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View Full Version : What are some common models of mini's and mainframe's?



punchy71
May 4th, 2015, 10:07 AM
Hello,
I know next to nothing about mini's and mainframes, but I still find them somewhat interesting nonetheless.
What are a few of the most common models from the past?
In recent times I've heard a lot of old-school computer people discuss and bring up the subject of their beloved "PDP-*" from back in the good old days. So, since I was never around that long ago, I'm assuming that the "PDP-fill in the blank here" is one of the more common models? And that "PDP's" were pretty much the king of mini's and mainframes. But, weren't there other common models too?
Thanks

krebizfan
May 4th, 2015, 10:34 AM
King of the mainframes was likely the IBM 360 series which became the basis for a very long successful run of related designs. Earlier IBM mainframes, their US competitors (the so-called "7 dwarfs"), European competitors and the near clones from Amdahl filled in the rest of the market for big iron. Whatever Seymour Cray was working on in any given year was that year's example of a supercomputer and no other supercomputer mattered.

DEC's lineup was pretty much the definition of mini-computers with the PDP-11 managing to be the surprise "does-it-all" concept with different models competing against PCs and workstations at the low end and competing with mainframes at the high end.

Chuck(G)
May 4th, 2015, 11:26 AM
The variety was endless--as were the vendors--and were sub-categories. For a time, CDC and then Cray dominated the supercomputer business, but there were lots of other contenders. It'd be a big job intemizing the models, much less the marques, in minicomputers.

Tor
May 4th, 2015, 11:51 AM
I've never seen a physical PDP of any type. The DEC minis I saw and used were various VAX types. The minis I used the most were produced from 1969 up to the early nineties (although there was a final system delivered in 2001!): Norsk Data NORD-10, ND-100, ND-110, ND-120 (all 16-bits), ND-500 and ND-5000 of various types: 530, 550, 570, 5400, 5700 (all 32-bits).

-Tor

g4ugm
May 4th, 2015, 01:39 PM
It depends on what you mean by "past". IBM or "Big Blue" as they were known produced what I guess were the definitive mainframes. Starting with a range of incompatible 700 and 700 machines in the 50's and 60's then as some one at the top said the System/360 which was a range of upwardly compatible Mainframes, Superseded by the compatible System/370 in the 1970's, and the then 43xx, 3080 and 3090, which were again 360 compatible. Even the latest "Z" boxes will run S/360 user mode code. Some info on the 3080 here:-

https://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP3081.html

Apart from being software compatible IBM peripherals could also be attached to most of its mainframe range by virtue of the IBM Standard Channel , known as "Bus & Tag" as it has a pair of mutli-way cables, one called BUS and the other TAG. Early versions were 1M/Byte second, so about as fast as early Ethernet as there is no slow down for contention. Later versions were 2, 4 and 6 M/Bytes per second.

http://en.wikipedia.org/wiki/IBM_System/360#Channels

Various anti-trust decrees (google them) ensured that IBM published detailed interface specification and ensured that there was a huge range of compatible mainframes and peripherals. Gene Amdahl who was one of the S/360 designers left and founded his own company that produced the "470" series, but Fujitsu, Hitachi also produced clones. Many companies also produced peripherals including not only tapes and disk drives, but also communications controllers and specialized devices.

Other mainframes I encountered were ICL 1900 and 2900, Honeywell H3200 and L66 (originally the GE6000 series), CDC and Boroughs machines.

IBM also produced incompatible smaller machines, notably the 1130 and 1800 which were small machines for scientific use, System/3, System/36 and System/38 for business use, but I think it was their mainframes that had the most influence.

g4ugm
May 4th, 2015, 01:42 PM
The variety was endless--as were the vendors--and were sub-categories. For a time, CDC and then Cray dominated the supercomputer business, but there were lots of other contenders. It'd be a big job intemizing the models, much less the marques, in minicomputers.

Ooh yes, lots of specialist makers, Pr1me, Data General, Varian, Singer, CTL who produced the Modula 1 in the UK, the UK GEC....

Doug G
May 5th, 2015, 02:37 PM
Data General's Nova and Eclipse minis were quite common in the 70's.

Oops, I see DG was mentioned already. I serviced CDC SMD drives which were widely used as storage for mini systems, and fairly often ran across HP minis. Even IBM Series/1 minis.

