1UPDATE(8)                   System Manager's Manual                  UPDATE(8)
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NAME

6       update - periodically update the super block
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SYNOPSIS

9       /etc/update
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DESCRIPTION

12       Update  is  a program that executes the sync(2) primitive every 30 sec‐
13       onds.  This insures that the file system is fairly up to date  in  case
14       of  a  crash.  This command should not be executed directly, but should
15       be executed out of the initialization shell command file.
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SEE ALSO

18       sync(2), sync(1), init(8)
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BUGS

21       With update running, if the CPU is halted just as the sync is executed,
22       a  file  system  can be damaged.  This is partially due to DEC hardware
23       that writes zeros when NPR requests fail.   A  fix  would  be  to  have
24       sync(1) temporarily increment the system time by at least 30 seconds to
25       trigger the execution of update.  This would give 30 seconds  grace  to
26       halt the CPU.
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