Inside an IBM/Motorola mainframe controller chip from 1981

http://www.righto.com/2024/07/ibm-3274-keystone-chip.html

by todsacerdoti • 2 years ago

131 92 2 years ago

righto.com

kens8• 2 years ago

Author here if anyone has questions...

java-man2• 2 years ago

Thank you for your work, every article brightens my day!

Every time I look at the chips from 70s and 80s, I notice how huge the features are. Was that determined by the current stepper technology at the time, or by the fact that people drew the early designs by hand?

Or am I totally wrong and the chips are always at the limit of the contemporary technology?

kens8• 2 years ago

The feature size on chips has steadily shrunk from 10 µm for the Intel 8008 to a few nanometers nowadays. The feature size is determined by the limits of contemporary technology, which steadily improves as described by Moore's Law. Many different technological aspects need to improve to shrink the features, from the design techniques to the optics to the chemical processes.

bobmcnamara• 2 years ago

Or am I totally wrong and the chips are always at the limit of the contemporary technology?

I can chime in here. There are many things that determine the feature size.

There is the process limit, yes, and if your needs are simple digital logic, that's often going to be the density limit.

But if you need NOR flash, there's a stability limit around 40nm process node. You can use smaller transistors for everything else, but soon the NOR is most of the chip.

But what if you need a 1 Amp FET in your PMIC? Well, that won't shrink with process node at all, so maybe a cheaper process node is better to use.

It really depends.

renewedrebecca• 2 years ago

Really appreciate the work you do on documenting these chips. It's awesome to see how the stuff I only worked with from the programming side works at the hardware level.

kens8• 2 years ago

Thank you to you and all the others in this thread for your positive comments. I almost didn't write about this chip because it is so obscure, so it is encouraging that people are reading it.

kaladin_12• 2 years ago

Thanks a lot for the work you do in documenting these chips.

I am a software engineer that mostly sell fullstack skills. After reading your article on the chip that powers Montreal subway, I developed an interest in chip architectures.

I just finished these two books, The Soul of a New Machine by Tracy Kidder and Hackers by Steven Levy, they are historical books on computer design.

If you have other good reads that a web dev can use in testing the waters I would appreciate.

beachy• 2 years ago

The Mythical Man Month by Fred Brooks is always worth a read. It's now an ancient tome (e.g talk of how much storage space comments take up) but there is a lot of wisdom there and it certainly ticks the historical box. It's one of the only books I re-read regularly.

kragen9• 2 years ago

if you want to understand chip architectures, work through the elements of computing systems (aka nand to tetris). it walks you through implementing your own cpu, gate by gate, plus an operating system, compiler, and tetris game, in a way tested to successfully fit inside of a single-semester undergraduate class. their hardware designs are pretty weird (their hdl looks nothing like any hdl you can actually synthesize hardware from, their descriptions of how gates work are oversimplified, and their instruction set architecture is pretty similar to the eclipse that kidder was writing about but completely unlike any current design) but that isn't really important

after completing the work in that book and raising investment capital for your company, you can honestly call yourself a fullstack engineer

— arm —

the best architecture to write assembly for is the arm—the original one, not thumb, which is a bit of a pain—and arm is also only slightly more complex to build than the fake-ass architecture in nand2tetris, and quite a bit faster. if you already know any assembly language, including the nand2tetris one, the best introduction to arm might not actually be any current tutorial but rather the vlsi arm3 datasheet from 01990 https://www.chiark.greenend.org.uk/~theom/riscos/docs/ARM3-d... which has a summary of the instruction set on p.1-7 (9/56) and a fully complete description on pp.3-12 to 3-43 (19/56 to 34/56)

as you probably know, the vast majority of the cpus around you run the arm instruction set or its thumb variant, although amd64 and aarch64 (arm64) are also significant. the current arm architecture reference manual describes all the new instructions that have been added since arm3, as well as thumb, which makes it enormous and intimidating, with a very low signal-to-noise ratio

if you don't know any assembly, the three best actual tutorials for arm that i've found are https://www.coranac.com/tonc/text/asm.htm (aimed at the gameboy advance), https://devblogs.microsoft.com/oldnewthing/20210531-00/?p=10... (aimed at windows 10, thumb-only), and https://azeria-labs.com/writing-arm-assembly-part-1/ (aimed at crackers). these are all much longer than the relevant part of the arm3 datasheet but will guide you through how to actually use the things

