Transistor Logic Module/Board based Computer
author Neil Franklin, last modification 2012.05.09

computer based on logic containing individual transistors and resistor/diode
technology standard of roughly early-mid 1960s DEC logic modules

either RTL or DTL or TTL or TTL-S or TTL-LS style circuits
  preferably not RTL, as so it is possible to do standard amp + diode logic
  preferably also not TTL or later, because lots of parts for speed
  extreme case miniature vacuum tubes als "DTL" diode tube logic

logic modules all same size, somewhere 14 (12sig+2pow) .. 20 (18sig+2pow) pin
  minimal 14pin and set of functions 6inv|4nand2|3nand3|2nand5|1nand11
    possibly multifunctional board 1..4|6 amps, (11/)5/4/3/2/1 diodes/amp
  maximal 20pin (8+8+2*2)pin diode grid for NANDs (not 16in NOT-NAND-NAND PAL!)
  frame with rows of module sockets, logic devices on modules
    for sockets normal standard edge connectors, direct from boards into them
      alternatively use hole-raster boards with angled IDC connectors, no PCBs
  logic is wire-wripped onto frame, requires no logic dependant board layout
  each row set of power/ground wires, on same pin of each module
    all ground wires on entire frame connected, power always separate
      in middle of each row an low voltage AC power converter/stabliser module
    down this middle column of power modules 2 strong AC lines
      separate transformer at bottom of each frame, pure AC out, nothing else
alternative design split diode-AND-logic and R-R/T-NOT-amplifier functions
  14/20pin only 2*[6|9]pins to 6|9 pure NOT amplifier stages
    or even less or larger boards
  logic in AND diodes as part of frame wiring
  same frame format, rows of amplifier modules, and power for them
alternative just standard raster boards, develop standard logic parts layout
  go for superlarge boards with VG64 connectors, basically handwired PLAs
  rows of R-R/T NOT amplifiers, and between them rows of diode AND logic
  then wire them on back of board, more logic per board, less larger boards
    saves connectors and does universal multifunction logic board, HP9100-like
  and for each amp n possible AND-diodes from neighbor/further(segments)
    wiring scheme similar to programmable wide-AND + fixed NOT-cell FPGA
  logic in arrangement of AND-diodes+segment-jumpers on boards
  then frame simple backplane board, linear wiring, bus, not logic dependant
    additionally short distance jumper connectors between boards, PDP-8/E-like

single frame enough for PDP-8 plus memory and IO controllers
  possibly even for an simple 16bit RISC system, or even an PDP-11
    but there quite likely separate frame just for memory
small 4004-like system even on less space
  even 8008/8080/8051-like will fit in single frame
due to size most likely an 12bit/PDP-8, or if large an PDP-11
  or more likely an 16bit RISC system of own design (or T212)
  or even copy an 8bit microprocessor-like design, possibly subset+extended

ROMs one diode per bit, row decoder and then n bits sections each col mux
  density using small diodes such as 1N4148 is at 1bit/2.54mm^2
    so 4kx12bit would be 3x4 * 64x64 * 2.54x2.54mm = ca 3x4*6x6in = ca 18x24in
    simple 4kbit (64char*6x6pixel, = 384sextet) character ROM is 4.5x4.5in
  if system with mass storage then just minimal boot-ROM PDP-8/E-like
  alternative rope memory 8*8=64 wires, 1s looping through, 4..16 rows
    or better make this systematic with printed foil, traces cut for data
  alternative HP 9100-like inductive 2-layer board ROM, or capacitive 2-layer
    but unlikely to do this, as HP took years to get it work
  if standard backplane and small connectors
    from 1st connector address, split for row decode and col mux
    from 2nd connector data output, from processor to memory
    to 3rd connector data input, from memory to processor

RAM proper would be cores, but cores not available any more, so other design
SRAM-style structure possible with transistor+resistors, 1bit/[8x2]*2.54mm^2
  so 16x4bit ist already 32x32 * 2.54x2.54mm = 82x82mm, 1/2 160x100mm eurocard
DRAM-style structure possible with transistor+capacitor, 1bit/[3x2]*2.54mm^2
  so 1kx12bit is already 3x4 * 32x32 * 2*2.54x3*2.54mm = 6x12*32 /10in^2
    even 256x8 is 4x2 * 16x16 * 2*2.54x3*2.54mm = 128x96 /10in^2
alternatively try to get cores, from old core planes, desintegrate
  re-weave own memory in the fitting size, but lot of work
    so if hand-made RAM possibly just simple 8bit toy system
      8instr+32byte-mem, or 8instr+indir+16byte-field+256byte-mem (like EDUC-8)
  also all the details of working out currents ant timing, and asjusting
    not possible without an oscilloscope for testing
alternatively as no real fitting memory possible, do non-original
  cheat with "modern" 6116 (=2k), 6264 (=8k), 62256 (=32k) SRAMs
    same also ROM cheat with 2764 (=2k) EPROM or 28C256 EEPROM or 29Fxxx Flash
    in this case data bus on one connector, address and control from 2nd
  this would be neccessary to run an PDP-11 or 16bit RISC with an decent OS
    in particular if memory managment and 1MByte RAM wanted for these
  but this would als destroy the entire 1960s tech demo effekt
    could no longer show any more that computer without chips are possible

special IO connector modules (if modules) or adaptors (if multifunction board)
  with the special connectors and any analog parts needed to drive them
  stage amplifiers, any DACs or ADCs, when at end of card on bus standard logic
memory connectors just large amount of signals, module edge connector as plug
video HD15 or cinch mult digital input for white/black/sholder/syncpeak level
  or alternative go for oscilloscpe X/Y mode with Z output, fits historically
    go for positioning by 6..8bit DACs, (64..256)x(64..256) grid
    make 3x5+1 Font in 4x8 grid, with 16x8 or even 32x16 charakters
      gives 64x64 or 128x128 grid, depending on what can still do 15or20Frame/s
    or go for 6x12 Font, 6x8 displayable as band, 20x10 or 40x20 charakters
      gives 120x120 or 240x240, of an 128x128 or 256x256 full grid
  or even just go for 8..32char 7-seg, 14-seg or 5x3-matrix LED output
keyboard PS/2 resistors, or direct level just wide digital out/in (like C64)
  in later case full TTY layout or just octal or hex "frontpannel" keypad
all other IO with normal Out registers and In DTL opencollectors