rolffson.de
rolffson's 1401 datacenter 3D simulation
documentation
last update 2020-12-01, 2021-01-18 minor corrections
chapters:
1401 commands
1401 front panel
user interface
1403 printer
026 card punch
card drawers
trash bin
1402 card reader/punch
729 tape drive
reel stands
main menu
known issues
⌂ home
1401
List of currently supported commands of current version 0.1.9.
New commands will be added step by step.
remark:
- sign handling for multiplication ("@") only tested for positive arguments.
- core memory up to address 999 (decoding above 999 not ready)
- check (parity) bit currently more or less cosmetic
ERRATA for this list: 'compare' (C) implemented and tested

1401 panel
- sense switches working, may be checked via command BxxxB..G, switch up = branch
- last-card switch A, last card may be checked via BxxxA, switch up =
sense
- START button: action depends on MODE switch
- STOP button stops execution
- before runing/stepping a program, set I-Reg and press check_reset and
start_reset
- CHECK RESET button resets error status
- START RESET button resets OP cycle
- to start at a certain address, set MODE to ALTER, press I ADD REG to select
I-Adr register,
enter address via manual address knobs, press START to load address,
then set mode to RUN again.
Don't forget to hit check-rest/start-reset before hitting run.
- no tape load
lower case characters on printouts or punch cards represent special characters:
g - group mark
q - lozenge ('sQuare', lower case L too similar to number one)
1401 mode switch:
- click on left or right side of switch to rotate one step
- currently functional modes are ...
- storage printout: print memory excerpt (group mark prints 'g',
where original 1403 prints space)
- character display: show memory at address
- alter: change register or memory
- run: start program at current I-address
- single cycle process: step through instruction fetch (I-cycles)
and execution (E-cycles)
1401 address switches:
- click on left or right side of switch to rotate one step
- can be used for: alter adress register + alter memory + character display +
storage print out
- address_stop + single_cycle_non_process not yet
working
1401 aux panel:
- bit switches and ENTER switch can be used to enter data into core when MODE
set to ALTER
- check stop / disk write non functional
interface
"game"
interface:
- use WASD to move
- use right mouse button to rotate view or to look up / down
- use mouse wheel for zoom in/out
- use ALT mouse wheel or RMB wheel to crouch / tiptoe
- use left mouse button to click
- cross hair mouse cursor: clickable, but possibly too far away to click
- hand mouse cursor: clickable
- green markers on floor for quick travel / rotate
1403 printer
1403 printer:
- click on paper in printer top to zoom to printout
- click again on paper in printer to close zoomed view
- currently only one page w/o scrolling
- START key works
- paper stack moving, but no printout visible directly in printer; click on paper to show text
026 punch
- when standing near 026, click to focus
- click card bed in the middle to focus in or out even further for better reading
- to leave the device, click Quit button on
device
-
possibly not all characters supported
- currently only blank cards from feed, no
pre-punched
- no backspace
- no program mode with program card
- press CTRL-F to feed new card and register other cards
- press CTRL-R to register cards without drawing new card
- press CTRL-L to reLease
- to eject all cards, press CTRL-R and
CTRL-L alternatingly
- click left card stack to take cards into hand, if hand empty
- SHIFT click: take stack and put behind cards already on hand
- CTRL click: take stack and put in front of cards already on hand
- to remove released card in left bed before stacking, click upper left notch
- to remove unwanted cards or change sequence,
take the cards to the drawers
card drawers:
- when standing near drawer, click to focus
- drawer can hold three stacks
- cards can be scrolled through:
- W / S moves between last card of front stack and first card of
middle stack
- E / D moves between last card of middle stack and front card of
back stack
- R / F does W+E / S+D simultaneously
- SHIFT + scroll key moves 10 cards at once
- ALT left click: put stack on hand to middle stack in drawer
- left click: take stack into hand, if hand empty
- SHIFT click: take stack and put behind cards already on hand
- CTRL click: take stack and put in front of cards already on hand
- to leave the drawer, type <TAB>, or click Quit
- when other drawer nearby visible when focused, click changes over
trash bin:
- ALT-left-click: put cards on hand into trash (no undo!)
1402 card read / punch:
- currently only reading, no punching
- currently only lower right hopper functional; top file feed
(shute) inactive
- currently only LOAD button functional; all other buttons / switches inactive
- LOAD button loads one card into 1401 memory at location
001, and also starts this program if MODE switch on RUN
- 1401 read command ("1") reads card to memory location 001..080
- 1401 branch on last card ("BxxxA") available, if sense switch A set to ON
position
- ALT left click to right hopper to put cards
- left click or SHIFT/CTRL left click takes cards from hopper or from NR stacker back into
hand
- cards read are always output in stacker NR; currently no other stacker selectable
729 tape drive:
729 tape drive:
- currently only reading, no
writing
- for own read tests use tape #110, "personnel list".
Tape contains some records with personnel#/surname/name + tape mark
- click handle of slide window to lower or close
- click left hub to release / fix reel after slide window lowered
- [load/rewind] loads tape into vacuum columns and rewinds to load mark
- [load/rewind] fast rewinds tape if more than 0.5" on right reel
- [unload] unloads tape
- [start] switches to ready-state
- [reset] sets drive offline
- [chang.density] toggles density light, but has no further effect
- see IBM 1401 - let's program, #6: reading the IBM 729 tape drive for an example
tape reels in stands:
- may be taken if hand is empty
- may be put back into empty slot of tape stands
- may be put onto 729 tape drive, see there
- currently no change of labels or contents or type possible
- currently write-to-tape isn't working. For own read tests use tape #110, "personnel list".
Tape contains some records with personnel#/surname/name
Menu:
- hit ESC to open menu
- key assignment as usual
- graphics configuration as usual
- LOAD/SAVE: stores status/contents of tape stands and card drawers
known issues:
- core memory only up to address 999 (decoding above 999 not ready)
- currently no address calculation available
- currently no indexing available
- when 1402 is waiting for next card after "1" command, hit STOP before switching MODE
to other position than RUN, otherwise lamp status may be wrong
- currently write-to-tape isn't working. For own read tests use tape #110, "personnel list".
Tape contains some records with personnel#/surname/name