About TODO Blog RSS Old blog Projects Gallery Notes

Fri, 12 Jan 2007

Climbing eveninig.


Short but quite productive training - not too much traces were completed, since training started one hour after usual start at 18-30, but nevertheless I completed several warming simple traces and four quite complex old traces - found that some of them were slightly changed, which forced me to fail, but only for a moment. I was not 100% recovered from previous (first time this year) training, so I did not even tried something completely new and really complex, but nevertheless body is aching and that is a good sign.

/life :: Link / Comments (0)

SMP scalability in M-on-N threading model.


Actually it is simple.
Since only kernel can schedule thread (actually not even thread or process, but its own kernel's representation, so called kernel's virtual process) to run on specified CPU, M-on-N threading model should have several real threads (for example several current POSIX threads), its number should be equal to number of real CPUs, and then library layer will schedule execution of context of different real threads, each of which in turn can run on separate CPU.

So, userspace will create new real threads when pthread_create() is called until number of them is less than number of real CPUs, each real thread in turn is a context in the global tree of contexts, where fake context will be added with all subsequent pthread_create() calls, and userspace scheduler (backed by real threads) will pick up several contexts from the tree and execute them on the real CPUs.

Simple and looks really good.

/devel/threading :: Link / Comments (0)

Buy Sealand.


Sealand is small island/platform situated at a distance of approximately 7 nautical miles from the coast of UK in North Sea.
It has sovereignty.
One can buy (and/or develop) her/his own nation there with own laws, which in turn allows to register there some firms without any taxes even better than today's off-shores.
Its price is $500 millions, but there are other islands too, which prices start from just $50k.

For example this set of islands with price less than $250k, althgough I'm not sure that one can declare a sovereignty there.

/other :: Link / Comments (0)

Winter in Russia.


One year ago temperature in Moscow was 2 degrees higher than in Antarctica, it was the coldest winter in the history (with instrumental measurements). Now we have about +/-1 degrees Centigrade - the hottest winter in the history.

Winter is a time of planned Matrix update. To get calculation resources for garbage collection, Matrix shortens light day, removes leafs from trees, and paints sky into uniform gray colour. This reduces picture calculation. Previously Matrix covered the whole surface with uniform white snow, but with new powerfull servers it is not needed anymore. One says, that after next upgrade there will not be any need for dedicated winter at all.

/other :: Link / Comments (0)