Date: Sun, 17 Feb 2002 12:03:53 -0700 (MST) From: Ronald G Minnich <rminnich@lanl.gov> To: <hackers@FreeBSD.ORG> Cc: <freebsd-questions@FreeBSD.ORG> Subject: Re: in-kernel HTTP Server for FreeBSD? Message-ID: <Pine.LNX.4.33.0202171200020.5188-100000@xed.acl.lanl.gov> In-Reply-To: <xzpit8wdkmb.fsf@flood.ping.uio.no>
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On 17 Feb 2002, Dag-Erling Smorgrav wrote: > Roy Sigurd Karlsbakk <roy@karlsbakk.net> writes: > > > sendfile() isn't zero-copy, it's just two-less-copies. > > zero-copy means "zero copy-operations within memory" > > To an MCSE, maybe. I think Roy is right. AFAIK the term "zero copy" was invented by Van Jacobsen ca. 1990 to describe an optimized TCP stack he had working with the Witless interface project he did with HP, while he was still at LBL. Witless was an FDDI interface with interesting properties -- still well worth studying today. And, there was one copy in the TCP for Witless. You had to read "zero copy" to mean "Zero copies more than the absolute minimum". When we did the MINI interface at the SRC (ca. 1994), which had one less copy than Witless, we jokingly called it a "-1 copy" interface. ron To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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