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From: gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>)
Newsgroups: net.unix-wizards
Subject: Re: When write()ing to a raw device, what is known on return?
Message-ID: <38@brl-tgr.ARPA>
Date: Mon, 25-Nov-85 10:15:53 EST
Article-I.D.: brl-tgr.38
Posted: Mon Nov 25 10:15:53 1985
Date-Received: Tue, 26-Nov-85 20:54:45 EST
References: <325@log-hb.UUCP>
Organization: Ballistic Research Lab
Lines: 8

> When a write to a raw disk partition returns, is anything known
> concerning whether data is actually on the disk or not?

Yes, the transfer is by DMA from user address space and it is
complete when the write() system call returns.  Block buffers
are not used for raw disk I/O.  Further, EIO is supposed to
be returned if the write fails; this is much better than in
the case of block I/O if you are concerned with reliability.