In computing, bit numbering is the convention used to identify the bit positions in a binary number or a container of such a value. The bit number is incremented by one for each subsequent bit position. In computing, the least significant bit is the bit position in a binary integer giving the units value, that is, determining whether the number is or odd; the LSB is sometimes referred to as the low-order bit or right-most bit, due to the convention in positional notation of writing less significant digits further to the right. It is analogous to the least significant digit of a decimal integer, the digit in the ones position, it is common to assign each bit a position number, ranging from zero to N-1, where N is the number of bits in the binary representation used. This is the exponent for the corresponding bit weight in base-2. Although a few CPU manufacturers assign bit numbers the opposite way, the term least significant bit itself remains unambiguous as an alias for the unit bit. By extension, the least significant bits are the bits of the number closest to, including, the LSB.
The least significant bits have the useful property of changing if the number changes slightly. For example, if 1 is added to 3, the result will be 4 and three of the least significant bits will change. By contrast, the three most significant bits stay unchanged. Least significant bits are employed in pseudorandom number generators, steganographic tools, hash functions and checksums. In digital steganography, sensitive messages may be concealed by manipulating and storing information in the least significant bits of an image or a sound file. In the context of an image, if a user were to manipulate the last two bits of a color in a pixel, the value of the color would change at most +/- 3 value places, to be indistinguishable by the human eye; the user may recover this information by extracting the least significant bits of the manipulated pixels to recover the original message. This allows for the transfer of digital information to be kept concealed. LSB can stand for least significant byte; the meaning is parallel to the above: it is the byte in that position of a multi-byte number which has the least potential value.
If the abbreviation's meaning least significant byte isn't obvious from context, it should be stated explicitly to avoid confusion with least significant bit. To avoid this ambiguity, the less abbreviated terms "lsbit" or "lsbyte" may be used. In computing, the most significant bit is the bit position in a binary number having the greatest value; the MSB is sometimes referred to as the high-order bit or left-most bit due to the convention in positional notation of writing more significant digits further to the left. The MSB can correspond to the sign bit of a signed binary number in one's or two's complement notation, "1" meaning negative and "0" meaning positive, it is common to assign each bit a position number ranging from zero to N-1 where N is the number of bits in the binary representation used. This is the exponent for the corresponding bit weight in base-2. Although a few CPU manufacturers assign bit numbers the opposite way, the MSB unambiguously remains the most significant bit; this may be one of the reasons why the term MSB is used instead of a bit number, although the primary reason is that different number representations use different numbers of bits.
By extension, the most significant bits are the bits closest to, including, the MSB. MSB can stand for "most significant byte"; the meaning is parallel to the above: it is the byte in that position of a multi-byte number which has the greatest potential value. To avoid this ambiguity, the less abbreviated terms "MSbit" or "MSbyte" are used; this table illustrates an example of decimal value of 149 and the location of LSB. In this particular example, the position of unit value is located in bit position 0. MSB stands for Most Significant Bit. Position of LSB is independent of how the bit position is transmitted, a question more of a topic of Endianness; the expressions Most Significant Bit First and Least Significant Bit First are indications on the ordering of the sequence of the bits in the bytes sent over a wire in a transmission protocol or in a stream. Most Significant Bit First means that the most significant bit will arrive first: hence e.g. the hexadecimal number 0x12, 00010010 in binary representation, will arrive as the sequence 0 0 0 1 0 0 1 0.
Least Significant Bit First means that the least significant bit will arrive first: hence e.g. the same hexadecimal number 0x12, again 00010010 in binary representation, will arrive as the sequence 0 1 0 0 1 0 0 0. When the bit numbering starts at zero for the least significant bit the numbering scheme is called "LSB 0"; this bit numbering method has the advantage that for any unsigned number the value of the number can be calculated by using exponentiation with the bit number and a base of 2. The value of an unsigned binary integer is therefore ∑ i = 0 N − 1 b i ⋅ 2 i where bi denotes the value of the bit w
"Hello, World!" program
A "Hello, World!" program is a computer program that outputs or displays the message "Hello, World!". Because it is simple in most programming languages, it is used to illustrate the basic syntax of a programming language and is the first program that those learning to code write. A "Hello, World!" program is traditionally used to introduce novice programmers to a programming language. "Hello, world!" is traditionally used in a sanity test to make sure that a computer language is installed, that the operator understands how to use it. While small test programs have existed since the development of programmable computers, the tradition of using the phrase "Hello, world!" as a test message was influenced by an example program in the seminal book The C Programming Language. The example program from that book prints "hello, world", was inherited from a 1974 Bell Laboratories internal memorandum by Brian Kernighan, Programming in C: A Tutorial: The C version was preceded by Kernighan's own 1972 A Tutorial Introduction to the Language B, where the first known version of the program is found in an example used to illustrate external variables: main a'hell'.
