From: george@wixer.cactus.org (George Wenzel)
Subject: Re: Various Responses
Organization: Real/Time Communications
Distribution: austin
Date: Tue, 12 Jan 93 14:11:39 GMT

In article <86457@ut-emx.uucp> petrilli@nextover.pe.utexas.edu writes:
>In article <1993Jan10.173053.29359@wixer.cactus.org> george@wixer.cactus.org  
>(George Wenzel) writes:
>> I have been running a public access UNIX host for some time.  It takes a
>> lot of work, a lot of people helping run the thing, and a LOT of money.
>> I charge $10 a month for access ($5 a month for EFF members and students)
>> or $50 a year for those wanting to save money.  To some it sounds like a
>> lot of money, to many *any* money is too much.  Well, the bottom line for
>> me is paying the phone bill, which *I* still pay the majority of... along
>> with the rent for the office housing the system.
>
>BBSs in general are this way, Unix machines are no better/no worse.

Yes, but how many free bbs's have a full internet feed, 12 phone lines,
etc...

>
>> I am already running a system as you describe here.  No we arn't on the
>> internet yet... but thats coming soon.  It's going to be limited, but the
>> limits are part of the real world.
>
>Well, I suspect a matter of scale is different.  As I recall Wixer is a  
>386/486 machine, whereas we're discussing an network of RISC machines  
>including a terminal server and router.  

I suspect you may not get much use out of an expensive mix of hardware if
the limited resource in such case is i/o.  We have a number of
professionals on staff, and none of them feel that RISC is the way to go.
It's like putting a rocket on rollerskates.  Wixer has an average cpu load
below .1%, and fully loaded it only goes above 1% when a large job is
running or someone is doing a compile.  We have a terminal server, and the
router is to be finished later this month.

I have been evaluating multi-processor systems, in combination with i/o
enhancements for future expansion.  After talking to people putting in
large systems in other cities, I find that on a single ESIA 486 system, you
can support 64 users at once, with i/o being the only bottleneck.  Of
course this would be pushing it...  but who said you can't have a network
of 486's, or a minicomputer based on 486's.

Wixer is on a network as it is... the only reason that we are keeping the
users on one host is bacause load demands don't indicate that the system
would show any increased preformance.  We have a fairly large drive array
on wixer (well, large enough...) and it's about half full.  

The bottom line is scale isn't an issue.  Systems such as this are scalable
by nature.  A RISC platform does massive single user tasks well, such as
large scale cad, however in i/o intensive applications you will find that
the same limitations exist... ethernet and scsi only move data so fast.  If
you have 100 users on-line reading news, telneting, using ftp, etc... you
still haven't used the cpu for anything. i/o i/o i/o.  I'm not saying that
a RISC platform isn't great for multiuser applications, only that the
application doesn't fit.  You would be better off spending money on fast
i/o and using inexpensive processors.  The bus bandwidth limitations don't
go away when you add a faster cpu, and there is no configuration you could
put together for a large number of RISC machines that couldn't be done with
486 machines for this application.

George
-- 
George Wenzel                    |  Real/Time Communications
george@wixer.cactus.org          |  "faster, smarter and costs less..."
cactus.org!wixer!george          |  "Hardware solutions for the real world."
-----------------------------------------------------------------------------
Newsgroups: austin.public-net