mini versus micro?

[Julian Wolfe]

> -----Original Message-----
> From: cctalk-bounces at classiccmp.org 
> [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Rob O'Donnell
> Sent: Thursday, May 19, 2005 4:04 AM
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: mini versus micro?
> 
> At 20:08 18/05/2005, Ethan Dicks wrote:
> 
> >On 5/18/05, Rob O'Donnell 
> <classiccmp.org at irrelevant.fsnet.co.uk> wrote:
> > > The worst processor/user ratio I think I encountered was about 50 
> > > users sharing a 486dx50.. It was in a rack case, in the 
> top 6" of a 
> > > 4' rack, the rest being blocked in empty space except for 
> a UPS sat 
> > > in the bottom.  The users most definitely called it "the 
> mainframe" !
> >
> >Worst processor/user ratio for PeeCee-class equipment, or on a 
> >per-cycle basis?
> 
> I was thinking specifically of the PeeCee based stuff.  I did 
> have for a while an ex-customer "Microfive" machine, 8088 
> based, 12 serial ports on the back, no kb or video, and not 
> PC architecture.  With maximum users that would have been worse...
> 
> Thinking about it, though, some of the VAX (11/780) and 
> own-brand machines I used years back at Ferranti would have 
> been far less cycles/user.
> 
> [snip]
> >So in the great mini-vs-micro debate, once one is talking about later
> >16 and 32-bit minis (early 12 and 16-bit minis do tend to have one 
> >medium-performance I/O bus), I'd have to say that I/O 
> architecture has 
> >as much to do with the definition as the number of processors.
> 
> I think the micro/mini is a pretty hard distinction to make 
> when talking about current hardware; the technologies 
> cross-pollinate!  Even in old stuff, it certainly sounds like 
> it's more of a marketing term rather than a technical 
> definition - The "small enough for a department to afford" 
> meaning of mini feels best to me for the older machines.
> 
I'm pretty sure there's no minicomputer class of system anymore.  I believe
there are systems referred to as "Entry level", "Enterprise", "Mid-frame",
and "Mainframe"

I agree here though, it's all marketing.  The only actual distinction you
can make hardware-wise is between microprocessor and non-microprocessor
based systems...a good example of this is DEC, who called every QBUS machine
a microcomputer.

I believe the proof in the pudding here is that there are now hundreds of
owners of "personal minicomputers" and even a few with "personal
mainframes."

There was some strange crossover material here too, like 1973's GT40
graphics workstation, which sat on a desk, and had its own CPU and whatnot,
that it shared with the 11/05...however, the 11/05 model was designated as a
minicomputer, even though some of the lowest end 11/05 models ran a single
user programming system off cassettes...if that's not a "personal
computer"....I don't know what is.

So to recap, in marketing terms, a personal computer is:
A computer architecture designed with a single user *in mind*.
A minicomputer is an architecture with a multiuser system in mind.
A mainframe is an architecture with a large number of multiple users in
mind.

How can I illustrate the difference between mainframe and mini?  Back in the
day, I know there were some businesses that ran each of their engineering
areas each on a different mini, then the finance on another, administration
on another, etc.  I honestly believe the marketing of the minicomputer to be
only groundbreaking in that it was the first step toward decentralized
computing...again, that's only *marketing* wise.

Of course, if you're DEC, you don't know what you're selling, so it's all
moot ;)

End rant :D
Julian

> Rob 
> 
>