All of the threads here where right on target, and should serve you well if you follow them as prescribed. I have found that there is no definitive source on the architecture. It is really a vast landscape , I actually read the hardware manual supplied with the 3031 CPU's,, they had a lot of instruction detail,, what a geek I was.
To recap.. Mainframes don't actually have a backplane that's governed by a bus arbitrator scheme as some implementation have done in the past. That channel subsystem as it was called, was strictly a place for the more experienced coders so beware. It has it's own methodology when it came to writing code.The channel subsystem is really a processor in it's own right. All throughout the architecture you'll find various processors that are part of the machine architectural composition, but IBM does not disclose their origins....ie. OS/2 was used as a loader at one time. HMC's are now INTEL based..etc.. To actually program at the assembler level is fairly easy, debugging is where the nightmare starts. I/O on z/OS is straightforward, I/O on VSE is a little tricky. I/O on VM was a no brainier even though the manuals were almost indecipherable at times. V/M did provide the optimal learning environment since you could at one time run both DOS/MVS like macros. You interactively execute a program without much fear of harm, but you still had have some minimal knowledge of what was actually being performed on your behalf. IMHO the best place to start is by tracking down some of the old 360/370 textbooks. Many (all) are out of print.. But you can try OPAMP technical books in Los Angeles. Occasionally I'll see a book by Ivan ( make that Dr Ivan) Flores, Harry Katzan et al. These were good text books. There were some early books on microprogramming that did some in depth examination of the instruction sets from various Mainframe Manufacturers. You can try locating them, but this might be a little too over the top also. I find that the ABC's books are filled with good and useful information, but even they can be a little too over whelming at times. My two bits to learning. KISS, beg , borrow , steal , share good code. Make sure you have a "GREEN" card handy, THE POP is your friend, Macro instruction documentation are essential to getting past the bumps, and there will be many. If you ever run across those old blue XA manuals on macro coding grab'em they're golden, and you can still gleam a few tidbits from'em. Learn XDC or TSO test. Be humble,, there always a darn good assembler programmer hanging around who tell you a thing or two. I'm 25 years in and the guy sitting next to me is 50 years in. I'm humbled Good luck and keep following the thread. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
