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Streaming setting up the mainframe

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 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:

Recent posts

Powering a mainframe

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 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!

Now, everybody wanted to see if it was working. My machine did not come with a power cable so I had to so…

Exploring and Repairing an DS6800

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The intention is for this post to be updated as new information becomes apparent or outdated.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.

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

FICON HBAs: The mysterious Bus-tech

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 commo…

Brocade Fabric OS downloads

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:…

Unboxing accessories and DS6800 troubles

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 system1x Virtual Tape Engine (VTE)1x Access Control Point (ACP)2x Brocade 5100 SAN switch1x 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 server itself (2U + 1U) and …

Mainframe project news

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.

The next issue was that the datacenter told me they discovered the mainframe would not fit the elevator they had to take for the spot they had planned for. They are still processing alternatives, but I am not too wo…