Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 SMI; site sun.uucp Path: utzoo!watmath!clyde!cbosgd!ihnp4!ucbvax!decvax!decwrl!sun!guy From: guy@sun.uucp (Guy Harris) Newsgroups: net.unix-wizards Subject: Re: tar fs copy Message-ID: <2819@sun.uucp> Date: Tue, 24-Sep-85 02:12:51 EDT Article-I.D.: sun.2819 Posted: Tue Sep 24 02:12:51 1985 Date-Received: Thu, 26-Sep-85 06:22:00 EDT References: <832@burl.UUCP> <221@drivax.UUCP> <842@burl.UUCP> <240@investor.UUCP> <233@drivax.UUCP> <249@investor.UUCP> <239@drivax.UUCP> Organization: Sun Microsystems, Inc. Lines: 21 > Pipes use an inode on the root file system. Not in systems since V7; in V7, a "pipe device" was added, so that you can put pipes on other file systems if you want. Other systems, like 4.2BSD, use mechanisms other than pseudo-files to buffer pipe data. > They are limited to 5120 bytes on System V, and 4096 on some other systems, > by code in the kernel. To clarify - this is not a limit on the total amount of data which can be poured down a pipe (which seems to be what the previous poster was worried about, since they were using something like two piped-together "tar"s to copy a huge file system). This is a limit on how much data can be buffered in a pipe before the writer is blocked. Chances are slim (if not nil) that you won't be able to copy a big file system using piped-together "tar"s because of the pipe filling up the file system (unless, of course, you're moving data to the file system on which the pipes exist). Guy Harris