> I am trying to select a host machine for a dedicated NTP server. I > have several spare PCs to hand, with processor speeds around 500 MHz > - all my budget will allow for the moment.
You will probably get more/better responses from comp.protocols.time.ntp on usenet. My 2 cents... There are several issues. The main ones are hardware and software. Almost any old PC will make a reasonable NTP server. But how good do you want? (This the time-nuts mailing list. You might want real good.) The speed of the CPU is not a major issue. It roughly cancels out: delays on the receive path are compensated by similar delays on the transmit path. As a sanity check, several people use the Soekris Engineering net4501 as a NTP server. http://www.soekris.com/net4501.htm It's got a 133 Mhz 486 class processor. (Runs cool.) The main source of instability is the temperature of the crystal. NB: Self heating is significant. My mostly idle systems show conspicuous glitches at 4AM when the cron jobs fire off. Aside from that, they easily track the daily temperature changes in my house. My main system has lots of noise when I'm doing things. It's not hard to use an NTP server to measure temperature. http://www.megapathdsl.net/~hmurray/ntp/slope.gif http://www.ijs.si/time/temp-compensation/ Most systems use the 32 KHz battery backed TOY (Time-of-Year) clock for timekeeping rather than the CPU crystal. This is good because it's generally farther from the heat generating CPU than the CPU crystal. For software, the PPS support needed by GPS clocks (and others) is part of the normal source code for some OSes. It's not on Linux but is available as an add-on. I suggest using whatever you are most comfortable/familiar with. If you don't have a GPS gizmo already, the Garmin GPS 18-LVC seems to be the current best-buy. It's under $100. Mine works well. I got it from Provantage. I don't know anything about UK availability. -- The suespammers.org mail server is located in California. So are all my other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited commercial e-mail to my suespammers.org address or any of my other addresses. These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
