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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 community has been supportive and offered their insights and corrections in the past - so I feel this will work just fine!

The topics I have planned are:
  1. Updating a Mainframe [Looking at firmware updates, EC streams, etc.]
  2. How does a Mainframe boot? [Looking at the IPL process]
  3. Defining I/O devices [What is IOCDS ? + Looking at HCM]
  4. Fejkon: PCIe and DMA [Talking a bit about what a PCIe device is, and why this thing called DMA is needed]
Hopefully it will be an interesting series!

As always, thanks for reading


  1. Can't wait ;-) .... I'm youre Fan!

  2. Hi!

    I'm new to the Z platform, and I'm eyeing this z114 system:

    Can you give me a very rough idea of a budget beyond the purchase price to get it up and running would be?


  3. Hi! I am eyeing this z114 system: fa=Main.Item&itemid=174&acctid=17125

    if I can convince my other half to dedicate the space to it.

    Can you give me some sort of an idea of what budget would I be looking at, beyond the purchase price, for ancillary equipment, software, etc?

    1. Hi! Very nice haul there. I guess you are looking at running only one of the 3(!!) z114?
      In general the most expensive part is the running cost, a single z114 is about 2 kW running power (does not matter much if it is idle or not). Running one of those storage arrays in that auction would be really nice for your setup, but those can be *much* more power hungry than the mainframe itself.

      You definitely want a z114 with DASD (ECKD) if you want to run things as "they should". While you can pick up cheap SCSI SANs not all mainframe tools can run under SCSI so you would be handicaping yourself.

      In terms of budget - if you win that auction I think you have everything you need in terms of initial purchase, save a network switch and possibly a storage switch (in total $1000 tops for both). Then some SFP modules and cables, maybe $500 tops for those.

      Good luck! You can reach out to me at chri***an@cmd _dot_ nu if you want.


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