NAME

FDPERF− fast-disk performance control environment variable

SYNOPSIS

setenv FDPERF value

DESCRIPTION

The FDPERF environment variable allows the calling program to alter the tradeoff between performance and shared access made by the Fast-Disk filesystem management software.  Value is a number specifying one of the following modes of behavior.  Refer to fd_perf(3H) for a more comprehensive description of these modes.

0 Normal mode:  the user trades speed for multi-process access. 

1 Exclusive mode:  the user trades away multi-process access to obtain increased speed. 

2 “Assume idle” mode:  a hybrid of the first two modes, achieving speed advantages of Normal mode while maintaining the multi-process accessibility of the disk hardware.  Write accesses to the Fast-Disk are prohibited in this mode. 

If the user application calls fd_perf(3H), then the value of the FDPERF environment variable is ignored.  If FDPERF is not present in the environment, the default value of 0 is assumed. 

SEE ALSO

fd_perf(3H), libfd(3H), fdreqwait(7)

Pixar Fast-Disk Product Tutorial

Release β  —  Last change: 3/2/89