poll the general public
to see if any of you could help.

Our sales people would really like to sell our
application utilizing 220's, since they are
so much cheaper.

Anxiously awaiting a response,

Bruce E. Parkin                         "Life is what happens to you
uunet!ncsys!bruce                       while you're making other plans."

I did a bunch of real-life testing of different machine
configurations.  Serious performance degradations appear if the
machine doesn't have fairly large amounts of RAM.  In summary:

        8Mb - Never tried it.  It wouldn't boot.
        16Mb - Small applications run fairly well.  A little slow if
               running X11.
        24Mb - Small applications run well under X11.  Medium-sized
               applications have acceptable performance.  Compilation
               and linking is quite slow.
        32Mb - Medium-sized applications run fairly well.  Compilation
               is acceptable, linking is slow.
        48Mb - Medium-large applications run well.  Compilation and
               linking speeds are usually good.
        64Mb+ - Large applications run well.  Multiple developers
                won't impair each other.

A 32Mb development system is adequate but not great.  A 48Mb
development system is good for most development projects.  Anything
over that is pretty much gravy.  I've tried systems up to 96Mb with
one to four users -- after 64Mb multiuser performance becomes pretty
acceptable under 3.1.X (it suffers pretty badly at lower memory
configurations).  I haven't tried low-memory configurations under 3.2,
but in general multiuser performance under 3.2 is far better than
3.1.X.

Swap space is harder to judge, it depends a lot on your job mix.  I
strongly recommend 100Mb for the first developer and 50Mb for each
additional for projects of about 250,000 lines.  I had a lot of
trouble on a 64Mb swap single-user system -- ld/bind and dbx kept
getting killed (and occassionally my X server).

I wrote a document on real-life memory and swap usage for CodeCenter
users (which would be on the heavy side of normal developers).  It
pretty much details what I've said here.  If anyone wants it they can

Note that the requirements and observed performance were mostly
checked under 3.1.X.  I haven't noticed a lot of improvement with 3.2
except that multiuser performance doesn't degrade nearly so fast; swap
usage is still pretty well up there for developers.

Hope all of this helps,

jim frost

We also have a 220 with 16M running all of our standard X clients without
any problem- (note, however, we were not using the X clients supplied by
IBM, but instead built our own; your milage may vary).

        -Lucien
--
----------------------------------------------------------------------------

MIT Athena Systems Development |

Quote:>Our sales people would really like to sell our
>application utilizing 220's, since they are
>so much cheaper.

 -Steve
--
 The opinions expressed above are those of the author and not SPSS, Inc.
                        -------------------

     Steve Adams                              Fax:   (312) 329-3558

I remember when IBM first announced the RS/6000 -- the minimum
configuration was 8 MB.  That didn't last long.

--

Quote:>I remember when IBM first announced the RS/6000 -- the minimum
>configuration was 8 MB.  That didn't last long.

I remember when IBM announced it, too.  I was wondering how they'd
explain to customers that their nice new machine needed a few thousand
in extra parts in order to boot.  The next thing I knew the standard
minimum configuration was 16Mb (at the same cost) which made the whole
thing a moot point.

Happy hacking,

jim frost

The CAD package ran about 4 pct FASTER at 16MB.  (no paging).
That doesn't mean, of course, that I'd recommend it for a professional
software developer's system... 32MB is good for that.

Quote:>>I remember when IBM first announced the RS/6000 -- the minimum
>>configuration was 8 MB.  That didn't last long.

>So far as I know they never shipped any 8Mb systems to real customers
>-- the last time I checked AIX wouldn't boot on an 8Mb system (I think
>I last checked at around 3.1.2 -- I'm absolutely certain that 16Mb was
>minimum on 8943 through 9021).

AIX, both 3.1.x and 3.2, WILL boot on 8MB systems, though you have to build
the kernel differently.  If you build it on an 8MB system this is done
automagically.  If you're planning to stick a system in the corner to run
a small to medium size FORTRAN program continuously, an 8MB 320 with 160MB
disk may still be one of the cheapest sources of MFLOPS around!

Other than that, though, 16MB is a reasonable minimum, at least for students.
--

IBM Champaign

:Does anyone have any experience trying to get X
:to run on a 220 (AIX 3.2) with only 16 meg of
:ram?

No problem, X run fine.
Our 220 was installed with the "remote /usr" option.
/usr is taken from a 320H running 3.2.

Are you sure to have at least 32 Mb of swap space?

Bye, Lanfranco

--
Lanfranco Albani - CAD.LAB s.p.a., v. Ronzani 7/29, Casalecchio, Italia

Phone: (work:) ++39 (51) 6130360, (home:) ++39 (51) 727372;
Fax: ++39 (51) 6130294 (work only), Fidonet: 2:332/407.1138 (home only).