Reliability of System V 1K file system

[Conor P. Cahill]

In article <1990Sep22.160132.24999 at hq.demos.su> avg at 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).



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Conor P. Cahill            (703)430-9247        Virtual Technologies, Inc.,
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