Chorded keyboard (a writing system for the blind) uses either 6 or 8 tactile 'points' from which all letters and numbers are formed. When Louis Braille invented it, it was produced with a needle holing successively all needed points in a cardboard sheet. In 1892, Frank Haven Hall, superintendent of the Illinois Institute for the Education of the Blind, created the Hall Braille Writer, which was like a typewriter with 6 keys, one for each dot in a braille cell. The Perkins Brailler, first manufactured in 1951, uses a 6-key chord keyboard (plus a spacebar) to produce braille output, and has been
Read (system call) errno is set appropriately and further it is left unspecified whether the file position (if any) changes. Read (system call) In modern POSIX compliant operating systems, a program that needs to access data from a file stored in a file system uses the read system call. The file is identified by a file descriptor that is normally obtained from a previous call to open. This system call reads in data in bytes, the number of which is specified by the caller, from the file and stores then into a buffer supplied by the calling process. The read system call takes