M.SDCB - set disk cache handling for a file.

Usage:

mme     m.sdcb

Input Q register

upper 0-17

0: bypass cache
1: write into
2: write through

lower 18-35

the lower 12 bits contain the BCD file code, and so bits 18-23 are zero.

Output Q register

major status, bits 0-17

0: disk cache enabled and running.
1: disk cache disabled in startup config.
2: cache enabled but not currently running.

minor status, bits 18-35

0: success.
1: unknown file code.
2: invalid option request in Q upper.
3: request not processed.

Description:

MME M.SDCB lets you change the disk cache handling for a disk file code. This is primarily of interest for dynamically attached permanent files. A file will have the system default cache handling, unless that is over ridden by an option on a $PRMFL card, or by a call to MME M.SDCB (or PMME P.SDCB).