Posts Tagged 'mainframe'

Mainframe Assembler Language 2.0

Those that still follow my blog from my days working in the IBM mainframe arena might be interested in the following.

One of the stalwarts of software at IBM, and self described grand poobar of High Level Assembler, John R. Ehrman has a 1300-page 2.0 version of his book “Assembler Language Programming for IBM System z™ Servers ” and it’s available in PDF form here. There are a wealth of other assembler resources that John has contributed here on ibm.com

The Open Mainframe Project

It would be remiss of me not to mention another new Linux Foundation project, the Open Mainframe project. I’m actually be pretty interested, from a purely personal perspective, to see what this project does and where they plan to take Linux on the mainframe.

I’m glad to see that both Linux on the mainframe, and the ecosystem is still thriving. Having been involved with it heavily back in the late 90’s, and writing essentially the only public strategy in the original and republished IBM Redbook “Linux for S/390”. The first four chapters were mine.

I can recall with great fondness discussing with them head of IBM Systems Group, and future IBM CEO, Sam Palmisano and many others, the real reason Linux would be key to future success, it’s freedom. With India and China coming on stream as technology powerhouses, with millions of future programmers, it was clear that they would learn on Linux.

Even Windows was still the most pervasive operating system in 1998-2000, it was clear from anyone who understood technical people that Linux would influence not jut code, but threading, languages, library structures, call interfaces and more at the system level. For no other reason than people can study the source, learn from it, adapt it etc. and that was a train IBM couldn’t stop, we needed to be on board before the train left without us. There is a good NY Times article from the period here.

Good luck to the Open Mainframe project.

Federal Reserve and Mainframes

Over on the Mainframe Executive blog, there is an open letter to the US Federal Reserve Bank, questioning the Fed’s apparent desire to move or switch their systems away from mainframes to distributed systems. Well you would expect less from the Mainframe Executive blog. I have a different take on why the Fed should not only keep their mainframe, but why they might want to move more work to it.

I worked on many of the early mainframe Internet applications. I did the high level design and oversaw the implementation of an Internet Banking Solution that the bank, Sun Microsystems and Microsoft had all failed to get to scale. Our design went from 3k users to I believe at the end of 2-years in production, close to 990k users without an upgrade, and without a system outage. It was built off two mainframe systems outside the firewall, running as a Sysplex. I also did a design review for a bank that had lost close to $60k from four accounts, the back end on the mainframe the mid-tiers and Internet servers distributed.

The point of this post though isn’t to gloat about my success, isn’t being a ‘mainframe bigot’ or even saying the Fed should use the mainframe. In the Mainframe Executive they raise the usual specter of security, yes security is a big deal for banks, even more so for the Fed. So yes, make a big deal of it.

However, the single most important thing to understand about building trusted computing systems, isn’t that you provide a 100% secure environment, in which applications aka business transactions, run. It is that you can show who did what, when, and how. Auditing is much more important than security. If you believe you have a 100% secure system and you lose some money but can’t audit it, what do you do, shrug your shoulders and say “oh well never mind”?

Auditing isn’t about just seeing that you have procedures in place. It is the ability to pick apart a debit transaction on a system that was executed at 4:05pm along with 30,000 others, show how that transaction was invoked, where from, under what security context, what ID, and the originating network address and more. That might require looging through logs of 7-10 distributed systems.

If like the bank I did the design review for, you can’t show the correlation of events leading up to the execution of the transaction, and you don’t know for certain where the user eneterd the network, what ID they used, and how that security context was passed from one system to another, then you don’t have security, no matter what they say.

When you are looking after the nation’s money, and despite the obvious current finicial position of the US, budgets not withstanding, I’d say that was pretty important. What does the Fed say?

I say “Show me the audit, show me the audit, show me the audit…” (repeat ad infinitum)


About & Contact

I'm Mark Cathcart, formally a Senior Distinguished Engineer, in Dells Software Group; before that Director of Systems Engineering in the Enterprise Solutions Group at Dell. Prior to that, I was IBM Distinguished Engineer and member of the IBM Academy of Technology. I'm an information technology optimist.


I was a member of the Linux Foundation Core Infrastructure Initiative Steering committee. Read more about it here.

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