From 073438ae9acd099045b62f2d7fa62067ac0ffb51 Mon Sep 17 00:00:00 2001 From: CSRG Date: Sun, 5 Jun 1983 15:59:47 -0800 Subject: [PATCH] BSD 4_2 development Work on file usr/man/man8/update.8 Synthesized-from: CSRG/cd1/4.2 --- usr/man/man8/update.8 | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 usr/man/man8/update.8 diff --git a/usr/man/man8/update.8 b/usr/man/man8/update.8 new file mode 100644 index 0000000000..a497a3b8ce --- /dev/null +++ b/usr/man/man8/update.8 @@ -0,0 +1,36 @@ +.TH UPDATE 8 "4 February 1983" +.SH NAME +update \- periodically update the super block +.SH SYNOPSIS +.B /etc/update +.SH DESCRIPTION +.I Update +is a program that executes +the +.IR sync (2) +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 executed directly, +but should be executed out of the +initialization shell command file. +.SH "SEE ALSO" +sync(2), sync(8), init(8), rc(8) +.SH BUGS +With +.I update +running, +if the CPU is +halted just as +the +.I sync +is executed, +a file system can be damaged. +This is partially due to DEC hardware that +writes zeros when NPR requests fail. +A fix would be to have +.IR sync (8) +temporarily increment the system time by at +least 30 seconds to trigger the execution of +.I update. +This would give 30 seconds grace to halt the CPU. -- 2.20.1