The first in an occasional series, with the occasion being that I finish reading a book.
Nineteenth Street NW, a financial thriller by Rex Ghosh, an economist at the IMF. There's a rule of thumb in the book biz that the cover blurbs on good books are reviews of the book by real reviewers, on so-so books are reviews of the author's previous books, and on bad books are by the author's friends. This book's blurbs are by Simon Johnson and Paul Volcker. Uh, oh.
Friday, 21 January 2011
In virtual memory operating systems, copy on write (COW) is a well known technique to save time and space. The idea is that several processes have logically separate writable pages of data that happen to have the same contents, because they were initialized from the same source. So long as nobody writes into a page, all the processes can share the same copy. If a process does write into it, the operating system makes a separate copy of the the changed page. The best known application for COW is the Unix fork() primitive, although it also is useful for writable program data that is initialized from a file, a common situation in modern operating systems with shared libraries.