The phrase is divided into multiple variables because in B, a character constant is limited to four ASCII characters. The previous example in the tutorial printed hi! on the terminal, the phrase hello, world! was introduced as a longer greeting that required several character constants for its expression. The Jargon File claims that hello, world originated instead with BCPL; this claim is supported by the archived notes of the inventors of BCPL, Prof. Brian Kernighan at Princeton and Martin Richards at Cambridge. For modern languages, world programs vary in sophistication. For example, the Go programming language introduced a multilingual program, Sun demonstrated a Java hello, world based on scalable vector graphics, the XL programming language features a spinning Earth hello, world using 3D graphics. While some languages such as Perl, Python or Ruby may need only a single statement to print "hello, world", a low-level assembly language may require dozens of commands. Mark Guzdial and Elliot Soloway have suggested that the "hello, world" test message may be outdated now that graphics and sound can be manipulated as as text.
There are many variations on the punctuation and casing of the phrase. Variations include the presence or absence of the comma and exclamation mark, the capitalization of the'H', both the'H' and the'W', or neither; some languages are forced to implement different forms, such as "HELLO WORLD", on systems that support only capital letters, while many "hello, world" programs in esoteric languages print out a modified string. For example, the first non-trivial Malbolge program printed "HEllO WORld", this having been determined to be good enough. There are variations in spirit, as well. Functional programming languages, like Lisp, ML and Haskell, tend to substitute a factorial program for Hello, World, as functional programming emphasizes recursive techniques, whereas the original examples emphasize I/O, which violates the spirit of pure functional programming by producing side effects. Languages otherwise capable of Hello, World may be used in embedded systems, where text output is either difficult or nonexistent.
For devices such as microcontrollers, field-programmable gate arrays, CPLD's, "Hello, World" may thus be substituted with a blinking LED, which demonstrates timing and interaction between components. The Debian and Ubuntu Linux distributions provide the "hello, world" program through the apt packaging system. While of itself useless, it serves as a sanity check and a simple example to newcomers of how to install a package, it is more useful for developers, however, as it provides an example of how to create a.deb package, either traditionally or using debhelper, the version of hello used, GNU Hello, serves as an example of how to write a GNU program. Time to "Hello World" is a metric for how long it takes to get a "Hello World" program running from scratch in a given programming language. "99 Bottles of Beer" as used in computer science Foobar Java Pet Store Just another Perl hacker List of basic computer science topics Trabb Pardo-Knuth algorithm List of hello world programs at Wikibooks Rösler, Wolfram.
"Hello World Collection". Helloworldcollection.de. "Hello world/Text". Rosetta Code. "Unsung Heroes of IT / Part One: Brian Kernighan". TheUnsungHeroesOfIT.com. Archived from the original on 2016-03-26. Retrieved 2014-08-23
Charles David George "Charlie" Stross is a British writer of science fiction, Lovecraftian horror, fantasy. Stross specialises in hard science space opera. Between 1994 and 2004, he was an active writer for the magazine Computer Shopper and was responsible for the monthly Linux column, he stopped writing for the magazine to devote more time to novels. However, he continues to publish freelance articles on the Internet. Stross was born in England, he showed an early interest in writing and wrote his first science fiction story at age 12. He graduated with a bachelor's degree in Pharmacy in 1986 and qualified as a pharmacist in 1987. In 1989, he enrolled at Bradford University for a post-graduate degree in computer science. In 1990, he went to work as programmer. In 2000, he began working as a writer full-time, as a technical writer at first, but became successful as a fiction writer. In the 1970s and 1980s, Stross published some role-playing game articles about Advanced Dungeons & Dragons in White Dwarf magazine.