— teensy programs —

perhaps the best introduction to writing assembly language in general on current systems is https://www.muppetlabs.com/~breadbox/software/tiny/teensy.ht..., which is not really focused on assembly at all, but on understanding how the interface between the operating system (i386 linux in this case) and user programs work, which just happens to be at the assembly-language level

it's also a lot more fun to read than any of these except maybe kidder and levy

— risc-v —

the risc-v architecture is very similar to arm but simpler; however, it's a little more of a pain to program, and there aren't any high-performance implementations of it out there, something that's likely to change in the next few years. the part of the risc-v manual https://riscv.org/wp-content/uploads/2019/12/riscv-spec-2019... that corresponds to the part of the arm3 manual i recommended above is chapter 2, rv32i base integer instruction set, pp.13–29. this reflects an additional 30 years of computer architecture lessons from arm and its successors, and a lot of those lessons are helpfully explained in the italic notes in the text. geohot livecoded a full implementation of risc-v in verilog on his twitch stream a few years ago, so you can literally implement risc-v in an afternoon: https://github.com/geohot/twitchcore

gcc can compile to risc-v and generates decent code, and linux can run on it, but the risc-v that linux runs on is quite a bit hairier to implement than the rv32i isa; you have to implement the risc-v privileged isa

— if what you're interested in is how varied cpu architectures can be —

probably risc-v and arm won't do it for you

the nand2tetris 'hack' is pretty weird, and very similar not only to the dirty genitals nova, but also to chuck thacker's 'tiny computer for teaching' https://www.cl.cam.ac.uk/teaching/1112/ECAD+Arch/files/Thack... which is two pages of vhdl

weird in a different direction is the tera mta, which has 128 hardware threads and context-switches every clock cycle; the 11¢ padauk pmc251 microcontroller does the same thing (but with only two threads; padauk sells parts with up to four threads)

the tera mta was designed to compete in the vector supercomputer field originally defined by the cray-1, which had a very different architecture; the convex https://news.ycombinator.com/item?id=40979684 was very similar to the cray-1

in a sense, though, the cray wasn't really the first supercomputer; the cdc 6600, also designed by seymour cray, was, and it was arguably the first risc, in 01964

unlike all of these, the burroughs 5500 architecture had no registers, just a stack, and that's what smalltalk, java, and c# are based on

the 12-bit pdp-8 was the first really mass-produced computer, with over 50000 units sold, and its architecture is interestingly different from all of these, too; intersil produced a 4000-gate single-chip version, and the family was popular enough that there are pdp-8 hobbyists even today

most current numerical computation is being done on gpus, and i don't know what to recommend as reading material on gpus, which have bizarrely different instruction set architectures that use a model called 'simt', single instruction, multiple thread. if anyone does, let me know

finally, chuck moore's line of two-stack processors based on forth are a sadly underdeveloped branch of the genealogical tree; koopman's stack computers: the new wave https://users.ece.cmu.edu/~koopman/stack_computers/index.htm... goes into their historical development a bit. they had some significant success in the 80s (the novix nc4000 and the harris rtx2000) but the later members of the family (the sh-boom, the mup21, the stillborn f21, the intellasys seaforth 40c18, and the greenarrays ga4 and ga144 chips) have no real users, in part due to malfeasance—after losing a protracted lawsuit with moore, intellasys head dan leckrone now goes by 'mac leckrone', perhaps as a result

there are lots of other interestingly different instruction set architectures out there: s/360, 6502, amd64, pic16, the erim cytocomputer, the thinking machines cm4, the em-4 dataflow machine, the maxim maxq, the as/400, webassembly, vulkan spir-v, the hp 9825 desk calculator, saturn (used in the hp 48gx), etc.

i hope this is helpful!

sillywalk4• 2 years ago

I'm not sure if it's quite what you're looking for, but Inside the Machine by Jon "Hannibal" Stokes of Ars Technica has a good overview of computer architecture in general, plus detailed looks at some different processors.

