mainframe.dev

Given that the last post on this blog was a bit more than 2 years ago it should not come as a surprise to anyone; I feel like I have sufficiently scratched the mainframe itch and have moved on to other projects. I have spent the last few months getting all my mainframe equipment into the hands of the next-generation of hobbyists and since a week or so I am now officially sans mainframe. This also means it feels a bit silly to operate a blog or an internet persona around supposedly doing things with mainframes, when I do not own one or participate in projects around them.  Enjoy some parting images from the move.         Image 1: Getting a mainframe down a ramp requires a lot of friends          Image 2: Mainframe loaded and ready to move to its new home I have been thinking about possible other names to rebrand my shenanigans but nothing concrete yet. The current blog will remain here hosted on Blogger.com, for how long I guess time wil...

Yesterday after more than a year's delay my zBC12 mainframe finally booted up. This is a machine that was donated to me in hopes to advance the hobbyist community, which I am eternally grateful for. Image 1: Athena, the zBC12 that just now got online Then what is the main selling point of the zBC12 versus the z114? You might recall my article  System z on contemporary zLinux  where I explained that running modern Linux on a z114 is hard. This is the main selling point for me to upgrade - being able to run things like more modern Linuxes than z114. While the latest OSes in zLinux, z/VM, and z/OS require z13 or newer - a zBC12 still allows me to run a few releases newer software. Image 2: The operator himself in the picture with Athena Perhaps one of the bigger deals that is very welcome is the support for OSA-Express5S. This means that while previously you needed both PCIe and I/O bays in order to have both effective higher speed connectivity like 8G FC or 10 GB Ethernet as wel...

 In this post I want to dig deeper into a phenomenon that I spent a few day debugging with friends. It will be a story of a behavior that seems illogical at first glance, broken even, but will seem feasible in the end. Let's begin! Things you will need: The scenario requires one host and one switch minimum*. In our example we will use two Linux hosts, an Arista DCS-7050S switch, and an Arista DCS-7050QX switch. The second switch and host is not strictly needed, but it makes the scenario more realistic and is how we found this issue. The story begins with you and a couple of friends are building an internet exchange (IX) for education and for fun. The simplest IX is just a simple switch - yes even an unmanaged thing you can pick up for $10 would work theoretically. The switch has one purpose: connect different actors together so they can route traffic between each other. See diagram 1. Diagram 1: Your typical IX network. It's just a switch. You have your IX switch and...

I have done systems administration for as long as I remember, and while I have set up countless of services and servers - I have quite limited experience working with the full life-cycle of truly enterprise software. Therefor, I thought it would be interesting to understand more on how one would plan for and execute updates on an IBM Z Series mainframe.

I have to make a post mentioning the last couple of months, anything else would just be weird I feel. I hope you all are doing as well as can be in these unpredictable times. I know I have been personally affected by this pandemic in multiple ways yet I feel fortunate - things could have been so much worse.  While I am one of the lucky people who work in a job that lends itself reasonably well to work from home, it took some time to get used to which had me focus more time and effort on things like home improvements and new daily routines to help me adjust to this new way of living. Thankfully I was not alone in this journey and I am thankful to all my friends, family, and of course my partner for being there for me. We all need to take care of each other. The last couple of weeks I have resumed my work on mainframe related projects and I have a series of blog posts that I wish to publish coming up. Some of these topics are going to be deep-waters territory for me, but the communit...

Wow, time flies. In the past months I've been working on a handful of projects related to the mainframe, but nothing that is really finished - so I thought I would summarize some work I've been doing instead.

The latest project I've been working on is a custom card that will allow me to interface any mainframe using the FICON protocol. I have a lot of ideas on how this could help a lot of hobbyists out there, and possibly folks doing development for mainframes as well. For my own purposes, it would allow me to not be reliant on my (still broken) DS6800 array. DE5-Net card running fejkon

The last couple of weeks I've been traveling for work, and I spent a long flight reading some publications I had saved up about mainframe and Fibre Channel. I will talk about some good sources of information later, but for now know that FICON runs over Fibre Channel, and indeed a lot of the reasons behind why Fibre Channel is known to be really reliable is that it more or less came out of IBMs requirements for accessing mainframe disk storage. Enterprise disk storage has this annoying issue that the disk arrays are: Heavy Power-hungry Ridiculously expensive An example: DS6800 is widely known to be an unreliable platform, and I would certainly never run a mainframe on it based on my experiences repairing mine. However it is as small as disk arrays get, but it is still 50 kg empty, and consumes 500W of power! However the DS6800 is kind of a black sheep in reliability. What if we look at something bigger and better? The big brother DS8000 is known to be rock solid fo...

A couple of weeks ago we streamed installing the mainframe in the datacenter from scratch. When we arrived the only thing that was there was the mainframe itself, some power cables, a fiber drop for Internet, and some shelves. Nothing was connected together. Being a datacenter it is of course noisy from all the fans, so I am not surprised that streaming with sound did not work out. Never-the-less it seems like at least some folks enjoyed the stream. Given that the stream content is somewhere around 12 hours, I figured a written walk-through of what we connected and why is in order. This is it. The main connections you will need to your mainframe are: Power Fibre Channel (FICON and/or FCP) Ethernet Fiber Ethernet Copper (Management) Power Power has already been covered in the Powering the mainframe article with the notable update that connecting both power cables for some reason trips the fuse in the datacenter. The manual says this: Depending on the server configurat...

