NAME
update - periodically update the super block
SYNOPSIS
update
DESCRIPTION
Update is a program that executes the sync primitive every
30 seconds. This insures that the file system is fairly up
to date in case of a crash. This command should not be exe-
cuted directly, but should be executed out of the initial-
ization shell command file. See sync (II) for details.
SEE ALSO
sync (II), init (VIII)
BUGS
With update running, if the CPU is halted just as the sync
is executed, a file system can be damaged. This is par-
tially due to DEC hardware that writes zeros when NPR
requests fail. A fix would be to have sync temporarily
increment the system time by at least 30 seconds to trigger
the execution of update. This would give 30 seconds grace
to halt the CPU.
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