From the Introduction:

"Inside the Machine is an introduction to computers that is intended to fill the gap that exists between classic but more challenging introductions to computer architecture, like John L. Hennessy’s and David A. Patterson’s popular textbooks, and the growing mass of works that are simply too basic for motivated non-specialist readers. Readers with some experience using computers and with even the most minimal scripting or programming experience should finish Inside the Machine with a thorough and advanced understanding of the high-level organization of modern computers. Should they so choose, such readers would then be well equipped to tackle more advanced works like the aforementioned classics, either on their own or as part of formal curriculum."

lproven3• 2 years ago

they are historical books on computer design.
historical books
historical
orical
ical
cal
al

MUST. NOT. CRUMBLE. INTO. DUST.

mrgaro• 2 years ago

Thanks Master Ken for doing these awesome posts and participating in the Marc's youtube channel! Both amazing content!

throaway123452• 2 years ago

I really love these updates. I really appreciate your articles and they've made me go into a deep dive into the history of microchips and IC design in general.

How did you get into this in the first place? From your blog I gather that you used to be in software (or still are).

kens8• 2 years ago

How did I get into this? It started when I saw the simulation of the 6502 processor from the Visual6502 team [1]. It was very cool, but totally mysterious. I realized that even though I was a programmer and understood the "full stack", I had no idea how a processor chip actually worked. (I'd taken computer architecture courses but there's still a big jump to physical transistors on a chip.)

I started looking at the 6502's circuits and one thing led to another and here I am today, reverse-engineering obscure chips with a microscope :-)

[1] http://www.visual6502.org/JSSim/index.html

PaulHoule5• 2 years ago

I was lucky to get to use an IBM 3090 (close to the peak of the bipolar mainframe) with the Computer Explorers troop that met at New Hampshire Insurance.

We used VM/CMS where VM was a virtual machine monitor and CMS was a single-user OS that felt a lot like CP/M or MS-DOS. (I understand CP/M was inspired by CMS) If you have a lot of developers, they all get their own OS and normally they would store their files on "minidisc" images.

Even though the experience wouldn't seem too foreign to somebody who works on the command line today, the I/O was not character based but instead buffered the way the article describes. Applications were built around a model where you program fields on the terminal which get submitted when somebody hits the send button such as the XEDIT text editor

https://www.ibm.com/docs/en/zvm/7.3?topic=zvm-cms-file-edito...

which was functionally similar to the TECO editor you'd see on DEC minicomputers but quite different in implementation. (e.g. 1970's mainframe apps were similar to 1990's web form applications)

Since we had Digital right across the border in Massachusetts, schools and children's museums in my area where saturated with PDP-8, PDP-11 and VAX machines. The computer club (which met at the physics clasroom) at my high school inherited an old PDP-8 when the school got a VAX, it was an unusual system that they were planning to ship to a newspaper that didn't buy it in the end which had terminals that used an ordinary serial connection but could be programmed to behave like the 3270, we didn't have any software that used that feature until I got out the manuals and wrote a BASIC program that would send the control sequences for that mode.

anyfoo8• 2 years ago

If you want unfamiliar, try MVS on IBM s/370 mainframes. Version 3.8j (from the early 80s) is readily available, and runs great on the Hercules emulator: https://www.jaymoseley.com/hercules/installMVS/iMVSintroV8.h...

It made me realize just how many fundamental things that I completely took for granted in the "modern" computing world, were ultimately just concepts derived from UNIX (even for OSes that you'd think have little relation to it at all), and how there were (and in some capacity still are) very, very different worlds out there.

PaulHoule5• 2 years ago

In the 1980s a clear case of this was that MS-DOS 2.0 had system calls for file operations that basically worked like Unix whereas MS-DOS 1's filesystem API looked like CP/M.