KC9UDX
May 5th, 2015, 02:50 PM
I think it would be more interesting to list the obscure ones no one talks about. I had ( :( ) a Quantel and several Wangs at one time. No one ever talks about those. I don't even know the details of the Quantel. It most likely ran Primos.

ClassicHasClass
May 5th, 2015, 08:51 PM
Very briefly worked near (though sadly never on) an Encore system before it got replaced with an HP/UX box. I stole some tape reels from it when it was being decommissioned and they're on display in my retroroom.

And anyone who was on QuantumLink back in the day was using a Stratus system (which remained in the back corner of the server room through the early days of AOL as well). They're still around. Unisys continues the Burroughs line, too.

Chuck(G)
May 6th, 2015, 06:49 AM
To resurrect an old theme, what was a minicomputer? Was a System 360/20 one? I don't recall IBM ever applying the term to it.

There were a lot more makers back in the big iron days--all one need to is prowl the Bitsavers archive--and it's nowhere near to complete. But there's lots of good information there on machines that have faded from memory, such as the Philco System 2000, back when Philco also made home appliances, radios and TVs--and was a division of Ford.

Your friends who collect early Packard-Bell PCs might be interested to learn about the real Packard-Bell. They might well have a PB 500, but I'll wager that they don't have a PB 250.

krebizfan
May 6th, 2015, 07:17 AM
Gordon Bell makes a specialty of writing historical articles about minicomputers with frequent definitions such as http://ethw.org/Rise_and_Fall_of_Minicomputers

Minicomputer was started as a DEC marketing term to showcase their systems as modern and sexy (playing off the mini-skirt) which then got used by the trade press for the segment of computers priced between $10,000 and $100,000. Inflation kept that definition useful for many years longer than Moore's Law should have allowed.

Chuck(G)
May 6th, 2015, 08:43 AM
Not to forget the almost-forgotten term "midicomputer". c.f. typical usage in press (https://books.google.com/books?id=TgGty5HMPj0C&pg=RA1-PA6&lpg=RA1-PA6&dq=%22Midicomputer%22&source=bl&ots=9hq7YOuFve&sig=VMYolo2mIpSqEjL3wYujZAYq5Ws&hl=en&sa=X&ei=AkVKVfKcEsvGogSl9YHQBg&ved=0CDUQ6AEwBA#v=onepage&q=%22Midicomputer%22&f=false).

The term just never caught on.

ClassicHasClass
May 6th, 2015, 02:36 PM
Isn't the Yamaha CX5M a MIDI-computer?





I'll get my coat.

Chuck(G)
May 6th, 2015, 05:08 PM
Heh. You'll get far more hits from "MIDI Computer" than you will with "midicomputer". If the OP takes a look at the Computerworld issue I linked to from 1975, he'll get a good feel of what the heyday of minicomputers looked like--and how many brands and systems have been forgotten about since then.

Leafing through the issue, I was reminded of the old joke about "Greyhound Computer uses touring machines."

https://www.glabarre.com/item_images/greyhound.jpg

Beerhunter
May 9th, 2015, 07:13 AM
To resurrect an old theme, what was a minicomputer? Was a System 360/20 one? I don't recall IBM ever applying the term to it.

Internally we refer to 360/20 and 360/40 as "low-end". 360/40 was the first System/360 to actually power up. (At Hursley Park, England.)

IBM's first "true" mini was System/3 (1969) known within IBM as a "mid-range" computer.

Chuck(G)
May 9th, 2015, 07:47 AM
That's mostly a matter of time and terminology. A Packard-Bell PB250 could be called a "minicomputer" (1959?); but the term didn't exist then. Same for the Model 20 or CDC 160A or a number of other "small" machines.

billdeg
July 1st, 2015, 04:32 AM
I agree with the person in this thread that suggested you read up about more than just Digital in order to get a balanced perspective. I love DEC stuff and support a number of their machines. Mostly because they're easier to find and support than things like Honeywells, Varians, and Novas.

First off, IBM sold more minis than everyone combined in the 60's and early 70's. Digital was a blip in the overall sales $$ total until much later. Only those who say "it has to be a Digital for it to be a mini" could argue otherwise. Check out the CDC 1700, RCA Spectra line, IBM 360/20 or 30, UNIVAC 418-II, and 418-III. To name a few. I think it's fair to call these minis and these sold a lot back then.