I want to try something I have never done before. I will stream setting up the mainframe. Ok, let's try this. Stream for setting up the mainframe is going to be at twitch.tv/mainframedev . I aim to start tomorrow (Sat) at 13:00 CEST / 11:00 Z. It's going to be recorded as well. Tune in and chat with me and my friend soundgoof when we install a mainframe from scratch. — Christian Svensson (@blueCmd) August 9, 2019 As I mentioned it will be recorded and I will post the uploaded videos here after the fact unless something catastrophic happens. Update: The stream was successful! You can watch the recording here:

The last few days have been eventful. I was contacted by the datacenter that the mainframe's cage is now ready for moving in, and the power has been made available. Very exciting! I grabbed my home-made power cables (more on that later) and my best screwdrivers and set off to the datacenter. The view next to the datacenter The datacenter staff, not needing a forklift in their day-to-day, had managed to solicit the services of a forklift, the associated operator, and some very handy folks to help navigate the mainframe from the storage space to its final location. After some intense period of fighting the inclination of the road between the storage facility and the cage (and a door that was a bit too small) it was finally in place. Incidentally we were forced to trust the wheels on this pretty rough floor. I did not expect it to roll that well on raw concrete, I was pleasantly surprised. This thing is a tank! Finally in place! Now, everybody wanted to see if it ...

This is an knowledge base of various information about the IBM DS6800 that I hope will be useful if you ever need to repair one of these disk arrays. The intention is for this post to be updated as new information becomes apparent or outdated. Right now the post is very much in a pre-alpha state and I hope to have more of a narrative down the road, but I thought it would be fun to share the story as it develops. The DS6800 controller, our patient Note: The post has been moved to its own site to allow for other interested parties to contribute. Turns out there are quite a number of people that want to help :-). Continue reading at https://ds6800.mainframe.dev .

Commonly when talking about Fibre Channel the assumption is that you are talking about attaching some sort of storage device to some resource that wants to use that storage. However, Fibre Channel itself does not care about the storage part. Fibre Channel only facilitates opening a channel between two devices, which is referred to as nodes in Fibre Channel lingo - then what you do after that is up to you. Most commonly you will use a protocol called FCP (protocol 0x08), which confusingly stands for Fibre Channel Protocol, which is the protocol responsible to moving SCSI commands over Fibre Channel. Another relatively new protocol is FC-NVMe (protocol 0x28) which is for, wll, NVMe over Fibre Channel without going through any SCSI layers. Another one is FICON which uses protocol 0x1B or 0x1C depending if the frame is from or to a control unit. A host bus adapter (HBA) is a device that enables a computer to access a network, more or less always some sort of storage network and most com...

Fabric OS is what runs on the SAN switches I will be using for the mainframe. It has a bit of annoying upgrade path as the guldmyr blog can attest to. TL;DR is that you need to do minor upgrades (6.3 -> 6.4 -> 7.0 -> ... > 7.4) which requires you to get all  Fabric OS images for those versions. Not always easy. So, let's make it a bit easier. Hopefully this will not end up with the links being taken down, but at least it helped somebody I hope. These downloads worked for me and are hash-verified when I could find a hash to verify against. Use at your own risk etc. The URLs are: ftp://ftp.hp.com/pub/softlib/software13/COL59674/co-168954-1/v7.3.2a.zip ftp://ftp.hp.com/pub/softlib/software13/COL59674/co-157071-1/v7.2.1g.zip ftp://ftp.hp.com/pub/softlib/software13/COL59674/co-150357-1/v7.1.2b.zip ftp://ftp.hp.com/pub/softlib/software12/COL38684/co-133135-1/v7.0.2e.zip ftp://ftp.hp.com/pub/softlib/software13/COL22074/co-155018-1/v6.4.3h.zip ftp://ftp.hp.c...

I am back in Switzerland. It has been a good two months away from work, and the first morning after coming back I rushed to the office to unpack and inspect the goods that will hopefully make the mainframe come alive. So far the equipment is: DLm2000 virtual tape system 1x Virtual Tape Engine (VTE) 1x Access Control Point (ACP) 2x Brocade 5100 SAN switch 1x Arista DCS 7050S-64-R 10/40 Gbps switch I am also eagerly awaiting 2x Brocade 7800 SAN switch which should help me connect with other mainframers in the world and share some storage with them. The Arista and the Brocade 5100 were really no surprises, booted up fine and had decently recent firmware. No worries there, so I'll skip the details. DLm2000 The DLm2000 is a component I am excited about and I think has great hack potential. It is more or less 2x FICON PCIe cards, and 1x 10 Gbit/s card. It presents itself as one or multiple tape drives and stores the drives as AWS tape files. Given the size of the...

This is going to be a short update to share some good developments in the project. First of all: the mainframe has cleared customs and has been received by the datacenter. Customs caused a bit of a headache as eBay lists the sale price as the "Buy it now" price even if an agreement was put in place. This is usually fine as they values do not diverge a lot but in this case it was $300,000 vs $12,000 which would mean a significant difference in taxes to be paid. Thankfully the customs department listened to my arguments and they agreed that the accepted offer is what I should be taxed on. I must say that I am very pleased in the help UPS provided me with here, I assumed all logistics companies had gone sour but UPS redeemed themselves in my eyes with this delivery. Mainframe being unloaded in the Swiss Alps at datacenterlight . Photo by Ungleich. The next issue was that the datacenter told me they discovered the mainframe would not fit the elevator they had to take for...

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...