Night writing visited the National Institute for the Blind in Paris, France, where he met Louis Braille. Braille identified the major failing of the code, which was that the human finger could not encompass the whole symbol without moving and so could not move rapidly from one symbol to another. His modification was to use a six-dot cell, the Braille system that revolutionized written communication for the visually impaired. Night writing Night writing, a.k.a. sonography, was a system of code that used symbols of twelve dots arranged as two columns of six dots embossed on a square of paperboard, and is now
Read-copy-update "RCU" was one of many contributions by the Linux community. Other names for similar techniques include "passive serialization" and "MP defer" by VM/XA programmers and "generations" by K42 and Tornado programmers. Techniques and mechanisms resembling RCU have been independently invented multiple times: Bauer, R.T., (June 2009), "Operational Verification of a Relativistic Program" PSU Tech Report TR-09-04 (http://www.pdx.edu/sites/www.pdx.edu.computer-science/files/tr0904.pdf) Read-copy-update In computer science, read-copy-update (RCU) is a synchronization mechanism based on mutual exclusion. It is used when performance of reads is crucial and is an example of space–time tradeoff, enabling fast operations at the cost of more space. Read-copy-update allows multiple threads