You really need to do a lot of reading about the computer business starting from the late 50's to get a feel of what people were writing about then, how they saw computers. See if you can find Computer World newspapers from 1960's. Also see if you can find sales figures and learn about the top sellers in the small mainframe/mini market from the 1960's when minis were in their heyday. Don't get hung up about what we today call/delimit mini from mainframe. Anything with contemporary specs "less than" an IBM 360/50 from the mid 60's is a mini in a general way.

I think our perception today about the past over emphasizes the role of the Digital PDP systems at the expense of the other manufacturers. Same goes for Apple - both is over weighted when you take a look at the sales figures. Not that either weren't important, just that the balanced commentary isn't there.

Compare sales figures and you'll see Digital did not really start selling/growing its business huge until the mid/late 1970's. There were probably 10 companies selling more computer systems roughly described as "mini" in the 1960's than Digital. Look it up.

My personal favorite obscure mini is the 1956 Royal MacBee LG-30.
http://vintagecomputer.net/browse_thread.cfm?id=596

Agent Orange
July 1st, 2015, 06:43 AM
The government area that I worked in back in the 80's, anything that had parts and boards sliding in and out of rack was considered a main frame. Some were larger than others.

ClassicHasClass
July 1st, 2015, 07:08 AM
Q. What's the difference between a micro, a mini and a mainframe? Courtesy of cctalk:

(Fred Cisin)
carry - micro
handtruck - mini
forklift & union moving crew - mainframe

lose a screw in it - micro
lose a screwdrive in it -mini
lose a CE in it - mainframe

downtime pisses off somebody - micro
downtime pisses of a bunch of people - mini
downtime pisses off everybody - mainframe

mains outlet - micro
mains circuit - mini
mains account - mainframe

neighbors are amused by your collection of micros
neighbors are worried about your collection of minis
neighbors are terrified of your collection of mainframes

wife complains - micros
wife leaves - minis
wife has not been seen since . . . - mainframes

(Doc Shipley)
And somewhere between mini and mainframe is where, based on your
electric bill, the DEA shows up to inspect your hydroponic garden.

This did actually happen to an acquaintance.

(Sean Conner)
Back in the late 90s I worked at a company that had a Stratus. If you
rebooted the machine, within twenty minutes, the Status company would call
up asking if there were any issues we were experiencing and should a
technician be sent out?

There's also the apocraphyl story of a new fan unit showing up at the
office---the Stratus noticed one of the existing fan units was marginal and
had ordered itself a replacement.

So perhaps it is the service level that makes a mainframe a mainframe.

KC9UDX
July 1st, 2015, 08:36 AM
After some thought, I think the only thing that really distinguishes a Mainframe, is EBCDIC.

Chuck(G)
July 1st, 2015, 08:42 AM
So, what collector has an MG set installed to supply 400Hz 3-phase power to their mainframe, as well as a chilled water supply?

Agent Orange
July 1st, 2015, 08:47 AM
. . . 400Hz 3-phase power to their mainframe, as well as a chilled water supply? Sounds like the average avionics shop aboard any U.S. aircraft carrier. :p

Chuck(G)
July 1st, 2015, 08:55 AM
...and very typical for a real 60s...80s mainframe.

Eudimorphodon
July 1st, 2015, 03:01 PM
I have to say I'm surprised at how many random museums I've found that have one of those old C-shaped Crays in their collection. Of course, no one actually has a *working* one...

Chuck(G)
July 1st, 2015, 03:14 PM
Cray Is? How many of those museums could afford to supply one with power and cooling? Even a Cray 2 would be interesting. Both tough to service with lots of custom silicon. How many museums could keep a real ETA 10 going? Power and liquid nitrogen--and of course, lots of custom CMOS.

Eudimorphodon
July 1st, 2015, 03:36 PM
Oh, I certainly wouldn't *expect* that a museum could keep one running, it's just a tiny bit sad to see Cray Is reduced to being fashionable couches. :)

(Years ago I actually got to sit on one.)

Chuck(G)
July 1st, 2015, 04:29 PM
Well, there is/was a guy who was implementing much of a Cray I in FPGA. Don't know what became of the project though. You could tuck the PCB for that under one of the cushions.

cruff
July 1st, 2015, 05:23 PM
... it's just a tiny bit sad to see Cray Is reduced to being fashionable couches.

