Performance of 80486 based machines running Unix

[Chin Fang]

In article <1587 at caslon.cs.arizona.edu>, cro at cs.arizona.edu (Charles R. Oldham) writes:
|> Hi *,
|> 
|> 	Is anyone out there running an 80486 box with either SCO Unix
|> or Interactive's 386ix?  My office is looking at purchasing either a
|> 486 based machine, a Sun, or a RS/6000 machine, and I'm really
|> interested in what kind of performance a 486/33 or 486/25 can deliver.

As someone who takes care of RISC 6000s on a daily basis, I venture to 
give you my own opinions, I post it instead of mailing because I believe
this is of general interest.  As RISC 6000 low end model is on par with 
high end 33Mhz 486s...

|> 
|> 	I need to be able to do the following:
|> 
|> 	- Run the Uni*Verse command language (lang like dBase)

I am not familar with this product.  If it's PD, I would say you can port it.
If it's commerical, check with your vendor.

|> 	- Connect to the Internet for mail and news via TCP/IP

Sure, no problem on this one.  As long as your news/mail server is NOT an IBM
I am serious about this.  Folks at IBM Austin are trying to fix this, but 
meantime, you have to watch out.

|> 	- Provide access for between 5 and 25 users, 10 of those will
|> 	  probably be dialup over 2400 baud modems

That's fine.  AIX 3.1 even comes with xmodem.  I built zmodem/kermit without
much hassle. They work too.

|> 	- Provide standard local email for above users

That sure works.

|> 	- Possibly run FoxBase or dBase

Again, these are commerical products, so please check with your vendor(s).

|> 	- Have enough power left over for me (the sysadmin) to handle
|> 	  some heavy programming chores without having to step out for
|> 	  a cup of coffee everytime I run a make.
|>

RISC 6000s, if not NFS networked, provide outstanding disk performance.
For sysadmin job, it has plenty power.  The SMIT system admin interface is
fairly easy to use too.  Better in many ways than 386 unix sysadmin stuff.
 
|> 	Speed degradation is a real concern for us, as we are
|> providing some computing resources to non-computer-users.
|> Unfortunately, these non-computer-users are also the ones who
|> partially determine our budget, so the machine will have to be quite
|> responsive. 
|>

I would say if you or your usrs need to do floating point intensive work, 
RISC 6000s, even with their rough edges, are worth to consider.  Otherwise,
GO WITH either SUN or a well designed 33Mhz 486.  AIX 3.1 is not a matured
product (at least not matured as SUN OS or SYSV stuff).  The raw power of 
this line is impressive but if you want to network them in a hiterogeneous
environment, you will experience quite a lot funny things :-(

In addition, porting many PD things to RISC 6000s often is a test of 
one's hacking ability, even though none is too difficult.  But they
do cost you time/energy.

It doesn't come with X11R4.  The "enhanced?" X11R3 from IBM sucks!
but you can build R4 libs/fonts/rgb for it without much hassle.  No
R4 server however.  

The AIX Jounal File System is robust but if you NFS your machine, you can't
enjoy it either.  This has to be taken into account.  You may want to 
read comp.unix.aix, a news group focused on RISC 6000s and to certain
extent, PS2 runing AIX.  It's from IBM Austin and many AIX developers
are active in this group.  It has been a good src of help for me.

The on line docs from IBM, in my opinion, is better in many ways than the
traditional man(1) however.  Of course, man is also available too.
 
|> 	While we're at it, can someone also fill me in on the
|> differences and advantages of either 386ix or SCO Unix?  I know they
|> both are sysV based unices, but do they provide some of the BSD
|> niceties also (i.e. job control)?
|> 
System V r4.x offers you many BSD features. check with FAQ of this group.

Finally, I cite a few numbers as reference.  They are for RISC 6000 320.  For
320 H (the upgraded version, and cheaper too), multiply them by 1.3.

29.5 MIPS,  8.5 MFLOPS, SPECmarks 24.6.

The second one is pretty realistic as my own fp jobs runs about 1.5 times faster
than what they need on a SUN SPARC 2.  33Mhz 486 is about 1/5th of such 
as far as floating point performance is concerned.  But fast hardware never
can substitute a smooth/polished/robust OS, so you may want to consider the pros
and cons in this area carefully.

Sincerely

Chin Fang
Mechanical Engineering Department
Stanford University
fangchin at leland.stanford.edu