Have your own personal mainframe
Monday, 18 July 2022
It was the year that I first started working on mainframes. Can you guess when it was? Leg warmers became fashionable. The first Happy meals were available from MacDonald’s. Walkmans became available from Sony. Trivial Pursuit became available. Pink Floyd released “The Wall”. Margaret Thatcher became prime minister in the UK. The USSR invaded Afghanistan.
Lots more happened, and the year was 1979.
The first mainframe I ever worked on had lots of flashing lights on it and it looked the way mainframes did in films and on TV. It was soon replaced by a 4341 model. Those were the days of removable DASD and lots of tape decks. We even had a paper tape reader and one user who sent stuff on paper tape to be input into the computer. And, yes, the paper tape did rip from time to time. Of course, there was also a card reader and a card punch. And lots of 11-inch multiline stationery going through the printers. And people would come along and collect their printouts.
It was such a different world.
The reason I’m taking you on this trip down memory lane is because, it seems, you can now recreate your own MVS Version 3.8 system. I think Version 3.8 came out in 1981.
If you go to https://wotho.ethz.ch/tk4-/, you can get hold of The MVS 3.8j Tur(n)key 4- System. The documentation tells us that MVS 3.8j Tur(n)key 4- ("TK4-") is a ready to use OS/VS2 MVS 3.8j system built specifically to run under the Hercules System/370, ESA/390, and z/Architecture Emulator. It is an extension of the original MVS Tur(n)key Version 3 System ("TK3") created by Volker Bandke in 2002. This version was written by Jürgen Winkelmann, between November 2013 and September 2016.
Now, someone calling themselves rattydave has created a Docker container containing a fully-running MVS 3.8j. You can find it here. Rattydave also has a fully-running Version 3.0 of IBM's Time Sharing System/370. You can find that here. Obviously, and fully credited, this Docker version uses the work of Bandke and Winkelmann.
The 'usage' section explains how to connect a 3270 terminal. It also describes how to add a full-function console when running in unattended mode. It uses a TN3270 emulator. The notes describe how to get basic TCP/IP support, and there are some useful getting started notes.
I just thought it would be quite interesting to know that you could use Docker, a very modern way of working on a mainframe to recreate a 3033 mainframe environment from the early 1980s. It seemed like a piece of coding fun that mainframers might well be interested in – particularly if they remember working on MS 3.8 back in the day.
It’s worth mentioning Hercules, which is an emulator that allows mainframe software to run on other computer hardware, eg PCs. It works with Linux, Windows, and even on Macs. It’s written mainly in C, and development started in 1999 by Roger Bowler.
Although it works with all mainframe operating systems, licences are required to run newer versions of mainframe operating system.
Interestingly, I’ve seen that it’s possible to run the software on a Raspberry Pi and recreate an old-time mainframe on one of the smallest computer platforms around.
IBM has its ZD&T Personal Edition, which lets a user run an IBM Z distribution on a PC running Ubuntu. The software can create an environment for mainframe application demonstration, development, testing, and education. It enables z/OS, middleware, and other z/OS software to run on Intel and other compatible computers. ZD&T Personal Edition emulates z/Architecture with virtual I/O and devices.
And, of course, you can now run mainframes in the cloud with IBM’s Wazi as a Service. The set-up is only available for development and testing, but it is another way of accessing mainframe systems from a completely different system and without an actual mainframe being involved.
I just thought it was interesting to see how mainframes could be emulated on other platforms, and how old ‘timey wimey’ (as Dr Who used to say) systems could be brought back to life.
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