VT100's

[Paul Koning]

> On Sep 7, 2018, at 8:46 AM, Noel Chiappa via cctalk <cctalk at classiccmp.org> wrote:
> 
>> From: Paul Koning
> 
>> inside are a whole pile of boards, all single-sided etch with many
>> hundreds of jumpers to compensate for not being two-sided. Not cheap,
>> presumably
> 
> If memory serves, didn't the VT52 also have single-sided boards with a whole
> bunch of jumper wires? Something relatively common, anyway, if not the VT52 -
> I clearly remember the masses of jumpers on something, and Tech Sq had scads
> of VT52's (to the point where VT100's were not that common when they did show
> up, we were already full up).
> 
> Presumably, with automated placing machines, the jumpers were cheaper than a
> large double-sided board (the VT52's boards were huge)? I'm assuming _someone_
> did the math (including the amortization of the placing machine, which would
> take longer to complete such a board).

I don't remember the VT52 board, but you may well be right.  The obvious advantage of single sided boards is that it avoids plated through holes.  I once did a two-sided board without plated through holes (at the U of Illinois -- the board shop didn't know how) but that wasn't reasonable technology for serious work because you have to solder both sides then.

The VT61/t stood out to me because it has so much stuff in it.  I forgot how many boards, but it was way more than the VT52 (which has just one, I think).  No surprise, the VT61/t has local editing / forms processing capability with block mode transmission both ways.  In one Typeset-11 application you'd edit a screen full of text locally and send it back when done; in the other you'd fill in a classified ad order form and send that.  The VT71 also had local text editing but there it's a whole file, with local scrolling and search, line wrap, and macros ("User Defined Keys", UDK, tied to a row of blank keycaps that the customer would label).

	paul