CONFIG locations 600-622 are copied into the REX INFO table during SIR.
They can be modified and followed by an IPL in order to configure IRIS as needed.
See the Manager Reference manual for more info on these fields.
See the file R75DEFS for a complete list of everything that is in the INFO table.
600 == SYSTEM CREATION DATE (# HOURS AFTER 1-1-76)
601 == AVG CPU SPEED (INSTR/MSEC) + NOVA 3 FLAG
Instructions per millisecond. See this Post on how to set this value for the simH nova.
The 100000 bit was used to identify a Nova 3 computer, which then told SIR to make some special modifications in the interrupt handler.
602 == MAXIMUM # INSTALLED LOGICAL UNITS
CONFIG 1400 defines which drivers and partitions can be installed. This parameter (602) limits how many can be installed at any one time.
603 == NUMBER OF DATA CHANNELS PER PORT
Sets how many channels a BASIC program can have open. Of course, BASIC channel numbers are origin zero and decimal, so if (603) is set to 10 (octal) then BASIC has channels zero to seven. There is a minimum value for this field (probably 2), since certain IRIS processors open files on channels as well.
604 == LOCATION OF PORT CONTROL AREA
See Manager reference manual. Traditionally set at about 66000 to accommodate $MMUX.
605 == TOTAL NUMBER OF ACTIVE PORTS
This includes both interactive ports (with active files) and non-interactive ports which are commonly used for peripheral devices (printers).
606 == SPCECIAL CONDITIONS FLAG
As of R7.5, only one flag was defined. Setting the 100000 bit told REX to disallow any dirty pages in the buffer pool.
607 == MINIMUM BEGINNING OF USER STORAGE
610 == TOP WORD OF CORE TO BE USED
For all 64KW implementations, this can be set to 177777.
611 == AUXILIARY BUFFER SIZE (NUMBER OF WORDS)
Set to 1004 to allow indexed files.
612 == MAG TAPE BUFFER SIZE (NUMBER OF WORDS)
Set to zero if no mag tape driver is loaded.
613 == NUMBER OF EXTRA CHARACTER QUEUE NODES
614 == MINIMUM NUMBER OF FREE NODES
615 == NUMBER OF SIGNAL BUFFER NODES
616 == MAXIMUM NUMBER OF DISCSUBS
617 == LONG\SHORT TIME SLICE
620 == MIN.TIME A LOCKED PARTITION IS KEPT LOCKED
621 == not defined
622 == not defined