Selected Tek Storage Tube Terminals T4002 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.
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 ten 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 up to 9600 bps. Used for demoing terminals when a computer was unavailable. Could also be used for primitive file backup. 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.