[unix-history] / usr / src / sbin / fsck / SMM.doc / 1.t

.\" Copyright (c) 1982 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)1.t	4.2 (Berkeley) %G%
.\"
.ds RH Introduction
.NH
Introduction
.PP
This document reflects the use of
.I fsck
with the 4.2BSD and 4.3BSD file system organization.  This
is a revision of the
original paper written by
T. J. Kowalski.
.PP
When a UNIX
operating system is brought up, a consistency
check of the file systems should always be performed.
This precautionary measure helps to insure
a reliable environment for file storage on disk.
If an inconsistency is discovered,
corrective action must be taken.
.I Fsck
runs in two modes.
Normally it is run non-interactively by the system after 
a normal boot.
When running in this mode,
it will only make changes to the file system that are known
to always be correct.
If an unexpected inconsistency is found
.I fsck
will exit with a non-zero exit status, 
leaving the system running single-user.
Typically the operator then runs 
.I fsck
interactively.
When running in this mode,
each problem is listed followed by a suggested corrective action.
The operator must decide whether or not the suggested correction
should be made.
.PP
The purpose of this memo is to dispel the
mystique surrounding
file system inconsistencies.
It first describes the updating of the file system
(the calm before the storm) and
then describes file system corruption (the storm).
Finally,
the set of deterministic corrective actions
used by
.I fsck
(the Coast Guard
to the rescue) is presented.
.ds RH Overview of the File System
Commit	Line	Data
a38b2411 KM	1	.\" Copyright (c) 1982 Regents of the University of California.
	2	.\" All rights reserved. The Berkeley software License Agreement
	3	.\" specifies the terms and conditions for redistribution.
	4	.\"
6a1194d8	5	.\" @(#)1.t 4.2 (Berkeley) %G%
a38b2411 KM	6	.\"
	7	.ds RH Introduction
	8	.NH
	9	Introduction
	10	.PP
	11	This document reflects the use of
	12	.I fsck
6a1194d8	13	with the 4.2BSD and 4.3BSD file system organization. This
a38b2411 KM	14	is a revision of the
	15	original paper written by
	16	T. J. Kowalski.
	17	.PP
	18	When a UNIX
	19	operating system is brought up, a consistency
	20	check of the file systems should always be performed.
	21	This precautionary measure helps to insure
	22	a reliable environment for file storage on disk.
	23	If an inconsistency is discovered,
	24	corrective action must be taken.
	25	.I Fsck
	26	runs in two modes.
	27	Normally it is run non-interactively by the system after
	28	a normal boot.
	29	When running in this mode,
	30	it will only make changes to the file system that are known
	31	to always be correct.
	32	If an unexpected inconsistency is found
	33	.I fsck
	34	will exit with a non-zero exit status,
	35	leaving the system running single-user.
	36	Typically the operator then runs
	37	.I fsck
	38	interactively.
	39	When running in this mode,
	40	each problem is listed followed by a suggested corrective action.
	41	The operator must decide whether or not the suggested correction
	42	should be made.
	43	.PP
	44	The purpose of this memo is to dispel the
	45	mystique surrounding
	46	file system inconsistencies.
	47	It first describes the updating of the file system
	48	(the calm before the storm) and
	49	then describes file system corruption (the storm).
	50	Finally,
	51	the set of deterministic corrective actions
	52	used by
	53	.I fsck
	54	(the Coast Guard
	55	to the rescue) is presented.
	56	.ds RH Overview of the File System