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Thursday, January 10, 2013

Technically right but practically wrong for the classroom

I've received some feedback on my multihead classroom computer post. I got a couple of messages which reminded me that X11 has been doing this sort of thing since the '80s, but they all seem to have missed the point. Yes, you can have X terminals which are basically a network interface to a screen and keyboard/mouse. So what?


Did anyone ever make an X terminal which would actually run multihead? Remember, the original problem was this elementary school computer lab had a bunch of kids crammed in there and hardly any room for these dumb little minitower boxes. Remember these things?

I've included a picture of the kind of hardware those schools had. That particular example (shown next to 3 nearly identical HP Vectras) was a bunch of parts from a local "screwdriver shop" built around a Pentium 120. That was "state of the art" for a classroom back then.

Did Intergraph or anyone else in the X terminal market actually make a box which would have been smaller than these things? Did these things take the standard 5 pin DIN or PS/2 keyboards? How about mice? Did they do the Microsoft style bus mouse, the serial mouse, or the PS/2 mouse? I'm not even bothering to ask about USB since that didn't come along until later.

I suspect the answer for all of those question is "no", and the reason is "they all used proprietary hardware". I'm talking about special monitors, keyboards, and mice. Remember those Sun mice with the special reflective little mouse pad thing, and how rotating it 90 degrees would make it not work any more? Yeah. That kind of stuff.

These schools had enough trouble coming up with enough money to get these dumb little boxes up and running. X terminals? Really?

Finally, to really rile up the Unix bigots, let me point out one last flaw in this plan: the kids (and teachers) wanted to run Kid Pix, Reader Rabbit, Number Crunchers, and lots of other stuff like that. Did any of those exist on any of the Unixes at the time? Somehow, I don't think they did.

This is one of those times when you can be technically right and yet be totally useless. Like it or not, the situation called for Windows. Sure, there were all kinds of horrible things which happened due to running so many fragile machines, but they treated all of that as secondary. They had clear requirements for the software which needed to be run, and anything which didn't satisfy that wasn't a valid option.

Finally, there was a visitor who suggested using monitors with built-in USB hubs who mentioned this reduced the problem to one of linking a display with its associated hub. They recommended using some kind of device which had a unique identifier which would also be plugged into the hub. A simple flash drive with a text file on it would suffice.

Unfortunately, I have to poke a hole in this one, too. Anything that can be removed from a computer will be removed from the computer. Sometimes, this is malicious. Other times, it's just bored little fingers looking for something to do because there's nothing else going on.

There's a reason optical mice were such a good thing for classrooms: they didn't have any balls. Back in the days when mice were just a couple of roller sensors sitting next to a relatively large ball which was tracked around by hand movement, they usually had doors underneath. This let you open it up to clean out the gunk which would accumulate. Anything on the user's hand tended to get on the mouse pad or other surface, and that would make it onto the roller ball, and that would make it up into the actual tracking mechanism.

This would cause the mouse to skip around and otherwise behave badly, so cleaning it out was kind of important. Of course, since it was trivial to open such a thing, and the balls themselves were kind of funny looking, is it much of a surprise that kids used to pull them out and then "lose" them?

I saw many dozens of mice which had been superglued shut or even "plastic welded" (melted) with a hot soldering gun to prevent such pilfering. Whoever did this basically wrote off any possibility of easily cleaning out the innards. They'd probably just let it get jammed and would then toss it out and replace it.

So, if you had some kind of little device just sitting there attached to a port, I'd expect it to (eventually) walk away. Just because it's out of sight of one kid doesn't mean it's out of sight of the one sitting on the other side of the table. Imagine a square table with a pole dropping down from the ceiling carrying power and network cables. The four machines back up to this pole. From any position, you can see the front of your machine, the side of two machines, and the rear of a fourth. It's not much of a stretch to see something small and interesting.

I'm really glad I don't have to support computer labs any more.