Device File
In Unix almost all things are handled as files and have a location in the file system — even hardware devices like hard drives. The great exception for devices and the files that represent them are network devices that do not turn up in the file system but are handled separately.
Device files are used to apply access rights and to direct operations on the files to the appropriate device drivers.
Unix makes a distinction between character devices and block devices. The distinction is roughly as follows:
- character devices provide only a serial stream of input or output;
- block devices are randomly accessible;
although, for example, disk partitions may have both character devices that provide unbuffered random access to blocks on the partition and block devices that provide buffered random access to blocks on the partition.
A character device is marked with a c as the first letter of the mode string. Likewise, a block device is marked with a b, e.g.
Read more about this topic: Unix File Types
Famous quotes containing the words device and/or file:
“UG [universal grammar] may be regarded as a characterization of the genetically determined language faculty. One may think of this faculty as a ‘language acquisition device,’ an innate component of the human mind that yields a particular language through interaction with present experience, a device that converts experience into a system of knowledge attained: knowledge of one or another language.”
—Noam Chomsky (b. 1928)
“While waiting to get married, several forms of employment were acceptable. Teaching kindergarten was for those girls who stayed in school four years. The rest were secretaries, typists, file clerks, or receptionists in insurance firms or banks, preferably those owned or run by the family, but respectable enough if the boss was an upstanding Christian member of the community.”
—Barbara Howar (b. 1934)