Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83 (MC840302); site ecrcvax.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!qantel!lll-crg!seismo!mcvax!unido!ecrcvax!snoopy From: snoopy@ecrcvax.UUCP (Sebastian Schmitz) Newsgroups: net.unix-wizards Subject: Re: When write()ing to a raw device, what is known on return? Message-ID: <171@ecrcvax.UUCP> Date: Thu, 28-Nov-85 07:03:37 EST Article-I.D.: ecrcvax.171 Posted: Thu Nov 28 07:03:37 1985 Date-Received: Sat, 30-Nov-85 06:30:11 EST Organization: ECRC, D-8000 Muenchen 81, W. Germany Lines: 45 Summary: Expires: References: Sender: Reply-To: snoopy@ecrcvax.UUCP (Sebastian Schmitz) Followup-To: Distribution: Organization: European Computer-Industry Research Centre, Munchen, W. Germany Keywords: Actually when a write returns, one knows awfully little: here is a little excerpt, one of my colleagues found in a book. Its quite amusing, but correct, so I guess I'll put in in this bb. Love, Seb Excerpt follows: /***** ecrcvax:jokes / phoebe!micha / 8:25 am Nov 19, 1985*/ I quote here a paragraph from the book "Advanced UN*X Programming" by M.J.Rochkind that may reveal some of the characteristics of the system. It describes what would the system tell you (if it could speak) when you issue a 'write' system call (low level I/O, writes a buffer on the disc): I've taken note of your request, and rest assured that your file descriptor is OK, I've copied your data successfully, and there's enough disc space. Later, when it's convenient for me, and if I'm still alive, I'll try to put your data on the disc where it belongs. If I discover an error, then I'll try to print something on the console, but I won't tell you about it (indeed, you may have terminated by then). If you, or any of the other process, tries to read this data before I've written it out, I'll give it to you from the buffer cache, so, if all goes well, you'll never be able to find out when and if I've completed your request. You may ask no further questions. Trust me. And thank me for the speed reply. /* ---------- */ -- Love, Sebastian (Snoopy) "You haven't done it, till you've done it with pointers" \!mcvax\!unido\!ecrcvax\!snoopy /* N.B. valid csh address */