Technical data

subnet
An organization of hosts within a network into logical groups. A network can
be comprised of several subnets. The portion of a network, which might be a
physically independent network, that shares a network address with other portions
of the network and is distinguished by a subnet number. A subnet is to a network
what a network is to an internet.
subnet address
A part of the Internet addressing scheme. If a site uses a single IP address for
multiple physical networks, there is one subnet address for each physical network.
Each such address is composed of the network part of the full address and part
of the local part (host).
subnet field
A bit field in an IP address that denotes the subnet number. The bits making up
this field are not necessarily contiguous in the address.
subnet mask
A method of representing the portion of the IP network address that is devoted to
subnet address. Each bit that is turned on (binary one) in the mask is interpreted
as part of the network and subnet address. Synonymous with network mask.
See address mask.
superuser
A UNIX user who has been granted special privileges; has an effective UID of 0.
symbiont
A process that transfers record-oriented data to and from a mass storage device; for
example, from disks to printers.
Synonym for daemon.
symbolic link
In the UNIX file system, a symbolic link is a file that contains a pointer to another
file or directory. The link (also called a soft link) may be created across a different
UNIXfilesystem.Anychangestothefilecanbeseenwhenyouaccessthefile
through the file name or through the symbolic link. If you delete the file, the
symbolic link will point to a nonexistent file.
synchronous transmission
Data transmission in which characters are transmitted at a fixed rate. The
transmitter and receiver are synchronized, gaining greater efficiency than in
asynchronous transmission. Synchronous transmissions send a predetermined
group of "sync" characters ahead of a long stream of data. The sync characters
enable the communicating devices to synchronize with each other in accordance
with a time clock at each end. Contrast with asynchronous transmission.
syntax
The rules for formatting or interpreting data.
TAC
See terminal access controller.
target system
The intended destination of messages.
TCP
See Transmission Control Protocol.
Glossary–44