System V printing system

The printing subsystem of UNIX System V is one of several standardized systems for printing on Unix, and is typical of commercial System V-based Unix versions such as Solaris and SCO OpenServer. A system running this print architecture could traditionally be identified by the use of the user command lp as the primary interface to the print system, as opposed to the BSD lpr command (though some systems provide lpr as an alias to lp).

Typical user commands available to the System V printing system are:

History

In the Unix programming model, device files are special files that act as access points to peripheral devices such as printers. For example, the first line printer on a Unix system might be represented by a file lp1 in the device (/dev) directory, i.e., /dev/lp1. Using the file metaphor, a document could by printed by "copying" the file onto the device: cp document /dev/lp1. While this worked well enough for the case where there was one printer per user, this model did not scale out well to multiple users having to share one printer. The solution was to create a queue (or "spool") of documents to be printed and use a daemon (system process) to manage this queue and send the documents to the printer in the order in which they arrived.

LP record

The LP (long play), or 33 ¹⁄₃ rpm microgroove vinyl record, is a format for phonograph (gramophone) records, an analog sound storage medium. Introduced by Columbia Records in 1948, it was soon adopted as a new standard by the entire record industry. Apart from relatively minor refinements and the important later addition of stereophonic sound capability, it has remained the standard format for vinyl albums.

Format advantages

At the time the LP was introduced, nearly all phonograph records for home use were made of an abrasive (and therefore noisy) shellac compound, employed a much larger groove, and played at approximately 78 revolutions per minute (rpm), limiting the playing time of a 12-inch diameter record to less than five minutes per side. The new product was a 12- or 10-inch (30 or 25 cm) fine-grooved disc made of vinyl and played with a smaller-tipped "microgroove" stylus at a speed of 33 ¹⁄₃ rpm. Each side of a 12-inch LP could play for more than 20 minutes. Only the microgroove standard was truly new, as both vinyl and the 33 ¹⁄₃ rpm speed had been used for special purposes for many years, as well as in one unsuccessful earlier attempt to introduce a long-playing record for home use.

Durango Rock Shelters Archeology Site

Durango Rock Shelters Archeology Site is also known as the Fall Creek Rock Shelters Site. An Ancient Pueblo People (Anasazi) archaeological site, it is located in Durango in La Plata County, Colorado. People from the Late Basketmaker II and Basketmaker III Eras inhabited the site between AD 0 and AD 1000.

The site is also known as "5LP4134".

Discovery

Earl H. Morris conducted an excavation of this open talus site in Animas Valley in 1938-1939. It was the first site where dwellings had been found of the early Basketmakers with actual house structures, one of which he describes as follows:

See also

References

External links