RTC(3)RTC(3)NAMErtc - 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 associ‐
ated non-volatile memory. Physical devices supported 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 January 1970 00:00 GMT.
The clock is set by writing the desired number of seconds since the
epoch to the file. Setting the time in this device has no effect on
system time returned by /dev/time (see cons(3)), which must be set sep‐
arately 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 stan‐
dards 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 number of the
device, set during manufacturing. The file exists only if a particular
device provides such a number.
SOURCE
/os/*/devrtc.c
SEE ALSOcons(3)BUGS
The rtc file returns seconds but /dev/time returns microseconds: it's
history.
RTC(3)
