[time-nuts] Low cost GPS module for < 100ns timestamping error

Jim Lux jimlux at earthlink.net
Sun May 4 16:30:33 UTC 2014

On 5/4/14, 8:40 AM, Chris Albertson wrote:
> Looks like this is all you'd need for most timing projects.  Just add your
> favorite OCXO and some wire.
> The SPARC (not Spark) is actually a step up from ARM.  It was developed by
> Sun Microsystems (now Oracle) it is optimized for things like fast context
> switching, multi tasking and so on, all the things done by operating
> systems. The Sparc V8 does 128 bit floating point, (quad precision) I
> wonder if 200Kb RAM is enough to run an older version of SunOS?  (a BSD
> variant.)

Not all SPARC V8s have FPU: the SPARC spec has a lot of flexibilty in 
implmentation: a lot of "if you want X, then it has to do the following 
things in the following way, but it's optional"


There's multiprocessor versions. Versions with and without cache, 
versions with and without FPU, etc.

If you want a POSIX compliant OS, then RTEMS will definitely fit in 
200kbytes. Don't know about all the other options.  I've never heard of 
a SunOS implementation on LEON, but there's a lot of weird stuff out 
there.  You do want to make sure that whatever you use is reasonably 
complete and of a reasonably recent version (or at least one you're real 
familiar with).

There are a fair number of "one-off" ports of some OS or another to the 
LEON, but which don't have any continuing support, bug fixes, or users 
to contribute.  Imagine a grad student doing their thesis on "An 
implementation of RSX-11M supervisor mode on the LEON3-MP"... they get 
enough done to demonstrate that it works, and they graduate, and who has 
a bunch of RSX-11M software anyway.

> Are these shipping yet?

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