Me so geeky - Jay Maynard

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Thursday, 20 January 2005


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2032 - Me so geeky

In the general cleanup of the machine room, we found a place for an IBM terminal controller and terminal. Of course, I just had to get it running again - as a regular VT220.

The IBM 3270 series of terminals and terminal controllers was designed to work much differently from the average computer terminal. Instead of sending characters one at a time when a key is pressed, and displaying them one at a time as received from the host, it was designed to present a form to the user, which he fills in and transmits to the host in one big glob. This was done to minimize the demands on the host computer, thus making things more efficient.

In later days, IBM realized that it might be a Good Thing if its terminals could be used with host computers from other manufacturers. They added the ability to do that, although it was a bit clunky. Even later, they added networking abilities to the controllers.

I have a 3174-61R controller with a Token Ring interface. (That was $500, complete. If I'd gotten one with an Ethernet interface instead, it would have been $3500.) I've also got a nice 3472 infoWindow terminal to go with it, as well as a couple of 3270 terminal cards for my former employer's product. I've also got a Token Ring adapter in one of my Linux systems.

I had to rebuild the kernel in Red Hat Enterprise Linux version 3 because they didn't include the TMS380 Token Ring adapter module as standard. I also had to tell that system to forward the packets and do address masquerading, so the 3174 appeared as though it was on my main LAN. With that done, I was able to log into the main Linux server here:

Logging on from the 3270

and run the mutt email client:

mutt on the 3270

and the slrn Usenet news reader:

slrn on the 3270

Needless to say, these look very strange to an old-time mainframe geek like me. That's why I had to do it.

current mood: [mood icon] geeky

(10 comments | Leave a comment)

Comments:


[User Picture]
From:ckd
Date: - 0000
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Bah, the only real 3270s are the big honking metal ones, the ones that can crush a small car with ease and have keyboards that weigh more than a modern laptop. 3278s forever! (especially the APL ones)

Seriously, though, yes that's pretty darn geeky. Congrats!
[User Picture]
From:jmaynard
Date: - 0000
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3278s? Wimp. Grab yourself a real 3277 if you want to crush a car. The 3278 keyboard is positively flimsy compared to a 3277's.

I've been wondering: You do know, of course, the special significance the initials CKD have in the IBM world, don't you?
[User Picture]
From:ckd
Date: - 0000
(Link)
I know of the reference, but never used any count-key-data stuff myself. The 3090 that was the main undergrad computing machine back in my day was running a particularly bizarro homebrew OS on top of VM.
[User Picture]
From:jmaynard
Date: - 0000
(Link)
Was it MUSIC, or MTS, or something completely homebrew?
[User Picture]
From:ckd
Date: - 0000
(Link)
Completely homebrew.

Let me put it this way. You have a machine running VM, which lets you have really solid walls between different virtual machines. Do you:

(a) set up the OS so that users have their own virtual machines (the CMS approach), or
(b) write an OS that runs everyone in the same VM?

Your compilers expect upper-case input. Do you:

(a) expect users to enter upper-case text, or
(b) case-flip all input and output, so they type in lower case, it's flipped to upper case, compiled, output is generated, and then that's case-flipped before display or printing?

It was rumored that the university licensed it to UWaterloo in exchange for a Waterloo SCRIPT license, and that it was an exceedingly bad deal for UWat to have done so.
[User Picture]
From:jmaynard
Date: - 0000
(Link)
I can see putting lots of users in one virtual machine. That does, after all, save on system resources. In the days you're talking about, that's a nontrivial consideration. That also lets you terach things like how to write a scheduler.

As for the compiler, though, that one's just brain-dead. I can see folding case on input - if the language isn't case-sensitive (and I consider case sensitivity a major botch, and the single worst feature of C and Unix), then it shouldn't matter what case the user uses, and the output should be in whatever case (or mix thereof) the user gave as input.

Which school was this? ...and the OS historian in me wonders if it'd be possible to lay hands on this OS, no matter how horrible it may be, as worthy of preservation - if only as a bad example.
[User Picture]
From:ckd
Date: - 0000
(Link)
Boston University. It was called VPS (or VM/VPS) and Google hits mostly get Hummingbird's ftp client, which had support for its ftp server (presumably because BU had a site license or something back in the day).
[User Picture]
From:sideband
Date: - 0000
(Link)
Wow.. You Are Geek. Hear You Interface!

Lucky..

The most "classic" piece of equipment I have is a (FUNCTIONAL!) DECstation 5000/200.

Back to the drawing board. I now have to out geek the ubergeek. ::sigh::
[User Picture]
From:jmaynard
Date: - 0000
(Link)
I've got a 5000/240. I used to use it as an IRC server with NetBSD. I've also got a 5000/25 that was the development system for that one, so I could build stuff without jeopardizing the IRC server's reliability.
From:jono181
Date: - 0000

Chey, what's up?

(Link)
Jay,

All of your computer gear should be on a rack or steel cage of some sort. Much safer. I do recommend getting a rackmount for all of your gear.

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