This is a variation of RTLinux for kernel 2.0.33 by Barabanov, Yodaiken and
company, NMT, New Mexico, USA. (http://rtlinux.cs.nmt.edu/~rtlinux/)
People at NMT must be praised for their nice work without which this variant
would not exist. 
It fixes the fpu supports so that all the stuff now works, without causing
unpredictable jitters, either if the fpu is used or not.
This new version of the variant is for uniprocessor (UP) PCs and allows now 
to chose between a periodic and a oneshot timing, a feature found in the
official RTLinux SMP alpha release 1.2a for 2.1.90.
The fix ticking is less flexible but, with the usual PC hardware (UPs cannot 
use APICs), much more efficient. So it is up to you which one to choose.  
It should be noted that the real time is now measured on the base of the CPU
clock (time stamp clock) and not on the 8254 chip, that is used only to generate
interrupts.
I think that such a feature is not available on 486 machines and thus this
variant requires Pentium and onward machines. If you have a 486 use version 0.6.
It has a correct fpu support but only a periodic scheduler.
It needs to calibrate the clock. You have two choices:
- the first, and less precise, gets the cpu frequency from bogomips. Just
  type "cat /proc/cpuinfo" and read it;
- the second requires running the module "rt_cal.o" from the directory  
  "calibration" included in this distribution. Yuo'll get something better than
  bogomips in about ten seconds. If you want to get full precision let it run
  still the least significant digit is stabilized. See README in "calibrate" 
  for a more precise description.
This variant of rtlinux has also more services including: timings, semaphores,
messages and remote procedure calls, that makes it easier to develop complex
real time applications.
Its installation requires that you already know how to install rtlinux-0.6.

What to do:
	1 - Apply the rtlinux-0.6 patch for linux 2.0.33, as explained in the
	    NMT official distribution, do "make menuconfig" but do not 
	    "make zImage" immediatly;
	2 - Copy the files rt_time.c, rt_time.h, time.c, ksyms.c, rt_sched.h
            and rt_prio_sched.c of this distribuition over, i.e.replace,
	    their corresponding in the appropriate linux directories.
	    The file "copyto" (included), appropriately edited and made
	    executable, can be of help;
	3 - Carry out the compilation of the kernel by "make zImage";
	4 - Get the cpu frequency as described above and set the macro CPU_FREQ
	    in rt_prio_sched.c accordingly.
	5 - Do "make modules";

Before carrying on step 2 it is suggested to save the original file to be
overwritten. Note again that the script file "copyto" does this already.
The file "ldmod" and "remod" can be used to insmod and rmmod the scheduler and
the fifo modules.

Now you are done and can try the test cases.

Be carefull in setting the macro TICK_PERIOD in the various examples to a value
appropriate to your machine (nanosecs). The one now used works for a 200Mhz
PentiumPro and can be too demanding for lower class Pentiums.
In all the tests the choice of which timer, periodic or oneshot, to use is done
by commeting/uncommentig the macro ONE_SHOT. It is important to remark that
the default choice of the scheduler is for a periodic timing, to chose the
oneshot mode "rt_set_oneshot_mode()" must be called before any time conversion
or service is required to the scheduler. In the case of a multi module
application set the mode in the very first module to be loaded.
You will not see any copyright whatsoever in this software and you can use it
as you like but I would like "to be remembered" if you'll find it usefull. 
As usuall it is "as it is" and I assume no responsability if anything goes
wrong. However comments and any feedback are warmly welcomed, email them at:
"mantegazza@aero.polimi.it".