In computing, a nibble is a four-bit aggregation, or half an octet. It is known as half-byte or tetrade. In a networking or telecommunication context, the nibble is called a semi-octet, quadbit, or quartet. A nibble has sixteen possible values. A nibble can be called a hex digit. A full byte is represented by two hexadecimal digits. Sometimes the set of all 256 byte values is represented as a 16×16 table, which gives readable hexadecimal codes for each value. Four-bit computer architectures use groups of four bits as their fundamental unit; such architectures were used in pocket calculators and pocket computers. They continue to be used in some microcontrollers. In this context, 4-bit groups were sometimes called characters rather than nibbles; the term'nibble' originates from its representing'half a byte', with'byte' a homophone of the English word'bite'. In 2014, David B. Benson, a professor emeritus at Washington State University, remembered that he playfully used the term nibble as "half a byte" and unit of storage required to hold a binary-coded decimal decimal digit around 1958, when talking to a programmer of Los Alamos Scientific Laboratory.

The alternative spelling'nybble' reflects the spelling of'byte', as noted in editorials of Kilobaud and Byte in the early 1980s. Another early recorded use of the term'nybble' was in 1977 within the consumer-banking technology group at Citibank, it created a pre-ISO 8583 standard for transactional messages between cash machines and Citibank's data centers that used the basic informational unit'NABBLE'. The nibble is used to describe the amount of memory used to store a digit of a number stored in packed decimal format within an IBM mainframe; this technique is used to make computations debugging easier. An 8-bit byte is split in half and each nibble is used to store one decimal digit; the last nibble of the variable is reserved for the sign. Thus a variable which can store up to nine digits would be "packed" into 5 bytes. Ease of debugging resulted from the numbers being readable in a hex dump where two hex numbers are used to represent the value of a byte, as 16×16 = 28. For example, a five-byte BCD value of 31 41 59 26 5C represents a decimal value of +314159265.

There are cases where nybble was used for a group of bits greater than 4. In the Apple II microcomputer line, much of the disk drive control and group-coded recording was implemented in software. Writing data to a disk was done by converting 256-byte pages into sets of 5-bit nibbles and loading disk data required the reverse. Moreover, 1982 documentation for the Integrated Woz Machine refers to an "8 bit nibble"; the term byte once had the same ambiguity and meant a set of bits but not 8, hence the distinction of bytes and octets or of nibbles and quartets. Today, the terms'byte' and'nibble' always refer to 8-bit and 4-bit collections and are rarely used to express any other sizes; the sixteen nibbles and their equivalents in other numeral systems: The terms "low nibble" and "high nibble" are used to denote the nibbles containing the less significant bits and the more significant bits within a byte. In graphical representations of bits within a byte, the leftmost bit could represent the most significant bit, corresponding to ordinary decimal notation in which the digit at the left of a number is the most significant.

In such illustrations the four bits on the left end of the byte form the high nibble, the remaining four bits form the low nibble. For example, ninety-seven = 9710 = 2 = 61hexthe high nibble is 01102, the low nibble is 00012; the total value is high-nibble × 1610 + low-nibble. In C: where b must be a variable or constant of an integral data type, only the least-significant byte of b is used. For example, HI_NIBBLE==0xA and LO_NIBBLE==0xB. In Common Lisp: Binary numeral system Syllable Word "Apple Assembly Line". May 1981

Luke Smith (The Sarah Jane Adventures)

Luke Smith is a fictional regular character played by Tommy Knight in the British children's science fiction television series The Sarah Jane Adventures, a spin-off of the long-running series Doctor Who. Luke is a regular character in The Sarah Jane Adventures both in audio adventures, he has appeared in three episodes of Doctor Who: the two-parter "The Stolen Earth"/"Journey's End", the Tenth Doctor's finale episode "The End of Time, Part Two". Within the narrative of the series, Luke is a human archetype, created by alien species the Bane from thousands of DNA samples, who comes to be adopted by the series' heroine, Sarah Jane Smith. Luke is something of a child prodigy, showcasing a remarkable degree of genius but a level of social ineptitude owing to being born in adolescence. Luke Smith is introduced as "the Archetype" in the first episode of The Sarah Jane Adventures, the New Year's Day special "Invasion of the Bane"; the Bane known as Mrs Wormwood creates the Archetype from thousands of samples of DNA taken from visitors touring their Bubble Shock!

