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Thread: The long way around to RTC Alternative

  1. #21
    Join Date
    May 2011
    Outer Mongolia


    I seem to recall for a while it was kind of a "thing" to buy a cheap burner cellphone to stash in your datacenter rack and use as a cellular clock source. Cellular time isn't as good as GPS but it usually penetrates datacenter walls a *little* better.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  2. #22


    Quote Originally Posted by Chuck(G) View Post
    Well, briefly, the Internet didn't exist in the heyday of the 8088...
    Chuck(G) is right.

    While the ARPAnet existed since 1969, it was not running TCP/IP until flag day: January 1, 1983. That is when communication with non-ARPAnet networks became possible.

  3. #23


    Eudimorphodon wins the prize for explaining why you need to run DHCP twice on a machine that doesn't have a battery backed real-time clock.

    I have thought about writing a variation of DHCP that gets a lease, contacts a timeserver, and then updates the lease time to the current/correct new time. But until I get that done, just running DHCP again after getting the time from the network is the way to go.

    If you are really hardcore, a Garmin 18X LVC will interface to your PC via a serial port and give you the time fairly accurately just by reading the timestamp from the serial port. Enable the 1PPS line and setup an interrupt handler on it to get an interrupt at the top of each second for bonus points. (That's how my PCjr is getting the time at the moment.)


  4. #24
    Join Date
    Jan 2007
    Pacific Northwest, USA
    Blog Entries


    WWV is still the vintage way to go, I think.

  5. #25


    Here I was thinking WWV just broadcast the 1000Hz tone every minute. Never knew about the additional encoded information until now

  6. #26


    There's also the 60 kHz longwave version, WWVB, used by many self-setting "atomic" clocks. WWVB only transmits a digital time code, no audio. Its signal is much less affected by time of day and atmospheric conditions than WWV's shortwave signals.

  7. #27
    Join Date
    May 2019
    San Diego CA


    This message cracks me up every time I boot now.
    40 year difference between DOS clock at 1-1-1980 and current date in 2020

    "Difference between suggested time and system time is greater than 10 minutes!"

    Really? I wouldn't have guessed!
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