Operating the KC8-EA Programmer’s Console


This is a short tutorial for operating a bare PDP-8/E without any system software using the KC8-EA Programmer’s Console. The console is used to toggle in the RIM loader (a basic loader program for paper tapes). Then the RIM loader is used to load the BIN loader (a more sophisticated paper tape loader) from a paper tape. Then the BIN loader is used to load the demo program from a paper tape into the core memory of the PDP-8/E. Finally, the demo program will be executed.

This demonstrates the typical bootstrap process of a small PDP-8/E system without mass storage (disks or DECtapes).

  1. Run the PDP-8/E Simulator. You only need the ASR 33 Console Teletype and the KC8-EA Programmer”s Console windows. To get information about operating the KC8-EA Console, read the KC8-EA Programmer”s Console Help (from the Help menu) and use the help tags in the KC8-EA window. Reset the simulator (using “Reset” from the Simulator menu).
  2. Toggle in the RIM loader:
    Go to the KC8-EA Console, set the Switch Register (SR) to 7756 (a switch down is a binary zero, switch up is a binary one) and depress the Load Address key (LOAD ADDR). Note that the Memory Address display now shows this address, the start address of the RIM loader. Set the Indicator Selector switch to MD. Set SR to 6032 (KCC) and operate the Deposit key (DEP). Note that the MD display now shows the value deposit in memory and the Memory Address display is incremented by one enabling you to load the next value into the next memory location. In the same manner, setting SR to the desired value, then operating the DEP key, toggle in successively the following opcodes of the RIM loader:
    07756  6032  KCC        / ALREADY TOGGLED IN
    07757  6031  KSF
    07760  5357  JMP .-1
    07761  6036  KRB
    07762  7106  CLL RTL
    07763  7006  RTL
    07764  7510  SPA
    07765  5357  JMP 7757
    07766  7006  RTL
    07767  6031  KSF
    07770  5367  JMP .-1
    07771  6034  KRS
    07772  7420  SNL
    07773  3776  DCA I 7776
    07774  3376  DCA 7776
    07775  5356  JMP 7756
    07776  0000  AND 0
    07777  5301  JMP 7701
    
  3. Now check if you have toggled in the RIM loader correctly:
    Set SR to 7756 and press LOAD ADDR. Press the Examine key (EXAM). Is MD now 6032? Repeatedly press the EXAM and check if the MD display shows the next opcode of the RIM loader. Note that the Memory Address display shows the next address and not the address of the value shown in the MD display. When you find a wrong value, set SR to the address of the wrong value, press LOAD ADDR, set SR to the correct opcode and press DEP. Then repeat the RIM loader check.
  4. Load the BIN loader from paper tape:
    Go to the ASR 33 Console Teletype and load the file “BIN Loader.rim&rdquo (included in the simulator distribution) into the reader of the teletype and turn the reader on. Go to the KC8-EA Console, set SR to 7756 and press LOAD ADDR. Press the Clear key (CLEAR) and then the Continue key (CONT) to start the PDP-8. The BIN loader tape is read in. When the progress bar in the teletype window disappears, press the Halt switch (HALT). Operate HALT again to return it to its upper position.
  5. Load the demo program “rotate.bin” using the BIN loader:
    Go to the ASR 33 Console Teletype and load the file “rotate.bn” into the reader of the teletype and turn the reader on. Go to the KC8-EA Console, set SR to 7777 (start address of the BIN loader) and press LOAD ADDR. Press CLEAR, then CONT. The paper tape is read in until the PDP-8 halts. Now turn off the reader and unload the paper tape.
  6. Run the rotate demo program:
    Set SR to 0200, press LOAD ADDR, then CLEAR and CONT. The program runs. Set the Indicator Selector switch to AC, then watch AC and modify the Switch Register. For the sort feature of the program, go to the ASR 33 Console and type some 4-digit positiv octal numbers, then the $ key. Your numbers become printed in sorted order. For further information about the rotate demo program, read the comment and source code of the rotate program.