Drink factory. This enables the Bane to run tests on an archetypal human. Luke appears to be an ordinary adolescent boy, except for his lack of a navel having been grown rather than gestated and born naturally, he possesses an exceptional eidetic memory. During one tour of the factory, an alarm is set off when visitor Kelsey Hooper's mobile phone disturbs the Bane Mother; the Archetype awakes and proceeds to escape with visitor Maria Jackson and her investigative journalist neighbour, Sarah Jane Smith. After the Bane Mother sends assassins to kill the group, they return to confront the Bane; the Archetype saves the day by recalling an exceptionally long sequence of numbers necessary to trigger an explosion in the Bubble Shock! factory. In the episode's dénouement, Sarah Jane adopts the boy, naming him "Luke Smith", having considered the names "Harry" and "Alistair" after her friends Harry Sullivan and Brigadier Sir Alistair Lethbridge-Stewart, her sentient supercomputer Mr Smith forges and distributes all the necessary paperwork to formalise the adoption.

Sarah Jane reveals to Luke and Maria that she is a former time traveller, having been a companion of the Doctor and lives a dangerous life investigating alien invasions and schemes on Earth. Revenge of the Slitheen sets up Series 1 of The Sarah Jane Adventures, depicting Luke's first day at school and his difficulties and early bonding anxieties with Sarah Jane. Luke struggles to adapt to life at school owing to his inability to lie or master humour and his apparent genius-level intellect which sets him apart from his fellow pupils, he and Maria meet and befriend Clyde Langer, whilst Luke makes an enemy of Carl, an intelligent boy who envies his effortless intellectual superiority. The friends discover that Carl and three members of staff at the school have been replaced by members of the alien Slitheen family from Raxacoricofallapatorius, that Luke has assisted unknowingly their plan to switch off the Sun by providing them with the equation they needed to run the machine that will absorb its energy.

Luke tricks the Slitheen into resetting their machinery and most of the Slitheen are trapped in their secret room in the school and explode. Luke and Maria assist Sarah Jane against alien Gorgons in their second adventure, the war-faring alien Uvodni in their third. A plot by extra-dimensional villain the Trickster erases both Luke and his mother from history in the story Whatever Happened to Sarah Jane?, although Maria restores it in the second part. Sarah Jane is forced to give Luke up in series finale The Lost Boy when a couple allege that Luke is their biological son, casting doubts on his original origin; this transpires to be a plot by the original Slitheen that Luke believed he had killed, who attempt to harness Luke's latent psychic abilities to telekinetically bring the Moon crashing into the Earth. Luke and Sarah Jane are reunited. Luke is mentioned, but does not appear, in the Doctor Who Series 4 episode "Turn Left", wherein a plot by the Trickster created an alternate reality where the Doctor is dead.

Luke, Sarah Jane and Maria die in an alternate version of the Doctor Who episode "Smith and Jones". Subsequently, the Doctor Who Series 4 finale features Luke, Sarah Jane, Mr Smith and robot dog K9 witness a Dalek invasion of Earth. With Earth having been transported across space for use in the Daleks' "Reality Bomb", Luke assists the Tenth Doctor and his associates, through web conferencing, in using the TARDIS in conjunction with Mr Smith and the Cardiff Rift to tow Earth back to its rightful place. Following this, Series 2 of The Sarah Jane Adventures sees Luke part ways with Maria when she moves to America in The Last Sontaran, befriend investigative new girl Rani Chandra who comes to discover the extraterrestrial activities that he, Clyde and his mother are involved with in The Day of the Clown. In the Series 2 serial, The Temptation of Sarah Jane Smith, Luke meets his grandparents in a time travel plot set up by the Trickster. In Series 3's The Mad Woman in the Attic, an alien shows Luke a vision of the future in which he appears to be graduating from university at a young age.

