From owner-freebsd-doc Thu Nov 1 6: 9:55 2001 Delivered-To: freebsd-doc@freebsd.org Received: from flood.ping.uio.no (flood.ping.uio.no [129.240.78.31]) by hub.freebsd.org (Postfix) with ESMTP id 2D84437B406 for ; Thu, 1 Nov 2001 06:09:50 -0800 (PST) Received: by flood.ping.uio.no (Postfix, from userid 2602) id 74BDC14C2E; Thu, 1 Nov 2001 15:09:48 +0100 (CET) X-URL: http://www.ofug.org/~des/ X-Disclaimer: The views expressed in this message do not necessarily coincide with those of any organisation or company with which I am or have been affiliated. To: doc@freebsd.org Cc: Paul Robinson Subject: FAQ addition From: Dag-Erling Smorgrav Date: 01 Nov 2001 15:09:47 +0100 Message-ID: Lines: 8 User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" Sender: owner-freebsd-doc@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org --=-=-= Please see attached patch. DES -- Dag-Erling Smorgrav - des@ofug.org --=-=-= Content-Type: text/x-patch Content-Disposition: attachment; filename=dev-null.diff Index: doc/en_US.ISO8859-1/books/faq/book.sgml =================================================================== RCS file: /home/ncvs/doc/en_US.ISO8859-1/books/faq/book.sgml,v retrieving revision 1.279 diff -u -r1.279 book.sgml --- doc/en_US.ISO8859-1/books/faq/book.sgml 2001/10/31 23:26:02 1.279 +++ doc/en_US.ISO8859-1/books/faq/book.sgml 2001/11/01 14:08:37 @@ -11563,6 +11563,62 @@ Please do not reproduce without attribution. + + + + Where does data written to /dev/null + go? + + + It goes into a special data sink in the CPU where it + is converted to heat which is vented through the heatsink + / fan assembly. This is why CPU cooling is increasingly + important; as people get used to faster processors, they + become careless with their data and more and more of it + ends up in /dev/null, overheating + their CPUs. If you delete /dev/null + (which effectively disables the CPU data sink) your CPU + may run cooler but your system will quickly become + constipated with all that excess data and start to behave + erratically. If you have a fast network connection you + can cool down your CPU by reading data out of /dev/random + and sending it off somewhere; however you run the risk of + overheating your network connection and / or angering your + ISP, as most of the data will end up getting converted to + heat by their equipment, but they generally have good + cooling, so if you don't overdo it you should be + OK. + + Paul Robinson adds: + + There are other methods. As every good sysadmin knows, + it is part of standard practise to send data to the screen + of interesting variety to keep all the pixies that make up + your picture happy. Screen pixies (commonly mis-typed or + re-named as 'pixels') are categorised by the type of hat + they wear (red, green or blue) and will hide or appear + (thereby showing the colour of their hat) whenever they + receive a little piece of food. Video cards turn data into + pixie-food, and then send them to the pixies - the more + expensive the card, the better the food, so the better + behaved the pixies are. They also need constant simulation + - this is why screen savers exist. + + To take your suggestions further, you could just throw + the random data to console, thereby letting the pixies + consume it. This causes no heat to be produced at all, + keeps the pixies happy and gets rid of your data quite + quickly, even if it does make things look a bit messy on + your screen. + + Incidentally, as an ex-admin of a large ISP who + experienced many problems attempting to maintain a stable + temperature in a server room, I would strongly discourage + people sending the data they don't want out to the + network. The fairies who do the packet switching and + routing get annoyed by it as well. + + --=-=-=-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-doc" in the body of the message