It's an interesting story that IBM really struggled to develop an OS which was "universal" the way the "360" was supposed to be universal. The answer they came to was VM which would let you run different OSes for your batch jobs, interactive sessions, transaction managers, databases, etc. Contrast that to Unix, VAX/VMS or Windows NT where you can run all those things under one OS. In 1970 though, IBM had no idea how to do that.

Note today a Z installation is very likely to have Linux in the mix

https://www.ibm.com/z/linux

so it is no problem running your POSIX app together with traditional mainframe apps. Also there is a Java runtime

https://www.ibm.com/docs/en/zos-basic-skills?topic=zos-java

so you can host your Java apps.

kens8• 2 years ago

Yes, looking at IBM stuff is like being in a parallel universe where everything you take for granted is slightly off. You have token-ring instead of Ethernet, you have SNA (or something) instead of TCP/IP. Characters are EBCDIC, not ASCII. Terminals are connected with coax, not RS-232. For hardware, chips are packaged in metal instead of plastic. Circuit boards are a weird grid. Even the terminology and schematic symbols are different: if it looks like an AND gate, it's an OR gate.

rbanffy• 2 years ago

Easy way to do it:

    docker run -it --rm -p 3270:3270 rbanffy/vm370ce

This will set up a VM/370 Community Edition running on a beefy virtual 4381. Direct your 3270 terminal to port 3270 and check the README at https://github.com/rbanffy/vm370 for some bearings.

lproven3• 2 years ago

It made me realize just how many fundamental things that I completely took for granted in the "modern" computing world, were ultimately just concepts derived from UNIX

Oh so very much yes.

And the flipside of this is that it's very very hard to get new ideas into the heads of people who only know and have only ever seen computers running Unix-style or Unix-inspired computers.

Some examples:

The product that the inventors of Unix did next was Plan 9. It's still alive and in development. Some things that Plan 9 takes as givens that blow Unix folks' minds:

* There is no one true view of the filesystem. It's all namespaces and every process can (and normally would) see a different namespace. They are all correct and there is no one valid underlying view: it's all relative, and all interpreted.

* Everything really is a file. For example the contents of a window on screen is a file. Arguably if your GUI doesn't do this, is it really Unix-like?

* There's no keyboard-driven command-line editing because of course your computer has a graphical screen and you can just use the mouse. Why would you pretend your input window is a 1970s 80x25 text terminal? What's the point of that?

Then Plan 9 evolved into Inferno. It breaks more assumptions.

* C is not low level any more because computers have evolved very far away from the machines C was designed for. C has no native standard build-in way to represent matrices of 256-bit values and apply SIMD transformations to them as one operation, and no way to farm out 10000 threads to 1000 compute units.

So, throw C in the bin, and replace it with something a bit more abstract.

* Computers have different types of CPUs. So, compile source± to intermediate code and embed the runtime in the kernel. No need for a JVM or any other runtime; no need for WASM or eBPF; it's stock.

* Any binary can execute on any CPU. Computers can have more than one type of CPU and compiled code can move between them without translation.

Or to move further afield...

* The Unix tradition puts the filesystem at the centre of the design. Not all do. So some OS designs do not have filesystems and do not have the concept of files. It's objects all the way down.

* Some OSes and some languages don't have compilers or interpreters or binaries. That's a 1970s implementation detail and it was eliminated 50+ years ago.

This kind of stuff can be much more powerful than the Unix model, but folks reared on Unix dismiss these ideas as toys, not understanding that clinging to a 1970s idea built on computers which are less powerful than toys today is limiting them.

nsguy• 2 years ago

I've used a 3090 and some of the predecessors and VM/CMS. The "monitor" was called CP (control program) IIRC.

XEDIT was a great editor. There was also Rexx (and previously EXEC and EXEC/2) as the system's programming language that you could use to customize virtually every aspect of the editor and automated tasks. Rexx had integration with the editor and also integrated with the OS there were lots of these small integration points that let you do really powerful stuff. Applications like email were implemented on top of the basic OS and editor. A very unique and powerful architecture (mirrored to some degree in OS/2 later).