He meets the Doctor in person for the first time in The Wedding of Sarah Jane Smith and assists him in defeating the Trickster for a third time. Luke is absent from the two-

Sandra Finan

Sandra E. Finan was the Deputy Chief Information Officer for Command, Control and Computers and Information Infrastructure Capabilities, Office of the Secretary of Defense, Washington D. C. Finan entered the Air National Guard in 1982 as an enlisted cryptographic equipment repairperson, she received her Air Force commission in 1985 as a distinguished graduate through Officer Training School. During her career, Finan has served in a variety of space and missile assignments in missile crew operations, she has held staff assignments as executive assistant to the Director of Security and Emergency Operations with the Department of Energy, National Military Command System command and control officer at U. S. Strategic Command, she has served on the 20th Air Force staff and as a command evaluator at Vandenberg Air Force Base, California Her commands include a space operation squadron and missile wing. Finan has deployed to the Combined Air Operations Center in Southwest Asia as the Director of Space Forces in support of operations Iraqi Freedom and Enduring Freedom.

Prior to her assignment with the Nuclear Weapons Center, she was the Inspector General at Air Force Global Strike Command. Finan retired in 2017 out of her last assignment in Washington DC with the Pentagon. 1978 Bachelor of Arts degree in music education, California State University, San Bernardino, California 1989 Squadron Officer School, Maxwell Air Force Base, Alabama 1989 Master of Science degree in systems management, University of Southern California, Los Angeles, California 1997 Master of Arts degree in national defense and strategic studies, Naval Command and Staff College, Rhode Island 1997 Armed Forces Staff College, Virginia 2004 Master of Strategic Studies degree, Air War College, Maxwell Air Force Base, Alabama 2006 National Security Fellow, Syracuse University, New York November 1982 – January 1985, Air National Guard cryptographic technician and Air Force Reserve military training instructor, Lackland AFB, Texas April 1985 – May 1987, protocol officer and executive officer, 2nd Bombardment Wing, Barksdale AFB, La.

June 1987 – August 1987, undergraduate missile training, Vandenberg AFB, Calif. September 1987 – August 1991, senior evaluator commander and missile combat crew member, 341st Missile Wing, Malmstrom AFB, Mont. September 1991 – September 1993, command operations evaluator, 3901st Missile Evaluation Squadron, Vandenberg AFB, Calif. October 1993 – June 1996, program manager. E. Warren AFB, Wyo. July 1996 – June 1997, Naval Command and Staff College, Newport, R. I. July 1997 – September 1997, Joint Professional Military Education Phase II, Armed Forces Staff College, Norfolk, Va. October 1997 – August 1999, special assistant to the Commander. S. Strategic Command, Offutt AFB, Neb. September 1999 – August 2000, executive assistant to the Director of Security and Emergency Operations, Department of Energy, Washington, D. C. September 2000 – June 2001, operations officer, 21st Space Operation Squadron, Onizuka Air Force Station, Calif. July 2001 – June 2003, Commander, 21st Space Operations Squadron, Installation Commander, Onizuka AFS, Calif.

July 2003 – May 2004, Air War College, Maxwell AFB, Ala. June 2004 – July 2006, Vice Commander, 91st Missile Wing, Minot AFB, N. D. July 2006 – May 2008, Commander, 341st Missile Wing, Malmstrom AFB, Mont. June 2008 – August 2009, Nuclear Operations, Headquarters Air Force Space Command, Peterson AFB, Colo. September 2009 – December 2010, Inspector General, Headquarters Air Force Global Strike Command, Barksdale AFB, La. January 2011 – January 2013, Principal Assistant Deputy Administrator for Military Application, Office of Defense Programs, National Nuclear Security Administration, Department of Energy, Washington, D. C. February 2013 – October 2015, Air Force Nuclear Weapons Center, Kirtland AFB, N. M. October 2015 – present, Deputy Chief Information Officer for Command, Control and Computers and Information Infrastructure Capabilities, Office of the Secretary of Defense, Washington D. C. Media related to Sandra Finan at Wikimedia Commons