Xref: utzoo comp.unix.questions:25679 comp.unix.sysv386:631
Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!virtech!cpcahil
From: cpcahil@virtech.uucp (Conor P. Cahill)
Newsgroups: comp.unix.questions,comp.unix.sysv386
Subject: Re: Reliability of System V 1K file system
Keywords: System V, reliability, file systems
Message-ID: <1990Sep22.215128.16693@virtech.uucp>
Date: 22 Sep 90 21:51:28 GMT
References: <5869@suns302.cel.co.uk> <1990Sep22.041723.1599@pilikia.pegasus.com> <1990Sep22.160132.24999@hq.demos.su>
Reply-To: cpcahil@virtech.UUCP (Conor P. Cahill)
Organization: Virtual Technologies Inc., Sterling VA
Lines: 34

In article <1990Sep22.160132.24999@hq.demos.su> avg@hq.demos.su (Vadim G. Antonov) writes:
>	algorithms: the 2.9's kernel performed critical file system
>	operations in the strict order - for exmaple it guarantees
>	that if you delete a file inode will be cleared before releasing
>	data blocks which in turn will be done before releasing this inode.

This is the same as (or very similar to) the algorithm used in "today's"
system V implementations.

>	Thus if power would fail during removing a file the worst thing
>	which can happen is missed blocks - but generally file structure
>	will remain correct. There are some similar tricks in BSD 2.9,

This is partially wrong.  This software change only guards against a system
stop where there are no hardware glitches.  A power failure can wreak havoc
all over the system if the *hardware* does not correctly handle the loss
of power during an otherwise normal operation.  From the original posting
about this problem, I would sumise that his hardware has some problems
with power loss (or that a simple power loss is not the only thing
happening).


>	but I do not want to describe it - get sources and read it
>	yourself. Hmmm... +1 to BSD over SysV.

No.  In this simple test they are about the same (and they are growing
closer every day).



-- 
Conor P. Cahill            (703)430-9247        Virtual Technologies, Inc.,
uunet!virtech!cpcahil                           46030 Manekin Plaza, Suite 160
                                                Sterling, VA 22170