FA
Failure
Analysis.
Father
In CD manufacturing (mastering), this is the metal master. It is created in the first step of the electroforming process when the nickel coating is removed from the glass master which results in an inverted image of the glass master.
FC
Fiber Channel
FC-AL or Fibre Channel-Arbitrated Loop
It is a serial SCSI Archecture (SSA) protocol that transfers 100 MBps or 200 MBps using a dual loop configuration. Up to 126 devices can be connected to the host adapter; distances are based on the cable used: 30 m using coaxial cable, 100 m via a backplane (copper cable), and a maximum 10 Km with fiber optic cables.
Other references: SSI, SSA-P1394 "FireWire," and SSA-Fiber Channel.
Note: PC What's The Problem? includes signal assignments and functional troubleshooting suggestions.
FCC
Federal Communications Commission
FC-EL
Fibre Channel-Enhanced Loop.
FDDI
Fiber Distributed Data Interface, reference: Fiberoptic cable.
Feed Horn
A satellite antenna or satellite dish's reflective surface gathers and concentrates the satellite's signal to the electronics located in the frontend. There, the Feed Horn gathers the signals and channels them to the LNB amplifier. (The polarity of the satellite signal is selected by the Servo Motor.)
FETs
Field-effect transistors. These are referenced with all
other Transistors.
FEU
A processor chip's Arithmetic Unit's Functions Evaluation Unit which performs common functions, and contains the CGS (Coefficient Generation System) and FM (Functions module). Part of the VMP.
FFT
Fast Fourier Transform.
FGEN
FFT (Fast Fourier Transform) Generator.
FH (or "Full" height)
A standard full-height drive. Also reference: 3H, 4H, and HH.
Fiberoptic cable
As fast as most metal-wire cables, fiberoptic cables can transmit more data, over a longer distance, and without electrical interference "noise." Wire cables transmit electrical current from one component to another. fiberoptic cables transmit signals between components, as pulses of light through thin, flexible glass or plastic fibers, that are smaller in size and lighter in weight than metal wires. However, optical-fiber connections must be aligned precisely for light to pass from one fiber to another; wire cables only require the connectors to touch.
A fiberoptic cable consists of a light-conducting core made of silica glass or plastic, and an outer coating called "cladding" which keeps the light inside the core by reflecting it back into and along the core. The bouncing, flowing movement of the light through the core is called multi-mode. Light that passes straight through the core is termed: mono-mode.
Multi-mode fibers have less capacity, slower data transmission speed and less bandwidth than mono-mode fibers. Multi-mode fibers require light-repeaters to maintain the integrity of the light pulses over long distances. Mono-mode fibers do not require repeaters; however, multi-mode fibers are less expensive and easier to install. Most LANs use multi-mode fibers with a uniform "step-index," (the difference between the light refractive index of the fiber core and the cladding is step-like). Not all optical-fiber cables have fibers with the same core diameter; AT&T specifies 62.5 microns, IBM uses 100 microns&emdash;clearly incompatible.
Fiber Distributed Data Interface (FDDI) ANSI-formulated standard specifies a fiber core diameter of 62.5 microns and 125 microns for the cladding. It also specifies a maximum of 1,000 physical connections (500 stations), and a total length of 200 km.
Most LAN fiberoptical cables transmit light in only one direction; two cables are enclosed in an outer jacket, one for each direction. However, there are single-cable two-way full-duplex LANs like Pure Data ARCnet. Optical-fibers must be well formed (without scratches or dents) and pure (without glass chips or foreign mater) which might diffuse or scatter light pulses. Both ends of the cable have polished surfaces that permit light to shine through without distortion.
Generally, the ends of optical-fibers are then glued into precision-formed connectors. Most cables have Dust Caps for protection until they are installed. To transmit digital signals, pulses of light are used to represent: 1s, the gaps between pulses represent: 0s. (On, off.)
"Rise-time" is how long it takes a light source to generate a full-power pulse; faster power rises- and falls-per-second results in an increased number of bits-per second of transmission.
Light Emitting Diodes (LEDs) are less expensive than lasers, and have acceptable rise-times for powering LANs. At the receiving end of the cable, solid-state photoreceptors are used to detect the pulses of light.
Fiberoptic LANs (FO-LANs), in general, for PC-based FO-LANs, fiberoptic cable links can exceed 3.5 km. This is 15 times the distance of twisted-pair cables, and 11 times that of coaxial cables. However, the design of some LAN-access protocols often limit the overall length of cables. For example, in an Ethernet LAN; the distance between two nodes may be limited to 2.5 km (1.5 miles).
