18 May
2005
18 May
'05
8:28 p.m.
On Tue, 17 May 2005 07:28:52 -0700 (PDT)
Vintage Computer Festival <vcf at siconic.com> wrote:
On Tue, 17 May 2005 Saquinn624 at aol.com wrote:
Interesting way to skew it, but it 'breaks' somewhat with certain older
microprocessor based systems. My Altos 586, for instance, has 5 serial
ports all designed to host a user on a dumb terminal. But it has an
8086 processor. So it's explicitly a multiuser machine, but with a
single chip micro.
An interesting 'dividing line' that I like to use is 'does a keyboard
plug into it?' Is it primarily designed as a single-user workstation,
with keyboard and display attached?
The dividing question of all-discrete-logic design is also a good
dividing point. Minicomputers have logic-gates for more than 'glue'
functions and shuttling data between LSI chips.
There's even a 'dividing point' in this within consumer 'pee-cee'
hardware, one that I think can be used as a 'classic/non-classic'
divide. The old 'XT' type machines used a few stock off-the-shelf
8xxx-series LSI chips but no large scale custom chips at all. The
earliest 'AT' type systems follow this design as well. The earliest
'full-size AT' motherboards feature all TTL logic plus off-the-shelf
8xxx-series LSI chips. This era ended when 'custom VLSI chip-set'
design kicked in, and it was essentially the 'end of the era' for easily
repairable 'Pee-Cee' designs. The first few generations (up to the
PC-AT) of the IBM design were fully 'open' to tech people, that changed
around the time of the higher-end 386 systems.
One thing that I have been wondering for a while
is what the current
definition of minicomputer is.
It used to be contrasted with microcomputers, the telling difference
being a multichip processor implementation versus a single-chip
microprocessor [if so, are the POWER1 and POWER2 processors
minicomputer processors?] but now, with microprocessors being used
in mainframes (and even on-topic mainframes) is this distinction
meaningless [i.e. should the designation "microcomputer" in its
size/power context be replaced with something else?] and, if so,
does the [whatever micro becomes]/mini/mainframe become a question
of mass (>700 lbs mainframe, >100 lbs mini, <100 lbs [???]), or
history (the HP3000 started life as a mini, therefore the spectrum
models continue as minis . . .), or does the venerable minicomputer
cease to exist? any other ideas?
We had to address this issue for the VCF. In deciding what classes to
create, we decided on Microcomputer and "Mini, Multi-User, or Larger
Computer", with the following definitions:
1. Microcomputer
A "microcomputer" is defined as a computer having no more than two
microprocessors used for general purpose processing within the
computer. For the purposes of this class, a "microprocessor" is
defined as a central processing unit comprised of not more than 4
individual LSI intgerated circuit on a single board, with the entire
ALU being contained within a single integrated circuit.
2. Mini, Multi-User, or Larger Computer
This class encompasses all computers that were intended primarily to
be used by multiple simultaneous users (i.e. mainframes), or that were
smaller (in terms of size and power consumption) than mainframe
computers but utilized a central processing unit comprised of many
discrete or integrated circuit components either on a single carrier
or across multiple carriers.
Comments welcome.
--
Sellam Ismail Vintage Computer
Festival-------------------------------------------------------------
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