At NCAR we have Cray-1A serial number 3 sitting down the hall from my office as an exhibit. The children love to stand in the middle of the "C" and have their pictures taken. On the wall nearby is a exhibit about Seymour Cray and his life. There is a poster next to the Cray comparing it to an iPhone 3. The iPhone wins in all categories, except for volume, mass and power consumption. :(

ClassicHasClass
July 1st, 2015, 05:28 PM
Man, I would love one. Even just a baby replica one that could be an appropriate loveseat, if I can find an appropriate geek lady. :)


So, what collector has an MG set installed to supply 400Hz 3-phase power to their mainframe, as well as a chilled water supply?

My servers do have their own A/C circuit in the room next door ...

NeXT
July 1st, 2015, 06:44 PM
I have to say I'm surprised at how many random museums I've found that have one of those old C-shaped Crays in their collection. Of course, no one actually has a *working* one...

There are no working Cray's of the early generations left working in the world. Through the disposal of external components, cutting of cables and the removal of boards as novelty trinkets there is simply not enough parts remaining to build a working machine, especially the Cray-1.


Man, I would love one. Even just a baby replica one that could be an appropriate loveseat, if I can find an appropriate geek lady.
The basic frame of the Cray-1 is really easy to replicate. It's just two different sizes of wedge-shaped blocks bolted together into a C-shape. Once you have those jigged you can rather quickly produce frame segments.

Chuck(G)
July 1st, 2015, 07:02 PM
At NCAR we have Cray-1A serial number 3 sitting down the hall from my office as an exhibit. The children love to stand in the middle of the "C" and have their pictures taken. On the wall nearby is a exhibit about Seymour Cray and his life. There is a poster next to the Cray comparing it to an iPhone 3. The iPhone wins in all categories, except for volume, mass and power consumption. :(

Let's see an iPhone read a 9-track tape or punch a box of cards...

commodorejohn
July 1st, 2015, 07:13 PM
I imagine the Cray was a bit less locked-down, as well.

Chuck(G)
July 1st, 2015, 07:21 PM
I imagine the Cray was a bit less locked-down, as well.

Heh. :thumbsup:

Beerhunter
July 2nd, 2015, 02:28 AM
After some thought, I think the only thing that really distinguishes a Mainframe, is EBCDIC.
Nope. All the IBM minis ran it too. e.g. S/34, S/38, 8100 etc.

cruff
July 2nd, 2015, 05:17 AM
Let's see an iPhone read a 9-track tape or punch a box of cards...

Perhaps with a suitable serial or USB interface, it might! But strictly speaking, the Crays we had at NCAR neither directly read a 9-track tape nor punched a box of cards. All of that piddly stuff was handled by "lesser" computers.

KC9UDX
July 2nd, 2015, 06:04 AM
I have a computer that runs on 3-phase power. But it only has one processor, and it's a uP, so, even though it wasn't called Microcomputer at the time, I suppose that's what it is.

KC9UDX
July 2nd, 2015, 06:05 AM
Nope. All the IBM minis ran it too. e.g. S/34, S/38, 8100 etc.

Right, but, all "Mainframes" natively use EBCDIC. Not all computers that use EBCDIC are "Mainframes".

Chuck(G)
July 2nd, 2015, 07:35 AM
Right, but, all "Mainframes" natively use EBCDIC. Not all computers that use EBCDIC are "Mainframes".

Really? I'm not aware of a CDC or Cray mainframe natively using EBCDIC. In point of fact, the large CDC Cyber systems through the 1980s used 6-bit display code. On the other hand, there were some small machines that did use EBCDIC (e.g. Two-Pi or even the Displaywriter, an 8086 box).

Chuck(G)
July 2nd, 2015, 07:39 AM
Perhaps with a suitable serial or USB interface, it might! But strictly speaking, the Crays we had at NCAR neither directly read a 9-track tape nor punched a box of cards. All of that piddly stuff was handled by "lesser" computers.

That was my point, very early in this thread. One distinguishing feature of a mainframe is the peripheral support--and most minis (even a VAX 11/780) didn't have it, much less an iPhone. Cray didn't want to design his own peripheral controllers, so he provided a big I/O channel. CDC, on the other hand, used their own I/O processors.

Beerhunter
July 2nd, 2015, 09:00 AM
Right, but, all "Mainframes" natively use EBCDIC. Not all computers that use EBCDIC are "Mainframes".
Good try but I think that you are on a loser here. :-)

KC9UDX
July 2nd, 2015, 09:03 AM
Good try but I think that you are on a loser here. :-)

Beats me. I recall IBM claiming only IBM machines were "Mainframes".

