Fun things to do with your VM/370 CE machine – Fun with big computers (rbanffy.github.io)

77 pointsby rbanffy6 hours ago12 comments

jsrcout 2 hours ago

Thanks for this, can't wait to try it out. I discovered the Hercules emulator a while back, downloaded everything and fired it up, then discovered I had literally no idea how to do anything. It's just such a different world than the ones I'm familiar with.

AKSF_Ackermann 5 hours ago

Out of all mainframe OSes, VM is the most approachable imo, as long as you grasp minidisks and how s390 device addressing works, it becomes just a somewhat clunky DOS. I would also suggest checking out the 2.4 VM ADCD, it is a package with basically all the interesting software, and it is out there if you look for it.

rbanffy 5 hours ago

> a somewhat clunky DOS

And the Community Edition even has a handy DIR command for you.

This document has a lot of things left to add - the machines can really be a lot more interesting. So far, I haven't figured out how to connect my real printer over the network, the other machine with shared disks but no OS, and even creating a new VM for our user. I also know there are a lot of other interesting things on the base CE image that can be super cool to show a newcomer.

coolkil 3 hours ago

It is a very cool operating system. I had the pleasure of configuring it (in it’s ibm z/VM form) from scratch a few years ago. However due to company politics it only ran for 2 years. If you are based anywhere in the US you could probably make a career out of it. If you are in Europe I don’t know if it is a wise choice. Not much z/VM there. If you now own a modern mainframe and want to run Linux workload for example I think you are better of using kvm. However if you need to run z/OS virtualised your only option is still z/VM

rbanffy 29 minutes ago

I have recently played with a plain VM/370 R6 and it's very bare compared to CE - not even bold in the terminal to highlight your current line in EDIT. I was thinking of adding it to my collection of Docker images, but I need to play with tape images and, perhaps, load a bunch of them into the container image so there is something to do with it that resembles modern computing.

TomMasz 2 hours ago

It's been over 40 years since I had to type #CP IPL CMS PARM AUTOCR

Then engineering got a VAX and everything moved to VMS.

rbanffy 39 minutes ago

Yes. Everything is profoundly alien to anyone who's coming from a Unix background I was initially extremely confused. I was asking myself how does VM/370 define and starts VMs and thinking of a command line tool to do it.

JdeBP 4 hours ago

So much here:

Notice in EE the use of [F3] to exit as in the original CUA. As I said at https://news.ycombinator.com/item?id=50026580 .

Unix called it 'text' too. That's why the ETXTBUSY error's traditional message string is "Text file busy".

It's not losing the first character from FORMAT because of some magic line printer discard for the first character. It's losing the first character because you don't understand FORTRAN. FORMAT, as you can see in that example program, uses field descriptors to describe formats. It's losing the 'H' from 'HELLO' because that character means a 'Hollerith string' follows it, which in your case is the Mockney 'ELLO WORLD'. (-: You need an extra 'H', to start with.

In Unix terms, this is akin to the classic mistake of using printf() instead of puts() for your Hello program, and using a percent character in your string. In BASIC terms, this is PRINT USING, not PRINT. And yes, that does mean that technically you are holding it wrong. The text to write should be in the list given to WRITE, and FORMAT should just be specifying the field descriptor.

Only then do you get to the fact that the first column of formatted output specifies the number of printer lines to advance. So you are holding it doubly wrong. (-: There should be a space after the 'H' denoting your Hollerith string that precedes the 'H' of your 'Hello'. Notice that IBM's program has a space between the field descriptor "14H" (14 character Hollerith string) and "PROGRAM ERROR" (13 character string). That's not just random whitespace. It's the first character of the string, it means 1 line of vertical space, and the string is actually " PROGRAM ERROR".

You can get several native versions of REXX for Linux-based operating systems and the BSDs, including ObjectREXX and Regina.

* https://pkgsrc.se/lang/rexx-regina

* https://pkgsrc.se/lang/oorexx

* https://pkgsrc.se/lang/rexx-imc

It's 2026, and I just wrote about FORTRAN 66. Good heavens!

rbanffy 34 minutes ago

> It's 2026, and I just wrote about FORTRAN 66. Good heavens!

Thank you for the clarifications. I'll dig a little more and add that to the article. I learned Fortran 77 a long time ago, but I never used Fortran 66.

DonHopkins an hour ago

It it me, or does it feel totally different to be logged on instead of logged in?

Tepix 4 hours ago

So many ancient weird rituals to use this thing. We've come a long way.

coolkil 3 hours ago

Believe it or not this operating system is very much alive and kicking in the form of z/VM 7.5 and some of those ancient rituals are still considered normal in that world ;)