Yikes! That would explain why the language's site is still Copyright 2011 Cadence Research Systems.

Apparently Cisco bought Cadence, and Chez Scheme fell through the cracks.

Ugh. As far as I know, perhaps not counting the 2 JVM Schemes, it was the only one that provided OS level non-green threads.

I've never used it myself, but fwiw Gauche also advertises support for native threads. SRFI-18 threads are wrapped around pthreads on Unixy platforms, and Windows threads on Windows. http://practical-scheme.net/gauche/man/gauche-refe_106.html

Ah, I was not clear enough: native SMP threads, as in each thread accessing the same shared memory heap. Gauche allocates a new VM for each thread ... ah, but I see it has data synchronization primitives. I believe it has moved forward since the last time I checked it, years ago.

Thanks for the tip!

Repeated from the other reply on Guile: Hmmm, now I'll have to narrow the statement to "The only native code compiling Scheme that I know of" (which is harder to do).

AFAIK, Guile's threads are native.

But it has RMS/GNU/FSF cooties!

If you play Philip Glass' Einstein on the Beach while using it, it will not be happy!

(We were roommates when he launched the GNU project, and he did not like that title, it would wake him out of a sound sleep. Which, if you've listened to it, is perfectly understandable, it's very minimalist, an acquired taste he did not share :-).

Hmmm, so it does, and as suiting its niche, at a low level. See above WRT Gauche; from a skim of the manual, Guile's VM may be reentrant or it hides that level of detail.

Thanks for the tip!

Hmmm, now I'll have to narrow the statement to "The only native code compiling Scheme that I know of" (which is harder to do).

>now I'll have to narrow the statement to "The only native code compiling Scheme that I know of"

Native compilation is on the roadmap for Guile, so hopefully you'll have to narrow that statement further in a couple of years. :)

> it would wake him out of a sound sleep

In that state, I'm pretty sure most people prefer Cage.

A bit of googling turned up this pricing sheet where Chez Scheme is listed on page 88 (it says $65 per unit or $325 for 10, so buy your Chez's in bulk!):

http://www.centurylink.com/business/asset/channel/cisco-us-g...

From whom can you go to buy a copy, and is it still under development?

The web site doesn't look like it's been touched since 2011, and Google searches constrained by site:cisco.com turn up nothing. Other searching showed no signs of life.