*BSD News Article 61771


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From: hosokawa@mt.cs.keio.ac.jp (HOSOKAWA Tatsumi)
Newsgroups: comp.unix.bsd.freebsd.misc,comp.os.linux.development.system
Subject: Re: The better (more suitable)Unix?? FreeBSD or Linux
Date: 11 Feb 1996 16:07:36 GMT
Organization: Tokoro Laboratory, Keio University, Yokohama Japan.
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In article <4fiq4k$if8@josie.abo.fi>
mandtbac@news.abo.fi writes:

>>  - BSD writes metadata synchronously, but data asynch. thus, if the
>> box goes down while data is not yet written, you end up with files
>> that seem, to the filesystem, OK, whereas they're really garbage.

I have two questions about this sync/async problems (I don't have
detailed knowledge about filesystem).

If the 'sync' operation on async filesystem is done in order of the
original write requests was issued, it's safe.  But I think it reduces
the performance of filesystem.

If it is done in unordered fashion, I think it causes the same (but
more critical) problems on async filesystem.  Is it wrong?

BTW, I've used BSD filesystem for years, I haven't see the dead file's
garbage appeared as another file even after severe crashes (I'm a
device driver writer of FreeBSD and I frequently experience unclean
shutdowns).  I've thought that these premature files are truncated by
fsck.  Is it wrong?

--
	HOSOKAWA, Tatsumi              E-mail: hosokawa@mt.cs.keio.ac.jp
	  WWW homepage: http://www.mt.cs.keio.ac.jp/person/hosokawa.html
	Department of Computer Science, Keio University, Yokohama, Japan