Josh References Glossary F

fast file system (FFS)
The first major revision to the Unix file system, providing faster read access and faster (delayed, asynchronous) write access through a disk cache and better file system layout on disk. See also file system.

See File Allocation Table (FAT).

See Fiber Channel (FC).

See Fiber Distributed Data Interface (FDDI).

See Forward Explicit Congestion Notification (FECN).

See fast file system (FFS).

Fiber Channel (FC)
A high-speed networking standard for disks whose underlying medium is fiber optics.

Fiber Distributed Data Interface (FDDI)
A high-speed networking standard (RFC 1285 and RFC 1512) whose underlying medium is fiber optics. The topology is dual-attached, counter-rotating Token Ring.

field-replacable unit (FRU)
A hardware component that can be replaced in the field, as opposed to at the factory.

See first in, first out (FIFO).

File Allocation Table (FAT)
A table that the operating system on a personal computer uses to locate files on a disk. Due to fragmentation, a file may be divided into many sections that are scattered around the disk. The FAT keeps track of all these pieces. See also superblock.

file system
A hierarchical structure of data on one or more disks or partitions. The actual structural details depend on the file system type. See Andrew File System (AFS), Common Internet File System (CIFS), distributed file system (DFS), Fast File System (FFS), Hierarchical File System (HFS), Institutional File System (IFS), Network File System (NFS), and Unix File System (UFS).

File Transfer Protocol (FTP)
A TCP/IP protocol (RFC 959) specifying the transfer of text or binary files across the network.

A logical or physical discontinuity in a network to prevent unauthorized access to data or resources. See also external firewall.

See first in, last out (FILO).

first in, first out (FIFO)
A method of queue management where the first item in is the first item out, much like a grocery store line. See also queue.

first in, last out (FILO)
A method of queue management where the first item in is the last item out, much like a stack of papers. See also stack.

Forward Explicit Congestion Notification (FECN)
A bit in the Frame Relay header that is set when the network router has detected congestion in the destination direction (or "foreward," from the packet's point of view). See also Backward Explicit Congestion Notification (BECN).

See fully qualified domain name (FQDN).

A partial block of data on disk (fragment). Typically there are 8 frags per block. The smallest frag is equal to a sector.

Storing files noncontiguously on a disk. Fragmentation increases the time it takes to read a file since the disk has to rotate more and the disk read heads have to seek more.

frame relay
A low-level network transport similar to Asynchronous Transfer Mode (ATM) wherein frames or packets are relayed from one switch to another.

(Security.) Describes the interrelationships between different parts of a program or organization.

free list
A list of unallocated blocks and inodes kept in the superblock.

See field-replacable unit (FRU).

See File Transfer Protocol (FTP).

fully qualified domain name (FQDN)
A host specification including the entire domain structure complete to the top-level domain (.com, .edu, .mil, and so on), in format.