Installing optical-fiber cables with pre-attached connectors is no more difficult than installing twisted-pair or coax cables. However, hands-on training is required for cutting fibers and for attaching connectors to them. Cable installation requires some skill in reading diagrams. Planning every step is necessary because it is wiser to use cables of sufficient length for each segment of the installation than to add extensions, or reduce cable length.
Note: PC What's The Problem? includes installation, test, and repair suggestions.
FIFO
First In First Out.
File Transfer - Basic Capture
When a file is received, this protocol directs it to the system's RAM and then to disk storage. No interactive "handshaking" controls are sent between systems. Other file transfer references: File Transfer - Basic Send, Full-Feature File Transfer, Remote File Transfer, and Unattended-Remote File Transfer.
Note: PC What's The Problem? includes functional troubleshooting suggestions.
File Transfer - Basic Send
This protocol provides for sending a file (usually in ASCII format), by its file name and disk storage address, to a remote system. You see the file on your display screen as it is transferred. The receiving system sends the file to its display screen as it arrives. To store the received file, the remote system's communication software must be set for "basic capture," before transmission, or the file will be lost. No interactive "handshaking" controls are sent between systems.
Other file transfer references: File Transfer - Basic Capture, Full-Feature File Transfer, Remote File Transfer, and Unattended-Remote File Transfer.
Note: PC What's The Problem? includes functional troubleshooting suggestions.
Firewall
A network "server" computer--intended to protect a network of connected computers, including other servers, from unauthorized access.
FireWire or SSA-P 1394
Up to 63 FireWire devices (including computers) can be networked in a chain at-the-same-time; however, a star-network configuration cannot exceed 8 cables, nor two linked stars together exceed 16 cables (including the cable between them). FireWire does not support a ring-network; unused connections should be left empty. Termination is unnecessary.
The original specifications transmitted data at 12.5 MegaBytes per second (MBps). Subsequent revisions went to 80 MBps., then to 100, 200, and currently an isochronous data rate of 400 MBps can be achieved. It has the potential to exceed 1.2 GBps. Each 1394 bus can have a maximum 72 m of cables with no more than 4.5 m between each device/node. (Bridges can expand this network.) Virtually any device can be connected (drives, camcorders, air conditioners, lights, etc.). This bus automatically initializes itself when it is powered on and whenever a device/node is added or removed&emdash;even with the power on. This is a "hot pluggable," Auto ID (configuration) capability. A half-duplex packet bus, 1394 automatically arbitrates between asynchronous and isochronous (time-dependent) transmissions, setting fair intervals, so that all devices waiting to send data get a chance to do so.
Interface boards with FireWire interfaces are compatible with PCI-bus, PPC (PowerPC chip) systems using MacOS 7.6 (or later version) and the FireWire Support extension file.
Other references: IEE-1394, SSI, SSA-Fiber Channel, and Fiber Channel-A.
Note: PC What's The Problem? includes installation and testing suggestions.
Flash RAM
Flash SIMMs are nonvolital; data isn't lost when there is no power, it can be maintained for 10 years or longer. Flash RAM is programable, it can be pre-loaded with a BIOS, an operating system, or application-specific support codes. The industry standard is an 80-pin module. Mostly, they are used in printers and communications devices.
Most Flash modules are single-voltgage; an external voltage source for programing and erase operations need not be present, eliminating the need for extra taps on a powersupply. A Flash module must be matched to the powersupply; for example, a 5-V-only, a 2.7-V-only (that works from 2.7 V to 3.6 V), a 2.5 V and a 1.6 V. However, there are many Flash module designs. Flash modules with flexible voltages usually support user-programing; one manufacturer makes modules with read voltage options of 3.3 V and 2.7 V, a 5-V-only read-write and a fast write 12-V capability.
Flash PC Cards
These PC (PCMCIA-bus) cards use Flash RAM chips in a Type 1 package. Early flash cards supported dual-voltage sources; for example, 5 V for reading and 12 V for writing data. Recent Flash PC cards have single-voltage (5 V, 3.3 V, read-write PC cards have been Developed to act like a hard disk, this RAM is completely non-volatile and data may be safely stored in it for years. Note: PC What's The Problem includes functional troubleshooting suggestions.
Floptical
Flexible magneto-optical "MO drives" merge magnetic data-storage media, as used in floppy disks, with the data-storage capacity advantages of CDs. The laser read/write mechanism is more compact and precise than the heads used in hard drives; bits can be recorded closer together on the media. These drives have either two lasers, one for erasing and one for recording, or a single laser that does both: heating the track to be recorded while applying a magnetic field to reorient all magnetism in the same direction (to errase all data) then recording new data during a second rotation.
