panic() design question

Chris Torek chris at mimsy.umd.edu
Sat Aug 25 14:37:35 AEST 1990


In article <24280 at adm.BRL.MIL> dave at tis.com (David I. Dalva) asks
why the 4BSD and SysVR? (neither release number nor platform mentioned,
although these have a great deal of significance) kernels attempt to
sync the disks on a call to panic:

>Why is it that panic calls sync() (or update()) before the system is
>halted, when data structures may be messed up causing further damage to
>the filesystem?

In general, the panic is due to something relatively minor, and the
sync makes things better instead of worse.  Very occasionally (especially
after mucking with the filesystem code :-) ) it has the opposite effect,
but overall the sync was deemed to be a win.

(Anyway, system developers can always disable it temporarily.)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 405 2750)
Domain:	chris at cs.umd.edu	Path:	uunet!mimsy!chris



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