From VSI OpenVMS Wiki
Jump to: navigation, search

ACP_SWAPFLGS is a system parameter that enables or disables swap through the value of a 4-bit number for certain classes of ACPs, namely disks mounted /SYSTEM, disks mounted /GROUP, private disks, and magnetic tapes ACPs.

Classes of ACPs

Bit Class of ACP
0 Disks mounted by MOUNT/SYSTEM
1 Disks mounted by MOUNT/GROUP
2 Private disks
3 Magnetic tape ACP

If the value of the bit is 1, the corresponding class of ACPs can be swapped. The value of decimal 15 (hexadecimal F---all bits on) enables swap for all classes of ACP. A value of decimal 14 disables swap for ACPs for volumes mounted with the /SYSTEM qualifier but leaves swap enabled for all other ACPs. Note that one has only disk ACPs present if they are specifically requested at mount time or if a Files-11 On-Disk Structure Level 1 disk is mounted. In general, only bit 3 is significant because usually no file ACPs exist.