Wikipedia:Reference desk/Archives/Computing/2017 December 17

= December 17 =

IBM z/OS and other mainframe operating system
I was looking at this YouTube video to see what IBM z/OS is like, because there's no chance I'm ever going to afford a zEnterprise system of my own.

What immediately struck me is how weird-looking the interface is. It's nothing like any operating system I have ever used, which include AmigaOS, MS-DOS, Windows and Unix (Linux and Sun Solaris). Is this really what z/OS looks like? Or is it some programming environment inside it?

How does one even use z/OS? How does one run programs, access files or access the network? J I P &#124; Talk 10:06, 17 December 2017 (UTC)


 * Don't dismiss your dream, be more positive, this youngster bought his own IBM mainframe -) This Teenage IBM Employee Got His Job By Buying An Old Mainframe Computer. If you're too frightened by that idea you could start small with the The Hercules System/370, ESA/390, and z/Architecture Emulator. And yes, that is what it is like. Dmcq (talk) 10:30, 17 December 2017 (UTC)


 * I see that that guy managed to buy an IBM z890 for less than one-thousandth of its original price. Still, he had to have his parents help him transport it to their basement, and even getting it to boot up was difficult. I think that is way too difficult and too much work for me. I'm using a used HP Z420 professional workstation as my personal desktop, and I'm perfectly happy with that. I'm reading IBM's own "Introduction to the new mainframe: z/OS basics" guide as a PDF, and am finding it all very difficult. The only operating systems I have ever used are those I mentioned earlier: AmigaOS, MS-DOS, Windows and Unix, which are all file-based and command line -based, rather than this weird record-based and menu-based z/OS. I downloaded and installed Hercules, but I couldn't even get it to start without copy-pasting an example  configuration file, which I didn't understand anything about. And even that only got me as far as Hercules' own command line, it didn't even boot any operating system up. I guess trying to learn mainframe operating systems is too difficult to be worth my time.  J I P  &#124; Talk 23:49, 17 December 2017 (UTC)
 * You do have to be a bit of an enthusiast to run emulators for systems like that, well for any emulators. As for running one's own mainframe like that person - that's just amazing. Those systems started up originally in the 1960's and have just changed slowly since then as the companies running them want consistency and don't like sudden changes. They do run a version of Linux as well and that is much more approachable. Dmcq (talk) 00:55, 18 December 2017 (UTC)
 * Pedantry alert: "record-based" is not the antonym of "file-based". A record-oriented filesystem is one way of handling files (and the way IBM and most mainframes have always done it); the other is byte-oriented, as on Unix, where files are just treated as bags of bytes. Note also that z/OS itself isn't really "menu-based". z/OS doesn't care how you talk to it. ISPF is what's menu-based, and using it is optional, though common. Menu-based console programs like Midnight Commander are used on other platforms. (And then there's emacs, which is practically an operating system on its own.) --47.157.122.192 (talk) 10:08, 18 December 2017 (UTC)
 * The video depicts the use of ISPF. Most of the video is the user working inside ISPF, editing a COBOL program and the JCL commands for executing it. You run programs, access files, and access the network the same way you do on any computer with an operating system: by using the operating system's facilities for doing so. ISPF and TSO aren't wildly different from command-line interfaces on other platforms. z/OS is fully POSIX-compliant, so you can even run a Unix shell on a z/OS system. The Art of Unix Programming has a chapter that contrasts Unix with other OSes, also giving a brief overview of each's design: here's the section on MVS (the core of z/OS and earlier IBM mainframe OSes). --47.157.122.192 (talk) 10:08, 18 December 2017 (UTC)


 * JES2 comes with zOS for free. Operators use SDSF to start programs (I've never used it). Larger shops pay extra to use JES3. Operators can start started tasks or they can submit jobs from ISPF. Sleigh (talk) 09:50, 18 December 2017 (UTC)


 * Those are incantations in an arcane language to a great an powerful mainframe. There are some mages of immense power who understand their meaning and consequences, but mostly hand me down and patched versions of the commands are gabbled uncomprehendingly by its attendants. :) Dmcq (talk) 12:10, 19 December 2017 (UTC)