Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn )
Newsgroups: comp.unix.questions
Subject: Re: tail -f
Message-ID: <9098@smoke.BRL.MIL>
Date: 7 Dec 88 15:16:45 GMT
References: <412@fedeva.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) )
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 8

In article <412@fedeva.UUCP> jbr0871@fedeva.UUCP (Blaine Robertson) writes:
>Can someone please tell me how 'tail -f' works?.  Obviously, it does not
>do a busy loop while doing a stat on the file.

All it does is to sleep for a short time (around one second), then
copy out everything past the last high water mark via read/write.
There is no statting, no asynchronous notification, no nonblocking
I/O, etc.  It IS a "busy loop" (except for the short sleep).