RTLinux/Open 3.1 is now available from: ftp://ftp.rtlinux.com/pub/rtlinux/v3/

New in 3.1

    * Both v2.4.4 and v2.2.19 kernels are supported
    * RTLinux modules are compiled correctly when module versioning is enabled
    * POSIX support fixes and enhancements
    * RT-threads can be created from other RT-threads with preallocated memory
    * Compatibility mode fixes (rt_get_time and others)
    * CLOCK_GPOS is a new POSIX clock that converges to the Linux system clock
    * The interrupt focus feature is also supported with 2.2.x kernels
    * CLOCK_REALTIME is now the same as CLOCK_RTL_SCHED
    * The new rtl_posixio RTF_SETSIZE ioctl can be used to change the fifo size

Note on POSIX clocks. There are 3 clocks available to the RTLinux programs:

- CLOCK_MONOTONIC. This essentially a scaled CPU cycle counter. It expresses
time passed since system bootup. The main use 

- CLOCK_REALTIME. This is the clock used for thread scheduling. sem_timedwait,
nanosleep, pthread_make_periodic_np and others use time values relative to
this clock. In oneshot (default) mode, time shown by this clock is the same
as that of CLOCK_MONOTONIC. In periodic mode, CLOCK_REALTIME becomes local
to the CPU.

- CLOCK_GPOS. This clock always converges to the Linux system clock and thus
is subject to ntpd adjustments etc.

