Anesthesia and 8b/10b encoding: Difference between pages

Revision as of 13:28, 2 May 2004

Revision as of 15:33, 1 August 2005

Line 1:

In [[telecommunication]]s, '''8B/10B''' is a [[line code]] that maps [[8-bit]] symbols to [[10-bit]] symbols to achieve [[Direct current|DC]] balance and bounded disparity, and yet provide enough state changes to allow reasonable clock recovery. This means that there are just as many "1"s as "0"s in a string of two symbols, and that there are not too many "1"s or "0"s in a row. This is an important attribute in a signal that needs to be sent at high rates because it helps reduce "[[intersymbol interference]]". The code was described in 1983 by Al Widmer and Peter Franaszek in the [[IBM]] Journal of Research and Development. IBM was issued a patent for the scheme the following year.

Anesthesia ([[American English|AE]]) ('''anaesthesia''' [[British English|BE]])is the process of blocking the experience of pain. This allows patients to undergo [[surgery]] without the distress and pain they would otherwise experience. There are two forms of [[anesthesia]]:

* [[general anesthesia]] - with reversible loss of [[consciousness]]

* [[local anesthesia]] - with reversible loss of [[sensation]] in part of the body

As the scheme name suggests, 8 [[bit]]s of data are transmitted as a 10-bit entity called a ''Symbol'', or ''Character''. The low 5 bits of data are encoded into a 6-bit group and the top 3 bits are encoded into a 4-bit group. These code groups are concatenated together to form the 10-bit Symbol that is transmitted on the wire. The ''Data Symbols'' are often referred to as Dxx.y where xx ranges from 0-31 and y from 0-7. Standards using the 8B/10B encoding also define ''Special Symbols'' (or ''Control Characters'') that can be sent in place of a ''Data Symbol''. They are often used to indicate end-of-frame, link idle, skip and similar link-level conditions. They are referred to as Kxx.y and have different encodings from any of the Dxx.y symbols. Because 8B/10B encoding uses 10-bit symbols to encode 8-bit words, each of the 256 possible 8-bit words can be encoded in two different ways, one the bit-wise inverse of the other. Using these alternative encodings, the scheme is able to affect long-term DC-balance in the serial data stream, allowing links to be capacitively coupled.

[[Medicine|Medical]] doctors specialising in the administration of [[anesthetic]]s are known as [[anesthesiologist]]s in American English and as [[anaesthetist]]s in British English.

The encoding is normally done entirely in hardware based on lookup tables. Upper levels of the software stack should be unaware that this encoding is being used.

=== History ===

The first [[herbalism|herbal]] anaesthesia was administered in [[prehistory]]. [[Opium]] and [[hemp]] were two of the most important herbs used. They were ingested or burned and the smoke inhaled. In [[China]], [[Taoist]] medical practitioners developed anaesthesia by means of [[acupuncture]].

Among the areas in which 8B/10B encoding finds application are [[Fibre Channel]], [[Gigabit Ethernet]], [[InfiniBand]], [[XAUI]], and audio storage devices such as the [[Digital Audio Tape]] and [[Digital Compact Cassette]] (DCC). The related [[Eight-to-Fourteen Modulation]] is used in the [[Compact Disc]] standard. The encoding scheme used in [[10 Gigabit Ethernet]]'s 10GBASE-R [[Physical Media Dependent]] (PMD) interfaces, 64B/66B, while similarly created with consideration of DC balance, maximum run length, transition density, electromagnetic emissions, and the like, is considerably different in design.

The modern era of anaesthesia began when the anaesthetic qualities of [[nitrous oxide]] were discovered by the British chemist [[Sir Humphry Davy]] about [[1800]]. This [[gas]] was used in [[1844]] for painless tooth extraction by American [[dentist]] [[Horace Wells]]. On [[March 30]], [[1842]] in [[Jefferson, Georgia]], Dr. [[Crawford Williamson Long]] was the first to use anaesthesia during an operation; [[ether]] was given to his wife during childbirth. Five years later, in [[1847]], [[Sir James Simpson]] discovered the anaesthetic use of [[chloroform]].

==External Linkslinks==

*[http://domino.research.ibm.com/tchjr/journalindex.nsf/0/b4e28be4a69a153585256bfa0067f59a?OpenDocument Original paper by Franaszek and Widmer].

* [http://www.histansoc.org.uk/ History of Anaesthesia society]

*[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/search-bool.html&r=1&f=G&l=50&co1=AND&d=ptxt&s1=4486739.WKU.&OS=PN/4486739&RS=PN/4486739 US Patent 4,486,739], the relevant document at the US Patent and Trademark Office's site.

* [http://con.kolivas.net/ A medical student's guide to anaesthesia from a patient's perspective]

* [http://www.gasnet.org/ Gasnet], a comprehensive online resource on anaesthesiology

* [http://www.asahq.org/ American Society of Anaesthesiologists]

* [http://www.oyston.com/anaes/ Patient's guides and more anaesthesia-related information]

* [http://www.bartleby.com/65/ac/acupunct.html Columbia Encyclopedia-Acupuncture]

* [http://www.taima.org/en/opium.htm Opium in Japan]

* [http://www.taima.org/en/medical.htm Medical Uses of Marijuana]

* [http://www.library.ucla.edu/libraries/biomed/his/painexhibit/index.html University of California Pain Alleviation and Anesthesia Exhibit]

* [http://www.anesthesia-nursing.com/ether.html The Unusual History of Ether]

* [http://neurosurgery.mgh.harvard.edu/History/ether3.htm Conquering surgical pain: Four men stake their claim]

* [http://www.hmcnet.harvard.edu/anesthesia/history/vandam.html A History of Anaesthesia at Harvard University]

[[Category:Computer and telecommunication standards]]

{{msg:Medicine}}

[[Category:Line codes]]

[[defr:AnaesthesieEncodage 8b/10b]]

[[sv:Anestesi]]

[[zh:麻醉學]]