RTC(3)                                                     RTC(3)

     NAME
          rtc - real-time clock and non-volatile memory

     SYNOPSIS
          bind -b '#r' /dev

          /dev/rtc
          /dev/rtcid
          /dev/nvram

     DESCRIPTION
          The rtc device provides access to the real-time clock and
          any associated non-volatile memory.  Physical devices sup-
          ported include the Mostek MK48T12-15 Zeropower/Timekeeper,
          the Dallas Semiconductor DS1687 real-time clock, and the IBM
          PC real-time clock on various platforms.

          The rtc file when read returns the time as a decimal number,
          expressed as the number of seconds since the epoch, 1 Jan-
          uary 1970 00:00 GMT.  The clock is set by writing the
          desired number of seconds since the epoch to the file.  Set-
          ting the time in this device has no effect on system time
          returned by /dev/time (see cons(3)), which must be set sepa-
          rately if desired.  For example, when rtc is available
          osinit (see init(8)) uses it to set /dev/time.

          The nvram file provides access to the non-volatile memory
          commonly implemented by these clock chips.  There are no
          cross-platform standards for the range of addresses that can
          be safely used by Inferno, or for the content and format of
          the data.

          The rtcid file holds a decimal number giving the serial num-
          ber of the device, set during manufacturing.  The file
          exists only if a particular device provides such a number.

     SOURCE
          /os/*/devrtc.c

     SEE ALSO
          cons(3)

     BUGS
          The rtc file returns seconds but /dev/time returns microsec-
          onds: it's history.