Skip to main content


Showing posts from May, 2019

Why have mainframes as a hobby?

My earlier blog article named Buying an IBM mainframe  did get way more exposure than I could have hoped for, thanks to everyone that read it! The discussions on various forums did naturally evoke some interesting questions. Mostly they are "Why?" in various shapes or forms. It is a totally understandable reaction, and thus I want to present some of the things that I am excited about having mainframes as a hobby. I present to you: the follow up questions on the statement "I bought an IBM mainframe". Why? I thought mainframes were dead First of all, they are not. If you are buying a new mainframe today you will get a beast in terms of performance and especially I/O capability. There is no server platform that compare to my knowledge in pure numbers if you do not include cost. Of course, you would care deeply about cost in any real-life situation but the point is to dispel the notion that mainframes are antiquated technology wise. Even my 8 year old z114 can

System z on contemporary zLinux

IBM System z supports a handful of operating systems; z/VM, z/VSE, z/OS, z/TPF, and finally zLinux. All the earlier mentioned OSes are proprietary except for zLinux which is simply Linux with a fancy z in the name. zLinux is the term used to describe a Linux distribution compiled for S390 (31 bit) or S390X (64 bit). As we are talking about modern mainframes I will not be discussing S390, only S390X. There is a comfortable amount of distributions that support S390X - more or less all of the popular distributions do. In this  list  we find distributions like Debian, Ubuntu, Gentoo, Fedora, and RHEL. Noticeably Arch is missing but then again they only have an official port for x86-64. This is great - this means that we could download the latest Ubuntu, boot the DVD, and be up and running in no time, right? Well, sadly no. The devil is, as always, in the details. When compiling high level code like C/C++/Go the compiler needs to select an instruction set to use for the compiled binar

Buying an IBM Mainframe

I bought an IBM mainframe for personal use. I am doing this for learning and figuring out how it works. If you are curious about what goes into this process, I hope this post will interest you. I am not the first one by far to do something like this. There are some people on the internet that I know have their own personal mainframes, and I have drawn inspiration from each and every one of them. You should follow them if you are interested in these things: @connorkrukosky @sebastian_wind @faultywarrior @kevinbowling1 This post is about buying an IBM z114 mainframe (picture 1) but should translate well to any of the IBM mainframes from z9 to z14. Picture 1: An IBM z114 mainframe in all its glory Source: IBM What to expect of the process Buying a mainframe takes time. I never spent so much time on a purchase before. In fact - I purchased my first apartment with probably less planning and research. Compared to buying an apartment you have no guard rails. You are left