The ecosystem was incredible. The virtualization support in the CPU let you run a complete multi-user system with each user having a visualized CPU within one virtual CPU. I.e. it was "fully" virtualized. What's more incredible is that a lot of these pieces, like the OS, were all written in assembly. Super robust. Super clean. Amazing documentation for everything. As top notch engineering as it gets.

The full screen terminal (e.g. 327X) were part of the architecture, delegating a lot of the interaction to the terminal. Interesting enough you could poll the terminals for input which we've used for writing some games. A friend of mine wrote a library for doing that. There were also colour/graphics terminals like the 3279 and could be programmed e.g. with a library called GDDM.

EDIT: - https://en.wikipedia.org/wiki/VM_(operating_system)

Another interesting bit is that IBM shipped the full source code for everything (I think this was by default). They also had a shared bug reporting system (anyone remember what that was called?).

PaulHoule5• 2 years ago

Right. It was really common for sites in the 1970s to compile their own OS so they could set the configuration. This was how you told it which devices where attached on which ports.

ngcc_hk2• 2 years ago

I do not know you can do that as I think the 3270 block mode always did that. Might be CICS can do that but I wonder ... I only support block mode.

It would be interesting whether yo can release to six pack VM for us to try. We use 370 C to do gaming currently, ... does it allow this interaction I wonder.

travismcpeak• 2 years ago

This is really cool! How do you accomplish your research? I'm assuming IBM has some corporate records, but didn't realize they'd be this complete.

kens8• 2 years ago

We haven't been able to get old information from IBM; either they discarded it or don't make it available. There are lots of old manuals on bitsavers, which is a treasure for historical computer research. It is worrisome how much preservation depends on the efforts of a single person.

https://bitsavers.org/pdf/ibm/

anyfoo8• 2 years ago

One of my hobbies is writing period-correct stuff for s/370 and MVS, and, yep, bitsavers is where it's at. Weird thought that if that person didn't go through the effort, the information would be near-unobtainable.

epc• 2 years ago

This might be a bit morbid but consider contacting estate sales agents in the Poughkeepsie and Rochester areas? The last generation of hard core mainframe employees are all nearing retirement or have retired and as they and their families deal with the detritus of their careers may just be throwing away stuff. A lot of the print books ceased mid 1990s, in favor of BookManager files and eventually PDFs.

codedokode2• 2 years ago

Talking about chips, does anyone know what was the feature size in classical DIP-package chips like 4000, 7400, 74LS, 74HC, 74AC series? I googled around, but for example this Wikipedia article [1] has information only on CPUs, but not on simple logic chips.

[1] https://en.wikipedia.org/wiki/Transistor_count

kens8• 2 years ago

I looked at a random 7400-series die and I think the feature size is about 5 µm. (The width of the thinnest metal and silicon features.) Bipolar chips have different construction from a MOS processor, so the features aren't directly comparable, but this should give you a rough idea.

bregma• 2 years ago

I imagine a 7400 TTL quad NAND gate would have... 16 transistors?

codedokode2• 2 years ago

I was curious about feature size (e.g. wire width). The number of transistors can actually be found in some datasheets (don't remember exactly which manufacturer published it though).

kmeisthax• 2 years ago

Y'know, that thing about how IBM terminals are really form display machines instead of character streamers actually put something in context for me. Over a decade ago I interviewed at multiple companies whose business included adapting text-based interfaces for the Web. One was MUMPS[0], the other AS/400[1]. My thought was that they were writing shittons of text parsing code for each screen, but had I been hired and trained for the role I would have learned that HTML forms are poorly reimplemented IBM terminals and time is a flat circle.

[0] "AS/400, but it's a hacked-together line of business program turned hospital OS written when Microsoft Access was still in di-a-pers."

No, I don't know if MUMPS actually presents forms in terminal buffered I/O or not.

