Wednesday, March 5, 2014

Dave Tuttle's Memoirs

Dave Tuttle's Memoirs

I suppose some people think they're in it just for the money or just for the tech or just for the business. Maybe. But human nature consistently shows us that we need something more. Ultimately, it's that "image of God" creativity, even for those who think we're not terribly creative (and those who know we're not terribly god-like or even godly).

Why do you do what you do?
In software, especially in FOSS, why do you code the code you code?


I attended a Git workshop this past Monday evening. (Yeah, yeah ... it's about time. Hey! It's not like I don't use code manglement, CVS, SVN, etc.) The class was taught by Aidan Feldman of github. Great stuff! Excellent quick workshop; got us all actually using Git on github. Anyway, he mentioned that Linus created Git. I asked if the legend was true ... that Linus did it over a weekend. The bastion of all human knowledge says Git was done in four days and fully operational in a matter of weeks. Ahhh... that's the good stuff.

Before Linus, there were other heroes: Vint and Vixie, Gettys and Garbee and Grace, Barber and Farber, John and John and Jonn (Eckert and Mauchly -vs- von Neumann, rivals), Brooks and Bartik, Kay and Cray, Englebart. I'm grasping at straws and leaving out dozens ... hundreds. But you get the idea.

Intrigue inspires and FOSS fosters freedom.


In my day job, I work with CMS. No, not that CMS, this CMS. It's IBM's "Conversational Monitor System" (fka "Cambridge Monitor System" to show some history). CMS is a single user, single-tasking operating system hosted by the oldest viable hypervisor: VM/CP the "Control Program".

Hey ... hypervisor ... you know what that is! It's that thing Rosenblum created. Yeah.

Not exactly. Didn't mean to drip into sarcasm. If I haven't lost the audience, then what follows may be more inspiration than irritation.

VM/CP is arguably the best hypervisor, and CMS (in spite of its warts) has been able to focus on a handful of incredible things, including CMS UPDATE. (We did mention code management, you recall.) I love this stuff!

Virtualization rocks! With CP under it, CMS is truly useful. XEDIT, REXX, Pipelines, a CISC processor and a full-featured assembler (plus C and other languages), that multi-level source code update tool, even OpenVM (yes, there's a shell, and yes, that part is multi-tasking).

History of VM

In the glory days of VM, Melinda Varian put together the often cited and repeatedly praised "VM and the VM Community: Past, Present, and Future". Her work ranks up there with Tracy Kidder's "The Soul of a New Machine", though less well known (and without the assist of a publisher).

I was already a fan of VM when I saw Melinda present at a SHARE conference. Hearing the history, the stories of how the system came to be, it all gave me chills. This is the system IBM tried to kill. Over and over.

The ultimate insult (to IBM) happened when Linux was ported to the mainframe. Linux works great on any platform, but is a teriffic candidate for virtualization, especially on high-redundancy hardware (like mainframes). There were two ports, by the way, one by IBM and another by Linas. No, not that Linus, and not that one either, this Linas. But that's a whole nutha story. (more intrigue!)

IBM sales guy: "Remember that system we told you to get rid of?"

IBM customer: "You mean VM? Sure. We got rid of it, like you told us."

IBM sales guy: "Well, you're gonna want it back."

IBM customer: [facepalm]


The 1991 revision of Melinda's paper had a couple of addendums. I picked up printed copies. [remember paper?] One addendum was "Dave Tuttle's Memoirs". This is not usually seen alongside the newer revisions (of Melinda's work).

At one job, we were hosting lotso Linux on top of z/VM. (That company had never gotten rid of VM anyway.) Trying to inspire my teammates, I made copies of Tuttle's Memoirs and passed them around. [remember printed copies?] Some of the guys actually read it. These were good guys. I don't think they were in it for the money, maybe for the tech. We weren't coding, but I hope they were intrigued.

Given the myriad search engines available, you can probably find Mr. Tuttle's work for yourself. Here's one I found (other than my paper copy), starting about page 135:

Enjoy! Be intrigued. Be inspired.

Someday I'd like to meet Dave Tuttle in person.

-- R; <><


  1. Hey Rick - the latest version of Melinda's paper is at Bonus: you get to see neat pictures and essays. Or use the direct link: regards, Jeff

  2. Yep. Saw that. Mentions some guy at Merrill Lynch and another at Rice U. It just doesn't have DT Memoirs is all.