ClassicHasClass
July 2nd, 2015, 09:15 AM
That sounds like a very IBM thing to say. :)

Chuck(G)
July 2nd, 2015, 09:55 AM
Well, other than timing, I suppose that a 1401, 1130 or 1620 might be considered a "minicomputer"--but the term didn't exist when those products were introduced.

That's the problem with terms of art--timeliness.

lowen
July 2nd, 2015, 10:25 AM
...
(Sean Conner)
Back in the late 90s I worked at a company that had a Stratus. If you
rebooted the machine, within twenty minutes, the Status company would call
up asking if there were any issues we were experiencing and should a
technician be sent out?

There's also the apocraphyl story of a new fan unit showing up at the
office---the Stratus noticed one of the existing fan units was marginal and
had ordered itself a replacement.

So perhaps it is the service level that makes a mainframe a mainframe.

You get this with EMC and their storage arrays, which are just specialized computers. If you're set up to do so, they will send you a replacement drive before you know you have one on its way out thanks to the array's telemetry and 'call-home' messages. So I'm not sure service level makes something qualify as a mainframe..... and EBCDIC certainly isn't one of the criteria..... :-)

krebizfan
July 2nd, 2015, 10:56 AM
For the OP's purpose, the best place to define the difference between mainframe and minicomputer would be where the coverage and ads were in Computerworld. Computerworld had clearly defined sections with different reporters covering each segment. Ads went to the matching segment except for very expensive cover placement. Microcomputers got their own sections once that market expanded enough; before, microcomputers got the occasional short blurb showcasing the adorable nature of these tiny companies pretending their tiny boxes could be used as computers.

Companies would try to slide to whichever segment would generate the most revenue. Database providers tried to move upmarket because people pay more for software running on big iron. Lab systems tended to be listed more as single user systems because scientists hate sharing equipment. Same hardware, different ads, different marketing goodies, different logos.

Chuck(G)
July 2nd, 2015, 11:11 AM
Well, consider the lowly 1401. Originally used as a replacement/enhancement for unit record gear; promoted to a "real" computer via RPG, then demoted to printer driver on 709x "SPOOL".

Beerhunter
July 2nd, 2015, 11:19 AM
Beats me. I recall IBM claiming only IBM machines were "Mainframes".
I worked for IBM for thirty five years and I do not recall IBM saying anything of the sort.

Remember for most of its computing heyday IBM was under various Sherman Antitrust Consent Decrees simply for being so big (some estimated 70% of the market) and so IBM was uber-careful not to make statements like that because that would be admitting to be a total monopoly and so subject to even more constraints.

KC9UDX
July 2nd, 2015, 03:20 PM
It was a recenr statement, as in within the last decade, I think. I'll have to see if I can find it.

ClassicHasClass
July 2nd, 2015, 04:13 PM
You get this with EMC and their storage arrays, which are just specialized computers. If you're set up to do so, they will send you a replacement drive before you know you have one on its way out thanks to the array's telemetry and 'call-home' messages. So I'm not sure service level makes something qualify as a mainframe..... and EBCDIC certainly isn't one of the criteria..... :-)

My POWER6, which is definitely not a mainframe, will also do this (except it's not hooked up to a phone line, and I eventually turned the feature off since I ain't paying IBM's consultant rates).

But back in the day when dinosaurs ruled the earth and IBM still sold personal computers, I think that was as good a distinction as any.

Beerhunter
July 3rd, 2015, 06:32 AM
We only really started put IBM boxes online to IBM with the advent of the 3080s in the 1980s. They could talk to the Plant of Control - Montpellier, in EMEA - and that had to be initiated by a CE.

MikeC
January 25th, 2017, 10:11 AM
Well, other than timing, I suppose that a 1401, 1130 or 1620 might be considered a "minicomputer"--but the term didn't exist when those products were introduced.

Jumping in somewhat late.....

I used a 1620 at college, and later Prime & DEC "minis" for work when that was the way they were described. No way would I call a 1620 a minicomputer -- I expect at least a multi-user interactive OS, not one where you drop cards into the reader then watch the pretty lights until the printer clatters the core-dump you just caused. Not sure I'd call it a mainframe either, more like a very early single-user computer, albeit not a desktop PC.

Mike