Appendix G

SX-MFF

The SX Memory File Facility (SX-MFF) constructs high performance file systems and a disk cache on the main memory unit. Since SX-MFF provides the similar functions as the extended memory unit (XMU), installing SX-MFF is useful for a system not equipped with XMU.

SX-MFF provides the following features.

(1) SX-MFF is a program product. Before using SX-MFF, it is necessary to install the package and relinking the kernel by the config(1M) command.

(2) SX-MFF occupies a fixed part of MMU from system start-up through shutdown. The contents, however, are cleared each time the system is started up. Therefore, reconstructing the file systems is necessary after system start-up.

(3) The system parameters for SX-MFF are set by the IOX install tool. (Refer to the Installation Guide.) The memory capacity allocated for SX-MFF should be carefully examined so that the remaining main memory is sufficient for job execution. Especially, in case the system is not SX-4 A model and a part of the main memory has been degraded due to a hardware failure, the memory capacity allocated for SX-MFF should be reset.

(4) The special file for SX-MFF is /dev/MSX4. The resource limitation group, I/O accounting group (refer to getrlimit(2-B), mount(1M-O)), the way to construct the file system, and the restrictions are the same as those applied to XMU. However, the device status of SX-MFF can neither be printed by prtconf(1M) nor changed by devconf(1M).

(5) The sub-partition sizes of SX-MFF are as follows.