Date: Tue, 19 Sep 2000 23:08:22 -0400 (EDT) From: Marc Tardif <intmktg@CAM.ORG> To: freebsd-hackers@freebsd.org Subject: writing(2) to raw devices Message-ID: <Pine.LNX.4.10.10009192302540.12429-100000@Gloria.CAM.ORG>
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From The Design and Implementation of the 4.4BSD Operating System, the write(2) system call must go through vn_write(), ffs_write(), ffs_balloc(), cluster(), bio() and finally dev() which performs the actual disk write. Considering all this block-oriented overhead, how can dd(1) which calls write(2), perform raw io on devices such as /dev/rwd0? Doesn't write(2) confine the process to block io by its very nature? To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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