PDP-11/20, was Re: ebay question

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Thu Feb 26 18:02:19 2004

> Remember that the 11/20 came out in 1971. I'm not sure LEDs even
> existed that long ago, and they certainly weren't common as lamp

My HP9810 calculator has LED displays and a row of 5mm LEDs along the top
of the keyboard for status indication (program/run mode, etc). Dunno the
exact date, but it's around 1972 I think.

My HP9830 even has 5*7 dot matrix LED displays in it.

But LEDs were certainly not cheap back then!

> Digging... the schematics in the pdp11 directory at www.bitsavers.org
> support this: the 11/45 console schematics show lamps, the 11/70

My 11/45 certainly has lamps.

-tony
Received on Thu Feb 26 2004 - 18:02:19 GMT