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

Jim Lux jimlux at earthlink.net
Sun May 4 12:30:33 EDT 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"

http://www.gaisler.com/index.php/products/processors/leon3

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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