A type of program error that requires that the program responsible for the error be shut down. Software applications communicate with operating systems and other applications through layers of code. An exception is an error alert that communicates the problem across the layers. When an error is detected, the exception is sent through the layers of code one by one until code is found that can handle the error. If no code has been included in any layer of the program to handle the specific error, the exception will travel through all the layers, create a fatal exception error, terminate the application and may even shut down the operating system.
For example, a program may request that the operating system reserve a block of memory for the program’s use. If the operating system is unable to honor the request – if the memory request is too large or if there is not enough available memory – it will send a memory exception to the layer that made the request. The exception will continue to travel through the layers until it is dealt with. If the program does not catch the exception, because the programmer did not write code to handle that particular exception, the exception makes its way to the top layer and the operating system recognizes it as an unhandled exception and shuts down the program, resulting in a fatal exception error. Well-designed software, however, handles all exceptions.
- Fault Tolerance
The ability of a system to respond gracefully to an unexpected hardware or software failure. There are many levels of fault tolerance, the lowest being the ability to continue operation in the event of a power failure. Many fault-tolerant computer systems mirror all operations — that is, every operation is performed on two or more […]
(pronounced as separate letters) Short for field-replaceable unit, a generic term used to describe any hardware device, or more commonly a part or component of a device or system, that easily can be replaced by a skilled technician without having to send the entire device or system to be repaired. The name implies that the […]
(v) To send a document via a fax machine. (n) (1) A document that has been sent, or is about to be sent, via a fax machine. (2) Short for Facsimile machine.
- Fax Machine
Short for facsimile machine, a device that can send or receive pictures and text over a telephone line. Fax machines work by digitizing an image — dividing it into a grid of dots. Each dot is either on or off, depending on whether it is black or white. Electronically, each dot is represented by a […]
- fax modem
A device you can attach to a personal computer that enables you to transmit and receive electronic documents as faxes. A fax modem is like a regular modem except that it is designed to transmit documents to a fax machine or to another fax modem. Some, but not all, fax modems do double duty as […]