gauging interest in VAX 6000-530

From: Geoff Roberts <geoffrob_at_stmarks.pp.catholic.edu.au>
Date: Mon Oct 25 22:44:44 1999

----- Original Message -----
From: Mike Cheponis <mac_at_Wireless.Com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Sent: Monday, 25 October 1999 6:54
Subject: Re: gauging interest in VAX 6000-530


> Mark Green wrote:
>
> > Mike Cheponis wrote:
> >> Looks like the 6500 was about 13 VAX-11/780 MIPS. That would make it
about
> >> 2x to 3x slower than a 486DX2/66.

Note also that it is 13 VUPS PER CPU. A 530 has 3 cpus.
Consider this, if the pci buss can't effectively serve a single cpu to the
point
it is being fully utilised, what chance does it have of coping with the
thruput load
on a multi cpu system. The Vax can and does. IIRC, the XMI gets saturated
under high workload when something like 5 or 6 cpus are fitted.

> > Integer performance is a very misleading
> > measure of performance when you are talking about system performance.
>
> My main belief is that nobody is going to keep a VAX anything running with
> dozens of simultaneous users.

Eh? ROFLMAO. Sorry, but it appears to me that you have not been exposed to
these machines, or
you would not be making this statement...

> So, if a VAX is to be something close
> to "useful" today, it'll be in single-user mode. In that case, Integer
> performance is very important.

I'll be sure and tell our Vax 6000-440 that one. It could probably use a
laugh.

It's currently:
1. Domain mail server (MX 5.1) (SMTP mail exchange for the Unix types)
2. POP3 server for about 400 users. (IUPOP3)
3. FTP server for the domain, including anon ftp etc.
4. Web server for the school site. (WASD)
5. HTTP Proxy server for 150+ PC's
6. Web based email access to VMS mail for users out of town etc. (WASD's
Yahmail add on)
7. NFS serves it's drives to various Win9x boxes for ease of updating web
sites etc..
8. I use it to snarf files from various sources, since it's FTP never gives
up.
9. It automatically mirrors parts of certain commercial sites so that
software on the pc network
    can update automagically without 150 pc's hitting the commercial site
for (for instance) virus
    dat file updates.....
10. I use it's telnet/ftp/lynx etc to do all sorts of other stuff.

Going flat out on a good day, it probably uses about half of the cpu time
available.
An individual process can push 1 cpu up to 100% or close to it, but it still
services
other requests (like POP when there are 3 rooms full of people surfing
happily) quite well.
SMP on a Vax works very well, unlike the NT attempt at it....

> Now, perhaps if we were to port Apache to the VAX, and used that I/O
bandwidth
> on multiple DS3s, well, that's great.

Too late, there is an apache port to VMS being done. I doubt if it's any
easier to use/better etc than
the WASD server we use, but I've never used Apache so I'll withold
judgement.
I just hope it's better than the Samba port. The inherently different file
systems make some
porting very difficult, since the equivalent services don't exist or are
radically different between VMS and
Unix.

> > for example, all except
> > the most recent PCs, there is only a single bus. This bus
> > must be used for all memory transfers, graphics, I/O, etc.
> > On a single user system, this is sometimes okay, but for
> > multiple users forget it.

Correct.

> Hey, I'm not saying the original IBM PC was going to outperform the VAX
6500;
> but a modern PC will crush any VAX in any application, IMHO, with
equivalent
> h/w attached.

Not so, sorry. A PCI buss pentium would die horribly under this machines
load.
Even more horribly if it was running NT. For a single user environment some
apps
would certainly run faster, but for throughput, multi-user, multi-tasking
etc,
the PC architecture is not a serious player.

> > Most of the VAXes had multiple
> > busses, and each was dedicated to a particular function.

A 6000 box (usually - I have 1 XMI only machine) has 2 busses, the XMI buss,
which is rated at 100 megabytes per second thruput (no, I don't mean
megaBITs) and is
64 bits wide, and the BI Buss, which is rated at 13 Megabytes per second and
is (I think) 32 bits wide. You should also note
this is not burst, but constant.

The CI (Computer Interconnect) Buss is not really a buss in the accepted
sense, but a dedicated 70Mbps network on what is
essentially thick (as in semi rigid - great cable for ham radio vhf/uhf use
BTW) ethernet. It's used to link/network machines in a cluster and for HSC's
(Heirarchical Storage Controllers) to serve disks and tapes to all machines
on the cluster, and is full duplex with redundant data paths. It 'lives' on
an adapter card in the vax, and can be either an XMI or BI card, depending
on the system
configuration. I have examples of both...

To use an automotive analogy, PC v VAX is roughly like this.

PC-CAR has a Super turbo charged V12 driving a single manual gearbox stuck
in first gear. The motor screams, but it
can't make the car go really fast because the mechanism for transferring the
power to the road wheels is broken/inefficient.

VAX-CAR has a normally aspirated 6 cylinder driving a couple of variable
ratio autotrans each driving separate sets of wheels,
and is capable of using the full available power of the cpu(s) to push the
car as fast as the engine(s) are capable of driving it.

This analogy is rough in places, but you get the idea.....

Hope this helps shed some light on the subject....

Cheers

Geoff Roberts
Computer Systems Manager
Saint Mark's College
Port Pirie, South Australia.
Email: geoffrob_at_stmarks.pp.catholic.edu.au
           netcafe_at_pirie.mtx.net.au
ICQ #: 1970476
Received on Mon Oct 25 1999 - 22:44:44 BST