[1] "Microsoft Access, but it's an enterprise grade server OS written when Windows NT was still in di-a-pers."

axiolite2• 2 years ago

HTML forms are poorly reimplemented IBM terminals

In HTML forms you can SEE where the input fields are. You don't have to "PROTECT" the HTML document from warping. You don't have to hit a special key when an HTML document is larger than your screen.

And IBM manages to get credit for ALL the early computer technologies just because they're still around. Other block-oriented terminals certainly existed, and I'm glad they didn't catch-on...

akira2501• 2 years ago

you can SEE where the input fields are

There was always type="hidden" then they added CSS for extra spice.

You don't have to "PROTECT" the HTML document from warping.

Input elements have 'readonly' and 'disabled' and most other elements can have 'contenteditable'.

You don't have to hit a special key when an HTML document is larger than your screen.

Page Down?

jerrysievert• 2 years ago

you fully missed a bullet not working with MUMPS. my favorite "issue" when dealing with MUMPS was failure to run in production because a line wrapped into a second 4k "page".

that pretty much all medical records go through MUMPS scares the hell out of me after spending time moving broken web products off of MUMPS.

gumby• 2 years ago

You can run GNU MUMPS, written by Harlan Stenn who now maintains NTP

p_l• 2 years ago

Lots of MUMPS use in financial system these days.

bitwize• 2 years ago

The partnership between IBM and Motorola is something I find intriguing. And I'm not just talking about PowerPC. In the 80s -- long before Hercules -- IBM developed a "mainframe on a card" solution for use in IBM PCs. For a CPU, they commissioned Motorola to build a special 68000 CPU with different microcode that implemented a large subset of the System/370 instruction set. Any instructions that could not be implemented with this custom-schmustom architecture would trap, and be decoded and emulated by a regular 68000 that ran in tandem with the custom one. The resulting architecture was able to run mainframe operating systems and applications very well, providing mainframe developers a benchside testing solution that allowed them to run software still in development without tying up resources on the actual mainframe (which needed to have as much CPU time as possible committed to production workloads in order to be profitable to run).

Still probably cost an arm and a leg, though. The cards weren't sold on their own, but installed inside a PC under the names Personal Computer XT/370 or AT/370:

https://en.wikipedia.org/wiki/PC-based_IBM_mainframe-compati...

sillywalk4• 2 years ago

I remember reading about that, from the Chipletter in 2022[0]:

"The XT/370, with a hard drive, could be purchased for as little as $8085. This compares with a basic PC/XT with 256K RAM for $4395 and adds a lot more functionality."

...

"So what was the PC XT/370? Put simply, it was a PC XT (the original IBM PC with a hard disk drive) with three additional cards:

PC/370-P : A card with one modified 68000, one standard 68000 and lots of logic chips.

PC/370-M : A card with 512 kilobytes of memory.

PC/370 EM: Providing the ability to emulate an IBM 3270 terminal.

The XT/370 then became three machines in one:

An IBM PC/XT.

An IBM 3270 terminal that could be used to access a System/370 mainframe.

A machine capable of running some System/370 software."

[0] https://thechipletter.substack.com/p/motorola-intel-ibm-make...

segmondy• 2 years ago

"IBM's vintage mainframes were extremely underpowered compared to modern computers; a System/370 mainframe ran well under 1 million instructions per second, while a modern laptop executes billions of instructions per second. But these mainframes could support rooms full of users, while my 2017 laptop can barely handle one person"

Software has gotten complex, folks were running BBS with multiple users 30+ years ago on 286 computers. First multi user machine I used was 386 BSD supporting 50-100 students at once. 486 machines were supporting thousand of users at once. A cheap under $500 server can probably handle 5k hackernew users at once without missing a beat. Love the article, but don't blame the hardware, hardware has grown, software has just grown faster with so much waste as well.

DaoVeles2• 2 years ago

There are many factors that feed into the software complexity.

Added abstraction for ease of development, added demands of some software functions that are not so immediately apparent and the endless needs for ever higher security on software.

