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Pound for pound the best mainframe


Experienced Member
Mar 1, 2023
South UK
Ok in boxing there is a phrase pound for pound, working across different weight classes.

So not actually focusing on the weight of the item but across different ages.

What is the best mainframe and why? With any of this it is open for interpretation. You could say the design is better, set the tone for the future. Etc
Everyone will have their own opinion on what is best. You get the same problem when asked what is the best sounding muffler to buy. Everyone has what they like or don't like. So it's very subjective. I haven't used enough of the older mainframes to even hazard a guess.
The one with the cheapest software licenses for the applications you (the company) is going to run on it.
I've always been fascinated by the seemingly immortal mainframe lineage birthed by the IBM System/360. From the start S/360 was conceived as a scalable family going all the way from very large mainframes down to (at the time) fairly modest almost-minicomputers, and it also had as a design goal to unify the split between IBM's "Business" and "Scientific" mainframe lines. (Up to this point IBM had built completely different and incompatible machines for different kinds of applications.) As a result the S/360 ended up as an incredibly flexible modular platform, that even had the capacity to emulate some of their older mainframe lines using a combination of software and loadable microcode.

The architecture pioneered a lot of things which became industry standards, like eight bit bytes, 32-bit words, byte-addressable memory, etc. The S/360, starting with the Model 67, also introduced the concept of address translation and virtual memory to IBM mainframes; it didn't become standard until the System/370 in the 1970's, but as a result of it IBM's mainframes became all about using virtualization to allow a single machine to run different generations of software and even multiple different operating systems simultaneously. Software written for the S/360 will still run on a modern zArchitecture IBM mainframe thanks to virtualization, and of course we wouldn't have the modern concept of cloud computing without it either.
Fifteen or twenty years ago it was cheap and easy to buy into the DEC PDP-11 way of life but those days are gone now. What hardware is way high price and too many people out there are taking what ever they get and chopping it up because the components are worth more then the whole. I did the 11 because back then the 8 was already selling for huge money. The DEC equipment has the benefit of many other users for advice, lots of software and people knowledgeable of that software and systems and they are large but not so large requiring three phase or 240-volt sub feeds.

I sold off my DEC collection a couple years back, freed up a lot of flor space. I have moved on to Data General NOVA platforms. Been playing around with ROLM military systems and so far, they have been cheap and have been a little successful in documentation and software but still after five or ten years have not been able to get a copy of NOVA Basic!

I think maybe the best bargains around right now may be first generation PC systems like 286, 386 or 486 hardware being you can have endless amounts of fun in DOS and old DOS applications, also feel that maybe S-100 base technology may be a good value right now and you will defiantly be learning all about structure, machine language and how to write macros with that hardware but with large systems you are going to be somewhat limited. They stopped building huge mainframes a long time ago so there is less and less out there. DEC VAX and Micro VAX is not stupid crazy price but just like running Windows Server the VAX hardware is not fun or real useful unless your using it in a multi user environment.

Would be interested to see what direction you finely go.

What is the best mainframe and why? With any of this it is open for interpretation. You could say the design is better, set the tone for the future. Etc
The best mainframe is one you can actual own and afford to power and afford to cool and afford to maintain.
Realistically this means an emulated mainframe for the vast majority of us.
"Hercules" for IBM /3x0 or "Desktop CYBER" for CDC 6000 and CYBER series come to mind.
UNIVAC I, or Ferranti Mark I, because they were pretty much the only game in town at the time.
Basically, the question is nonsense, as you didn't specify a particular set of applications.
There is always a weight based comparison and the prototype of the Hercules emulator on an iPhone may provide the maximum per pound.
As interesting as I find the S/360 (and its successors) in *theory* I can't honestly imagine wanting one around the house (er, I guess make that "mansion" for most models) nor finding any fun recreational use for one. If money and space were no object a large PDP-11 running UNIX or something I could sort of get into as representing a massive ancestral dinosaur version of a modern workstation/server, but IBM mainframes are the domain of the data processing high priests and their arcane operational rituals are a mystery to me.
A PDP-11/74 should probably qualify by sheer mass. Technically if it ain't got swing-out frames it doesn't meet the original definition of "mainframe", however AFAIK the era of "frames" ended OOA the mid/later 60's regardless of horsepower.
Control Data still developed new CYBER series mainframes in the early to mid 80s. Last I worked on one was 1988.
The IBM 4300 was released in the early 80s. The 3090 mid to late 80s.
All these were physically large mainframes.
Technically if it ain't got swing-out frames it doesn't meet the original definition of "mainframe",

Do you have a picture of what precisely you mean by “swing out frames”? There was a lot of diversity in how early large computers were assembled; some have at least the CPU in some kind of monolithic structure (I’ve seen some that are reminiscent to something like a locomotive, which some sources credit the origin of the term), but a lot of other early large computers are just rows of telco racks… which are also called “frames”. (And the “main frame” would be the row of racks with, pick your poison, the ALU, the control panel, the plugboards, whatever.)
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