30.10.2014 Views

Operating Systems - David Vernon

Operating Systems - David Vernon

Operating Systems - David Vernon

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Processes<br />

InterProcess Communication IPC<br />

– Semaphores (Dijkstra 1965)<br />

»UP<br />

generalization of WAKEUP<br />

ATOMIC<br />

OPERATION<br />

increments semaphore value<br />

if there is one or more processes<br />

sleeping on the semaphore<br />

then<br />

choose a process at random<br />

unblock it<br />

(allow it to complete its DOWN operation)<br />

Copyright © 2007 <strong>David</strong> <strong>Vernon</strong> (www.vernon.eu)

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!