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idtune -- Command Set a tunable system value /etc/conf/bin/idtune [-fm] switch value The command idtune lets you ``tune'' a variable in the COHERENT kernel. It also performs some sanity checking, to help ensure that you do not set a value to an impossible value. It and the related command cohtune largely replace the need for the command patch. To use idtune, simply invoke it along with the variable you wish to modify and the value to which you wish to set it. For example, to change the maximum size of a shared-memory segment to 128,000 bytes, type the command: /etc/conf/bin/idtune SHMMAX 128000 For the new setting to come into effect, you must use the command /etc/conf/bin/idmkcoh to build a new kernel, and then boot the newly built kernel. idenable recognizes the following two command-line options: -f idtune by default will ask you if you are sure that you want to make a given change. This option suppresses that behavior. -m Check that the value of switch is no less than value. If the value switch is less than value, then idtune raises it to value; otherwise, it leaves the value of switch alone. idtune works by modifying the file /etc/conf/stune, which holds the values of system variables that users can set. stune consists of a series of entries like the following: LOOP_COUNT 16 DUMP_USERS 2 MONO_COUNT 0 VGA_COUNT 4 The allowed range of values for a given variable is set in file /etc/conf/mtune, which consists of a series like the following: STREAMS_HEAP 8192 32768 131072 MONO_COUNT 0 4 8 VGA_COUNT 0 4 8 NBUF_SPEC 0 0 5000 NHASH_SPEC 0 1021 5000 NINODE_SPEC 0 128 1024 NCLIST_SPEC 0 64 1024 The first column gives the variable, the second gives its minimum allowable value, the third gives its default value, and the last its maximum value. You can read mtune and stune to see what kernel variables you can set, and to find the range of values allowed for each. Note, however, that you must never modify stune or mtune by hand. If you do so, you may build a kernel that is unbootable or that trashes your file system. See Also cohtune, commands, idenable, idmkcoh