Selected Tek Storage Tube Terminals

	Tek's first storage tube terminal had a
	611 display with a separate one line refreshed editing area.
	It was a learning experience for Tektronix IDD.
	The original design had alphameric and point plot.
	Slow point plotting with remote computers over phone lines prompted the
	addition of a vector generator.
	Vectors were drawn with a simple R-C network.
	The writing beam was pulse width modulated for short vectors to prevent
	overwriting or CRT burns.
	The complicated logic required to support the local editing functions
	locked up all too easily.
	The logic was spread among a large number of small boards.
	These were connected by an expensive custom 10 or 12 layer backplane.
	The T4002 accepted a plug-in ("aux box") in the rear.
	One such plug-in provided graphic input with a joystick.
	The 96 character 7x9 character generator ROM usded discrete diodes
	on many small boards.  The character generator skipped over dark pixels
	to increase speed.
	Stan Davis designed a nice analog bell circuit.

4802	Serial interface.  Speed controlled by R-C oscillator.

T4002A	Various logic cleanups. The character generator used ROMs which were
	not available when the T4002 was designed.

4014 Demo Video     Most easily viewed with Chrome or IE. Firefox takes some fiddling.

Tek 4014 Storage Tube Terminal Plot Files and Vplot Software (Linux)

Plots converted to GIF (The original plot files are in plt.tgz)

It was the early 70's. Men walked on the Moon. Good looking stewies worked for the airlines. July 1971 brought the Second Annual Conference on Computers in Undergraduate Instruction to Dartmouth University. I was project engineer for the Tektronix 4010 storage tube graphics terminal.

Bob Perterson and I flew out to Dartmouth to introduce the 4010. The Tek travel department booked engineers economy class, but we flew First Class because economy was full. The drinks were free and so were the stewies. We had a great time in United's Friendly Skies. The abrupt transition from high altitude carousing to the O'Hare concourse was a bit of a shock. I was still at 29,000 feet.

We showed some A-phase terminals at the conference. Users suggested product changes, some of which which I incorporated into the 4010.

The A-Phase 4010 high voltage power supplies arced over in the hot and humid New England summer. We could barely keep one or two 4010s working with continual emergency care packages from Portland.

		Selected Tek Storage Tube Terminals

4010	First model in the 401x series. The logic was in a pedestal.
	The 4010 benefited from lessons learned from the T4002 program.
	The 4010 was designed for low cost, a fraction of the T4002.
	Moderately large logic boards plugged into a simple backplane.
	The 4010 "Minibus" had minimal addressing (CSTROBE/TSTROBE)
	and time domain arbitration with the CPUNT signal.
	The base model 4010 had TC1, TC2, and an interface board.
	The character generator used a commercial 5x7 64 character ROM.
	The character generator used unlit pixels above the characters
	to allow the deflection to stabilize its slew and wrote dots on the fly.
	Character writing speed was about half that of the T4002A.
	Graphic input was standard with a pair of crossed thumbwheels..
	Constant 2.6 ms vectors were drawn with 2nd order R-C active filter.
	There was no compensation for short vectors.
	The logic was greatly simplified and could not be locked up.
	A 4.9152 MHz crystal provided timing for serial interfaces,
	character generation, vector drawing, graphic input, even the bell.
	I was project engineer and there was NO BLOODY FAN.

4010-1	A -1 indicated hard copy readout circuitry

4012	A better yoke supported 7x9 upper and lower case characters. 
	A prototype analog fast vector board shortened the time constant
	for short vectors and the end of long vectors.

4013	4012 with ASCII/APL keyboard and character generator

4014	19 inch storage tube using a TV glass envelope.
	Four character sizes available up to 133 x 64 lines.
	4096x3072 12 bit addressing, write-thru and defocus modes.
	Hardware dotted/dashed digital vectors designed by Dick Preiss.
	Large linear power supply but NO FAN.  Still civilized.

4015	4014 with ASCII/APL

4016	25 inch storage tube with noisy fan.  Logic same as 4014

4006	Designed after I left Tek. The bare essentials of the 4010.
	No backspace.  No graphic input.  LSI chip used for serial I/O.
	(Correctly working LSI chips for serial I/O were not availble previously.)
	The logic was based on a sketch I made years previously of a single board
	4010 subset to advocate reducing the difference in selling price between
	the 4010 terminal and 613 monitor.

4081	Workstation powered by an Interdata 7/16 minicomputer.
	We wanted to use our own CPU but weren't allowed to.
	Upper management insisted this was to be some sort of Uberterminal.
	We wanted to build a workstation.  The only successful app was
	as a workstation (so I'm told).

Basic serial interface provided speeds from 150 to 9600 bits per second.
It was implemented in discrete logic because the then available serial
converter chips were so buggy a large amount of TTL was needed to fix the bugs.

Buffered serial interface - 64 deep FIFO on receive, could be modified
to drop ClearToSend when terminal busy.  Can be modified to operate at 38k.

Audio Recorder Interface - Recorded and played sessions at 4800 or 9600 bps.
At 9600 the ARI worked well with Sony cassette recorders and metal tapes.
Used for demoing terminals when a computer was unavailable.  Could also
be used for file backup when nothing else was available.

I developed a PDP-11 parallel interface for the 4010 series at Tektronix.
This emulated the standard DEC TTY serial interface. Its use with Unix was
problematic due to the high per character interrupt processing overhead.
This overhead was insignificant at 110 bps, but brought Unix to a near
standstill driving the 4014 in graphics.  The solution was to write a
small program using the Unix phys(2) call to access the hardware directly.

I kludged a parallel interface for Linux using the Centronics parallel
port.  See phys.c for details.

TTY Port interface - Dick Preiss designed a higher speed interface that
provided the serial clock signal to the host.  The clock could be stopped
when the 401x was busy to prevent overruns.

An interface driven by an Intel 4004 was developed.
An optional board for the 401x terminals provided Special Point Plot. SPP allowed the write time to be set for each point, providing a "green scale". The board could also drive a mechanical plotter.

We had a few raster scan images made with the University of Maryland Flying Spot Scanner which was used to digitize nuclear decay traces. A "catalog poster" containing thumbnails of posters available for sale was digitized. The picture of Raquel Welch from a movie poster was popular in "green scale".

The 2splot program included in the vplot package uses ImageMagick to convert a variety of popular picture formats (GIF, BMP, JPEG, etc) to green scale special pointplot files. 2splot can use dithering instead of greenscale if special point plot is not available. Some pictures convert better than others. Special point files tend to be large, requiring a parallel interface to provide a reasonable viewing experience.