It is most points 1 and 3 that are the biggest issue. If we could code low level and didn't have to worry so much about folks trying to bust into various systems - the performance would be astounding.

mbreese• 2 years ago

I think the authors point was that even though the mainframe was underpowered from a raw performance point of view, it augmented that performance with accessory units and processors. By offloading as much of the non-core functions (I/O) as possible, the machines themselves would be able to process as much data as possible without waiting for input.

So while software has gotten more complex/bloated and hardware ludicrously fast, we still are waiting for input, IO, network, etc.

I think of it as the old school mainframe engineers knew every trick to eke out every ounce of performance. And they used all of the tricks. We’ve sadly lost a lot of those tricks because our hardware is so fast, we can ignore the performance losses.

DaoVeles2• 2 years ago

As an aside, I have seen some folks get incredible boot times simply by eliminating all devices wait times or loading things concurrently. Looking at game consoles is a good example of cold booting speeds but even they are much slower than even a decade or two back.

protocolture• 2 years ago

Uh thats sad. I processed one a similar IBM controller unit when I worked in recycling. I tried for 2 weeks to first figure out what the heck it was, and then secondly find a home for it that wasnt scrap.

Ultimately, it was gutted and converted into a mobile workstation.

Steve44• 2 years ago

Slightly off topic and not sure if this is allowed but I've a copy of MVS JCL by Doug Lowe and rather than dump it I'd be more than happy to send it free of charge to anyone in the UK.

It's in excellent condition other than a bit of staining on the outer rear cover

https://www.amazon.co.uk/MVS-JCL-370-XA-JES/dp/0911625852

I worked with them for a year or so at an insurance company and particularly liked some of the feature of the ISPF editor. You could hide rows then perform actions on the remaining columns, quirky but very handy when you needed it!

xxmarkuski• 2 years ago

I'm interested in toying around with IBMs current mainframe offerings and found news articles from 2022 about IBM offering mainframs in the cloud as an experiment. I setup an IBM cloud account and looked around at th offered services, but could not find services related to mainframes. Probably need to be a premium customer.

skissane7• 2 years ago

Anyone can easily get a quote from IBM Cloud for a hosted z/OS mainframe development system:

1. Go to https://cloud.ibm.com/vpc-ext/provision/vs

2. Make sure you select a Geography and Data Centre which supports z/OS. I know North America > Dallas > Dallas 2 does. Whereas Europe > Frankfurt > Frankfurt 2 doesn't. I haven't checked the others.

3. Scroll down to the "Image" section and select "Change image"

4. In the popup, you should see two button-like tabs. The default is "Intel x86s architecture", the other is "IBM Z, LinuxOne s390x architecture". Make sure you pick the s390x. If you don't see s390x as an option, it is probably not supported in your selected DC, go back to step (2) above

5. Select your desired z/OS version. Currently they offer z/OS 3.1 and z/OS 2.5. Let's just go with 3.1 – select the radio button.

6. Click "Save" at the bottom of the "Select Image" dialog

7. Now the screen will reclaculate, and you'll get a quote.

Mine is, US$1,874.76 a month before the "sustained usage discount". US$1,693.06 a month afterwards. That's with very minimal CPU/storage/memory/networking/etc, you might actually need to increase those numbers to get a usable environment.

And, if you are happy paying IBM US$20K+ a year, I imagine IBM will be happy to take your money. Some IBM sales rep will probably even be calling you trying to upsell.

sillywalk4• 2 years ago

IBM does offer the Z Development and Test Environment which is an emulated mainframe for a normal x86 computer. It's $5,980.00 / year. It looks like there is some sort of free trial, and there was a learner's edition.

https://www.ibm.com/products/z-development-test-environment

skissane7• 2 years ago

I've heard on the grapevine that IBM 3274 uses an IBM proprietary microcontroller architecture known as "universal controller" (UC) – https://bitsavers.org/pdf/ibm/microcontroller/universal_cont... – but not sure how true that actually is. In the absence of written documentation–which probably exists somewhere... but nobody has scanned it and posted it online–this stuff is often just people relying on their decades old memories, and sometimes things get garbled with time. Or some people may even have been confused to begin with.

Inside an IBM/Motorola mainframe controller chip from 1981

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