Compare this two-step writing process to the single-step magnetic field modulation-overwriting of the read/write heads in conventional floppy drives. Sony's MiniDisc (MD DATA) storage drives accomplishes this single-step process. Another reference: MD.
Firewall
A network "server" computer--intended to protect a network of connected computers, including other servers, from unauthorized access.
4H (or "fourth" )
A drive or bay within a computer case that is one-fourth the size of the standard full height. Also reference: FH, 3H, and HH.
FM
Frequency Modulation.
FM
A processor chip's Functions module. A part of the Functions Evaluation Unit (FEU).
Format
The arrangement or layout of information on C/DVD media.
FP-EDO-DRAM Fast-page EDO DRAM.
FP-DRAM
Fast-page DRAM (Dynamic RAM) chips.
FPLP
Power-limited Fire Alarm Plenum cable.
FPU
A Floating-Point Unit is a math coprocessors found in many personal computers. The Intel 80387 is one example of an FPU. FPUs perform certain calculations faster than CPUs because they specialize in floating-point math, whereas CPUs are geared for integer math. Many CPU's have the FPU integrated into their circuitry rather than packaged and sold separately. See also CPU.
FP-EDO-DRAM
Fast-page EDO DRAM.
FP-DRAM
Fast-page Dynamic RAM chips.
FPGA
Field-programmable Gate Aray.
FQFP
Fine-pitch quad flat-pack.
FRAM
Ferroelectric RAM chips are nonvolatile devices which can retain data for a 10 year minimum without any backup power. They are used in IC identity and validation cards. A FRAM IC card can rewrite data as many as 10 billion times, compared with 100 thousand times for EEPROM-based IC cards.
FRAME
A Video Frame is the data (or time) required for one
complete picture, i.e., 1/30 of a second for the NTSC
standard.
A CD Frame is 1/75 of a second in length and contains 2352 bytes. Video frames are not related to CD frames.
FRAMM
Foldable Ridged Assembly Memory Module was developed by Dynamem Inc. for use in laptop computers and systems with few SIMM slots. These memory modules are composed of two TSOP (thin small-outline package) cards attached at the top with a rigid hinge.
The (128 MB) 72-pin arrangement has a bottom card that looks like a SIMM and plugs into a SIMM slot. Its chips are on one side. The second (top?) card has its chips on the opposite side as those on the bottom card; when folded over, these chips appear to be inside.
The (256M MB) 168-pin arrangement links two dual-sided DIMM-type cards.
Note: PC What's The Problem? includes identification, test, repair and replacement suggestions.
Frequency
The "clock" crystal on a computer's systemboard sets the frequency of signals passing in the circuit between each component and the microprocessor (or CPU). It determines the specific number of commands that the CPU can process within a specific time frame.
Frequency Modulation
A type of data transmission, in which pulses are sent more frequently&emdash;and therefore data is sent faster&emdash;than Alternating Electrical Current.
Frequency Shift Keying (FSK)
A method of signal modulation, FSK transmits a digital-data bit as either a "low-frequency" pulse (0), or a "high-frequency" pulse (1). Bell 103 and 212A-type modems send both digits at lower relative frequencies than they receive. (Sometimes they are received, lower to higher, higher to lower). Also reference: Combining Modulations.
FRD and FRD+
Failure Resistant Disk Systems, reference: RAB.
FTAM
File Transfer Access Method, a standard set by the ISO for transferring files between computers with different operating systems.
FTDS and FTDS+
Failure Tolerant Disk Systems, reference: RAB.
Full Duplex
Two way communications, at the same time. This protocol lets either system interrupt the other one's transmissions.
Full-Feature File Transfer
The receiving system (through "handshaking" with the sending system), controls the file transfer process. The sending system requests permission to transfer the file. There is no "echo" of the file to either the sender's or receiver's screen. (Echoes would cause delays in the transfer.) Among the many other features are: setting the number of times the software will try to send the file after detecting an error; filtering outgoing and/or incoming data; translating outgoing and/or incoming data.
Other file transfer references: File Transfer - Basic Capture, File Transfer - Basic Send, Remote File Transfer, and Unattended-Remote File Transfer.
Note: PC What's The Problem? includes functional troubleshooting suggestions.
F/V
Frequency-to-voltage.
References are samples only. Each one is presented in greater detail in the
Technical Research Assistant for 2001
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