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Comment by rbanffy | Hacker News Reader

Fair warning: this is not an introduction.

If anyone is looking for an introduction to the modern version of the platform, this free e-book from IBM is great: http://www.redbooks.ibm.com/abstracts/sg246366.html?Open

I'm trying to get my Multiprise 3000 up and running. Is there something like this for S/390?

Search that Redbooks site for 'abcs of systems programming'. There's a 5-volume set from 2000 that covers S/390 and OS/390.

Also check out the OS/390 ADCD Redbook:

https://www.redbooks.ibm.com/redbooks/pdfs/sg246204.pdf

Which I found pretty helpful for finding my way around. (I see from the cover that it includes MP3000 info!)

Edit: Have you seen this? (I think this guy hangs out on HN)

ftp://ps-2.kev009.com/incoming/timc/PDFS/IBM/S370%20&%20S390/MultiPrise%203000

He does. He's been a great help as I try to piece together enough stuff to function as a system element. And thank you for that redbook link; I have a load of stuff, but somehow missed that one. Thanks!

Can Hercules run MP3000?

The MP3000 (Multiprise 3000) is the smallest mainframe IBM ever made, weighing in at only about 300 lbs. Using the vanilla Hercules, it can be MIPS limited to act mostly like a MP3000 System/390 machine and run the same OSes.

To me, it's a realistic introduction it's just that as computers became ubiquitous, marketing them as easy to use was the dominant strategy. It's been very successful. People will shop weeks on faith in silver bullets to avoid four hours RTFM'ing.

It's certainly a gentler introduction than the current, 2,000-page z/Arch Principles!

And along similar lines, it's kind of fun, if not at all useful in any economically rational sense of the term, to write nontrivial source- and binary-compatible code that builds and runs on everything from a 40-year-old 370 to a current-model Z (speaking hypothetically, as I don't actually have access to even a reasonable facsimile of the latter; I have, however, tested as far forward as late-model OS/390 running in 64-bit z/Arch mode on emulated hardware).

It's a typical programmer's hardware manual for the period.

More or less until the IBM PC, it was normal for computer vendors to supply a detailed bit-level breakdown of instructions, memory operation, data formats, interrupt structure, and so on.

Although similar information was of course also available for the IBM PC even if it wasn't as routinely used. An assembly language reference for a PC contains much of the same information as a POO for a mainframe or mini.

Things were different in the early days. In the 1970's I worked at a company that had an IBM S/370 and a clone, an Itel AS/5.

IBM supplied hardware schematics and microcode listings for their S/370 hardware. They were in the machine room and freely available for perusal by us.

In a bit of irony, they also supplied schematics and microcode for the Itel clone. That's because the Itel was a true clone. It was designed by copying IBM's circuitry, but implemented in Motorola 10K series ECL instead of IBM's proprietary technology.

You read that right. In order to debug a problem with the Itel, the Itel field service engineers used IBM's schematics.

I think a lot of this free availability was because IBM was facing antitrust pressure from the US government. I don't know all the details.

Here's more history about the clone: http://www.silogic.com/NAS/NAS.html

It is compared to the rest of their documentation. 360s would come with a bookshelf of binders going down to the circuit level.

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