Talk:Tektronix 4014
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[edit] A lot of PoV, now removed
Grg99 added all of this text to the article; I've now removed it to here. There's some good data here, but it's wrapped in a lot of PoV and some of it certainly needs references. Feel free to adapt it back into the article, but please be encylopaedic about it.
Atlant 16:04, 6 July 2006 (UTC)
The 40xx series started out with the 4010, which was much like the 4014, except no write-thru mode. In write-thru mode, the terminal could write some light lines without having them stored on the screen.
The 40xx series was one of Tek's early use of digital IC's and had several annoying hardware glitches:
(1) The terminal had no input buffer, so if you erased the screen, incoming characters would be lost, as the screen erase took a considerable fraction of a second.
(2) There were some curious design choices. The "beep" on Control-G was a very digitally controlled 256 cycles of audio-- extreme overkill. However the serial port had a very shaky analog clock, so shaky that if you adjusted it to 1200 baud when it was first turned on, after an hour or two of warming up, the clock would have drifted several percent, enough to cause data transmission glitches. Very annoying.
(3) There was a bus where you could plug-in expansion cards, but the bus was poorly designed-- there was no bus arbitration, so the keyboard or cursor controls or plug-in cards would all step over each other's data. The only reason the bus worked at all was that the keyboard data was only presented for a few microseconds, and that rarely stepped on incoming data at 120 baud.
(4) The screen was rather fragile-- if you left an image on the screen for a long time it would tend to "burn-in" and leave an afterimage for many days. Sometimes the afterimage remained forever, and the only cure was a replacement CRT, about $2000 !!. The manual mentioned that the screen was only good for about 20,000 writes and erases, so each displayed page cost about ten cents!
(5) The original 4010 had UPPER CASE ONLY output. There was no good reason for this limitation, as a lower-case chip was only $7 more. It did allow them to sell an upgraded 40xx model for many more $, just to add lower case.
(6) There was no error-correction protocol on the data line, so the typical modem glitches of that era resulted in really wacko lines being drawn.
(7) The display was very very dim on the early models. You couldnt really use it in a mormally-lit room. Typically you'd have to turn off all the room lights to use this terminal.
An amazing device, and very flashy in its time, but nobody would tolerate all its limitations today.
[edit] Photos
I've still got a working 4014 in my office. I'll put up a bad photo now, and try to get a better photo to put up later, although who knows when I'll get to it. Rees11 22:30, 17 January 2007 (UTC)
