Path: utzoo!utgpu!watmath!uunet!xanth!nic.MR.NET!hal!cwjcc!gatech!rutgers!noao!asuvax!nud!mcdchg!ddsw1!fluke!vince From: vince@tc.fluke.COM (Craig Johnson) Newsgroups: unix-pc.general Subject: Accurate Timekeeping Keywords: real time clock, system time Message-ID: <6163@fluke.COM> Date: 1 Dec 88 01:27:37 GMT Sender: news@tc.fluke.COM Organization: John Fluke Mfg. Co., Inc., Everett, WA Lines: 46 I have gotten tired of my 7300 keeping inaccurate time. A long time ago there was a program floating around which caused a daemon to start up which applied periodic adjustments to the system time. Was this ever posted here or was it a commercial product? If it is public domain could someone send me a copy or repost it? Does anyone know if this program updates the real time clock hardware, or only the system time kept in software? If this doesn't show up, there may be a way to easily improve your system's timekeeping anyway. It turns out that the system time is only set (read from the real time clock hardware) on boot-up. This is performed by "date -" being executed by root. From that time forward until the next reboot, the system time is based on a different clock source. I haven't looked at the hardware manual yet to figure out if it is the microprocessor clock or yet another clock (for time slice interrupts?), but it is definitely different from what the RTC hardware sees. If your Unix-pc has been up for a while, login as someone other than root and type, $ date -; date "Date -" cannot change your system time since you are not root, but it will print out the time found in the real time clock hardware. If the hardware clock and the system clock (software) were keeping the same time you would expect the second date command to spit out a time which follows the first time by a couple of seconds. On my 7300 the time is considerably different, and it is the RTC value which tracks reality closest. So here is the proposal: If I can't get the time correction daemon program I'm looking for, I propose to add a line to my crontab which will execute "date -" once a day, thereby setting the system time to the RTC value daily. This should make life more tolerable for me, perhaps it will help others also. I'm making the assumption here that crontab is executed by smgr or cron which has root privileges. We'll see if this is good enough. If not, I will look into writing my own time correction daemon. I'll let you know if it comes to that. Craig V. Johnson ...!fluke!vince John Fluke Mfg. Co. Everett, WA