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Mainframe definition

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Woodym1

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Aug 16, 2006
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Port Orchard, WA
My (tongue-in-cheek) concept of a "mainframe" is any computer system which weighed so much that it required a truck/tractor/forklift to move it into the computer room! In several pieces.

For example, an IBM S34 is NOT a mainframe, nor is a UNIVAC 1004. However a UNIVAC I or an IBM 705 II most assuredly are. The aforementioned systems are history and most current desktops can easily out perform them all, (In fact, I suppose my iPaq could!) but they were the mainframes which started the computer field. Put the US on the moon.

The old UNIVAC I, II and III were gigantic! Some, you could actually walk into. The IBM 705s the 7080, both were huge. The IBM 705 vacuum tube filaments alone probably consumed more power per day than my household per month! I sometimes dream (too much pasta and vino?) I'm troubleshooting one of these old systems again, with a trusty Tektronic 310 or a 545. Staring into a small green CRT, trying to find the sneak pulse or the non-kosher level. These tube computers could shock the crap out of you! (B+ could mean Brown and Served!) Maybe the dream was a nightmare?
 
Mainframe, continued

Mainframe, continued

To be serious, the term mainframe is somewhat dated. When I left the "mainframe" arena, (the nineties)the IBM 30xx systems were the big mainframes with the Enterprise 390 just appearing. I haven't a clue how many such systems remain.

I was fortunate enough to work on every kind of calculating device from mechanical calculators, thru tubes, descrete solid state computers and on into modern VLSI systems. Fortysome years in field service.

IBM had a series of Mini-s called the System 36 There was a 5361, 5362, a 5363 and a 5364 The 5364 was termed the baby 36 and had a much modified AT desktop as part of the two box system. Even though it ran a stupid RPG, It was far more capable than the huge room filling mainframes of yesteryear. It used ESDI hard drives. Various printers, and a late appearing 8 inch Floppy drive.
 
Yep, in 1968 I would use a Bendix G15 to warm up the room. The tubes were on huge hinges and you could swing them out. Reminded me of a large bathroom radiant heater. That "rotating drum RAM(?)" was very cute also.
 
Woodym1 said:
My (tongue-in-cheek) concept of a "mainframe" is any computer system which weighed so much that it required a truck/tractor/forklift to move it into the computer room! In several pieces.

For example, an IBM S34 is NOT a mainframe...
Click to expand...

Actually IBM's definition of the difference between a mainframe and "minicomputer" (which were mostly the System/34, 36, 38, AS400 level) was the *price*. If anyone wants to see a few S/34s & a couple of their printers being moved I have a group of photos from a few years back: http://www.gilanet.com/David/System34/ . Still have them sitting around where the picture set ends.
 
For the record...I consider an IBM Series 1 system to be a minicomputer system, even though each component is so heavy that I'd need a car jack to position them onto the rack shelves. These were IBM systems built in the late 70's early 80's.
 
Series 1

Series 1

I had not thought of the Series 1 in years! It was out of IBM's GSD. Even the USMC had a small ruggedized OD one. I always figured that under hostile fire, I might save my butt prior to worrying about my computer! Talk about a "luggable"... Two or more heavy pieces. (Wait sergeant! We can't advance our position yet, I just started payroll!)

I recall they ran AIX, or some flavor of UNIX, or IBM's EDX. It did have a large selection of I/O options.

Series 1; still a mini, although big blue may have categorized it otherwise.
 
I made a living (well, sort of) working on a Series/1 from 1984 to 1992. First one was in Las Vegas where I did accounting type programs in EDL (Event Driven Language) for the Hilton hotel chain. Then a few years at Baxter International in Glendale CA where they used it for production control and plasma accounting (blood plasma, that yellow liquid when you break open a burn). Baxter would pay donors (if you pay them, are they still a donor?) and make very expensive biological products out of the plasma. The Series/1 computers were still going strong in 1992 when Baxter sold the Plasma business to someone else. Out which point, I became a Novell Certified Network Engineer doing network crud.
 
Mini/mainframe continued

Mini/mainframe continued

Hey, I also was a Novell CNE! I am particularly proud of ace-ing the "Service and Support" exam. In the mid-90s.
I never took any of the the 4.X exams, I was too busy making a living after accepting "early retirement" from the big stuff. Minis and PCs were fun. I even slipped into some weird stuff such as ATMs, Banking, Industrial, Gas Analysis.

Thank God I'm retired!
 
Hmmm...I used to figure that if you were supporting hundreds of users, it was a midrange (mini) system, but if you had a thousand or more users, it would be a mainframe. Of course that mentality follows the world of "dumb" terminals from the earliest days. I'm not sure that even applies to modern systems. As an example, our AS/400 will support about 600 users. That is, about 600 directly connected Twinax devices--terminals & printers. On the other hand, thousands of people can connect to it over a conventional network in a client-server environment. So is it a Mainframe? Gut tells me no...

Yet, a system/390 (IBM) might be considered a Mainframe. Is it jus raw processing power? Or size? Even the 390 isn't a very big machine compared to a Univac I...

In the AS/400 (now I-Series) machines, a lot of tedious processing is pushed off to intelligen peripheral devices such as work station controllers and communication controllers. Does this architecture perhaps lead to the differentiation?
 
SwedaGuy said:
...As an example, our AS/400 will support about 600 users. That is, about 600 directly connected Twinax devices--terminals & printers. On the other hand, thousands of people can connect to it over a conventional network in a client-server environment. So is it a Mainframe?...
Click to expand...
I know what you mean - where does the differentiation lie. Our AS/400 (iSeries / System-i) at work has around 120 virtual environments, each with its own share of all the attached resources. Just the virtual environment we use for development often has several hundred users attached, loads of memory (not sure how much) and 4 terabytes of disk allocated. Even though it is a BIG machine, I still refer to it as a midrange (mini) system.

Steve
 
A mainframe is something that requires at least one dedicated MG set (preferably 400Hz 3-phase output) and a dedicated chilled water supply or more than one 50 ton HVAC unit (although liquid nitrogen will be considered as a substitute).

Anything else is a toy. :)
 
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According to the manual my s-100 "California Computer Systems 2200 Mainframe Computer" is a mainframe. So it must be true ;-)

Minis can function like mainframes, mainframes like micros...but the defining factor is the original suggested manufacturer intention IMHO.

The techno capabilities are a moving target over time, so you can't really use that. Same with the number of *possible* users.

I can say from my past work experience that IBM considered the Series 1 and AS/400 mini computers, same with the 36/38 series. IBM from a marketing perspective positioned mini's as the computers than ran offices, departments, or branch offices, and would then communicate with the "main headquarters" mainframe installation.

I am pretty comfortable with that definition as a general rule.

bd
 
For me a proper mainframe has an engineering panel with at least two dozen switches and another two dozen lights.
The other requirement is that all hardware must be stored and run in individual modules that are no smaller than a washing machine or consist of at least three fully filled racks (however this only applies to PDP systems).
 
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