Teaching myself Z/OS assembler [closed]

Question

I’ve interned at a company that does a lot of mainframe work. Most of my mainframe experience has been using Java and Unix System Services. I’ve had some experience with the ISPF interface and C but none with assembler.

I’m graduating shortly and will be taking an independent study my last semester. I’d like to stick with the mainframe and was wondering what resources could teach me mainframe assembler.

Note that I don’t have experience writing assembler for any platform, but I do understand binary, hex, and have a theoretical understanding of registers.

Ribaldry

Answer 1

I've been able to teach myself the very basics using the following material along with co-workers who I can ask questions of. For an easy way to run and debug basic assembly programs I use the Z390 emulator with the option allowing use of the assist instructions as well as the test option for interactive debugging. I've used this as the main introductory tutorial. I've used this class site as another reference. Finally these Share materials may be useful although I don't know how good they are since they aren't very accessible with my screen reader.

Ribaldry

Answer 2

None of the following are tutorial-like, just reference material. All will eventually come in handy though, so good to know; of interest would be:

• HLASM Programmer's Guide
• HLASM Language Reference
• HLASM General Information
• MVS Program Management: User's Guide and Reference
• MVS Assembler Services Guide
• MVS Authorized Assembler Services Guide
• z/Architecture Principles of Operation

You can find the books for the z/OS version you're on at IBM doc library:

• http://www-03.ibm.com/systems/z/os/zos/bkserv/

z/Architecture Principles of Operation ("the POP manual") is the system bible. Of immediate interest in that book would be chapter 7 which lists the instructions and instruction formats.

For tutorial material though I can recommend (these are all on my bookshelf) any of the following:

• Mainframe Assembler Programming by Bill Qualls (this one comes with an emulator, PC/370, for compiling and running assembler)
• MVS Assembler Language by Kevin McQuillen and Anne Prince

And after you've mastered the basics:

• Advanced Assembler Language and MVS Interfaces For IBM Systems and Application Programmers by Carmine A. Cannatello

If you have questions you can, use stackoverflow of course, but for a more mainframe-centric pool of brains to pick, try http://ibmmainframeforum.com/. It isn't highly active, but the moderators know the dark arts.

Have fun!

Gittel

That pretty much duplicates what I was going to post. I work with IBM assembler almost every day, and it does get easier over time. I've not read the Qualls book, but I have the other two. Cannatello is a bit esoteric; you probably wont need much in there. McQ and Price, IMO, is horrible, but that could just be my particular style of learning. – Dispose

The Cannatello book may seem esoteric at first glance, but there really is some useful information in that book. I think the SVC99 for dynamic allocation chapter in the Cannatello book was worth the price alone. Not to mention the first four chapters are very introductory and useful even to the beginner. – Gittel

Answer 3

Learning assembler is certainly a good way of understanding how computers really work, but I'd suggest that jumping in to 390 assembler will involve a very steep learning curve. I'd suggest getting hold of a microprocessor emulator such as emu8086 which comes with a tutorial and starting with that. The basic cncepts you learn will be transferable to other ,more complex, architectures.

Incept

Answer 4

There is a mainframe emulator called Hercules, and some older mainframe operating systems can be obtained for free (legally). You may find that you can use this to do some experimentation with Mainframe assembler. The instruction set will be no more complex than a 386 family, so learning assembler on this system is probably as good as any.

As an alternative, this Stackoverflow posting discusses other ways to learn assembler.

Psychometrics

MVS 3.8j is the last legally usable of the z/OS lineage and it has about as much in common with z/OS 1.10 as Windows 2008 does with CP/M :-) But you're partly right about learning non-mainframe assembly first - it'll be easier and once it's done, it's a short step to switch over. – Archlute

Answer 5

I have been in your position; I am a student, myself. I have found that trying to teach yourself mainframe assembler, especially on top of other classes, with no support and no one to turn to for quick answers, it is best to just take an actual course in it. I have coded in C++, .NET, Assembler, COBOL, High Level Assembler and others, and the thing that really helped me in the two assembler classes was being in a structured environment with lots of support in place.

Sand

Answer 6

The Qualls book is available free for non-commercial use at http://www.billqualls.com/assembler/index.html. I admit to being somewhat biased towards the book.

Halinahalite

Answer 7

Posting on an ancient thread, but maybe it'll be useful to someone: Assembler Language Programming for IBM z System Servers 2.00 by the late great John Ehrman is a great resource. Also, a lot of useful info is on David Woolbright's website: http://csc.columbusstate.edu/woolbright/WOOLBRIG.htm

Jase