News Server Operation - Spools

Spools

When the server stores the body of an article, it places it in a disk storage area generically called a "spool". There are several common ways in which the spool may be organized:

  • One file per article is the oldest storage scheme, still in common use on smaller servers and replicated in many clients. Its performance capability is a direct function of the underlying operating system's ability to create, remove and locate files within a directory, and often this scheme is insufficient to keep up with modern Usenet traffic. It does, however, allow for the greatest flexibility in managing the amount and location of storage used by the server. Nearly all current software using this scheme stores articles using the B News 2.10 layout.
  • Cyclical storage has been in increasingly common use since the 1990s. In this storage method, articles are appended serially to large indexed container files. When the end of the file is reached, new articles are written at the beginning of the file, overwriting the oldest entries. On some servers, this overwriting is not performed, but instead new container files are created as older ones are deleted. The major advantages of this system include predictable storage requirements if an overwriting scheme is employed, and some freedom from dependency on the underlying performance of the operating system. There is, however, less flexibility to retain articles by age rather than space used, and traditional text manipulation tools such as grep are less well suited to analyzing these files. Some degree of article longevity control can be exercised by directing subsets of the newsgroups to specific sets of container files.
  • In some cases, a relational database or similar is used to contain the spool. This is most commonly seen with Internet forum software that also offers an NNTP interface.
  • Some servers, such as INN, allow multiple storage schemes to be used at once. Various hybrid storage schemes have also been used in news servers, including different organizations of the file-per-article method, or smaller containers carrying perhaps 100 articles apiece.

Read more about this topic:  News Server Operation

Other articles related to "spools, spool":

8 Mm Film - Standard 8
... The film spools actually contain a 16 mm film with twice as many perforations along each edge than normal 16 mm film on its first pass through the camera, the film is only exposed along half of its width ... When the first pass is complete, the camera is opened and the spools are flipped and swapped (the design of the spool hole ensures that this happens properly) and the same film ... Common length film spools allowed filming of about 3 minutes to 4.5 minutes at 12, 15, 16 and 18 frames per second ...
Karlsson Spools
... Karlsson Spools AB is a Swedish-based manufacturer of spools for hydraulic valves that are used in hydraulic machinery ... More specifically, the spools are part of directional control valves where the spool slides inside a housing to route hydraulic fluid to mechanical components ... The company manufactures valve spools in sizes ranging between 25–400 mm (1”-16”) length and diameters between 5–50 mm (.120”-2”) ...
Tinkertoy - Standard Parts
... In addition to the previously described spools, a standard Tinkertoy set includes Wheels, which are thinner than spools, but larger in diameter ... Like spools, their center holes have a snug fit ... Pulleys, identical to spools, except that the center holes are loose-fitting ...
Devorah Sperber
... is an American installation artist known for creating works out of spools of thread, chenille pipe cleaners and map tacks that act as optical illusions.Some of ... For example, her creation of the Mona Lisa using spools of thread is titled After The Mona Lisa 2 ... The spools are hung in long, adjacent columns to create a pointillist, inverted abstraction of a famous painting ...
Magnetic Tape Sound Recording - Commercialization - Standardized Products
... Domestic and portable recorders used seven, five or even three inch reels (or spools) ... Early professional machines used single sided spools but double sided spools soon became popular (particularly for domestic use) ... Tape spools were usually made from transparent plastic but metal spools were also used ...