Some of his creatures, such as the death knight, githyanki and slaad were published in the Fiend Folio monster compendium. His first published short story, "The Boys", appeared in Interzone in 1987. A collection of his short stories, Toast: And Other Rusted Futures, was released in 2002, his first novel, Singularity Sky, was published by Ace Books in 2003 and was nominated for the Hugo Award. His novella "The Concrete Jungle" won the Hugo award for its category in 2005, his novel Accelerando won the 2006 Locus Award for best science fiction novel, was a finalist for the John W. Campbell Memorial Award for Best Science Fiction Novel, was on the final ballot for the Hugo Award in the best novel category. Glasshouse won the 2007 Prometheus Award and was on the final ballot for the Hugo Award in the best novel category, his novella "Missile Gap" won the 2007 Locus Award for best novella, most he was awarded the Edward E. Smith Memorial Award or Skylark at Boskone 2008, his novel The Atrocity Archives focused on a British intelligence agency investigating Mythos-like horrors.
I hadn't heard of Delta Green when I wrote The Atrocity Archive... I'll leave it at that except to say that Delta Green has come dangerously close to making me pick up the dice again.""Rogue Farm," his 2003 short story, was adapted into an eponymous animated film that debuted in August 2004. Stross was one of the Guests of Honour at Orbital 2008, the British National Science Fiction convention, in March 2008, he was the Author Guest of Honour at the Maryland Regional Science Fiction Convention in May 2009. He was Author Guest of Honour at Fantasticon in August 2009, he was the Guest of Honor at Boskone 48 in Feb 2011. Cubicle 7 used their Basic Role-Playing license to create The Laundry, based on Stross' writings, wherein agents must deal with the outer gods and British bureaucracy at the same time. In September 2012, Stross released The Rapture of the Nerds, a novel written in collaboration with Cory Doctorow; the two have together been involved in the Creative Commons licensing and copyright movement.
In December 2017 he gave a talk at 34C3. Accelerando won the 2006 Locus Award for Best Science Fiction Novel. "Missile Gap" won the 2007 Locus Award for best novella. "The Concrete Jungle" won the Hugo Award for best novella in 2005. The Apocalypse Codex won the 2013 Locus Award for Best Fantasy Novel. Stross's work has been nominated for a number of other awards, including the John W. Campbell Memorial Award, Arthur C. Clarke Award, the Hugo Award for Best Novel, as well as the Japanese Seiun Award; the Family Trade The Hidden Family The Clan Corporate The Merchants' War The Revolution Business The Trade of Queens Empire Games Dark State Invisible Sun The Atrocity Archives The Jennifer Morgue Down on the Farm Overtime The Fuller Memorandum The Apocalypse Codex Equoid The Rhesus Chart The Annihilation Score The Nightmare Stacks The Delirium Brief The Labyrinth Index Accelerando Halting State Rule 34 Official website – featuring a blog with guest contributions "Stross at Livejournal". Archived from the original on 3 December 2012.
Stross software releases – latest, 2000 Charles Stross at the Internet Speculative Fiction Database Charles Stross at Library of Congress Authorities, with 24 catalogue records "Charles Stross:: Pen & Paper RPG Database". Archived from the original on 10 March 2005. Retrieved 24 November 2018
The SPARCstation 1, or Sun 4/60, is the first of the SPARCstation series of SPARC-based computer workstations sold by Sun Microsystems. It had a distinctive slim enclosure and was first sold in April 1989, with Sun's support for it ending in 1995. Based on a LSI Logic RISC CPU running at 20 MHz, with a Weitek 3170 FPU coprocessor it was the fourth Sun computer to use the SPARC architecture and the first of the sun4c architecture; the motherboard offered three SBus slots and had built-in AUI ethernet, 8 kHz audio, a 5 MB/s SCSI-1 bus. The basic display ran at 1152×900 in 256 colours, monitors shipped with the computer were 16 to 19 inch greyscale or colour. Designed for ease of production to compete with high-end PCs or Macs, it sold for between about US$9,000, to US$20,000 — and in the first year around 35,000 units were sold; the SPARCstation 1 features several distinctive design and packaging elements driven internally by system designer Andy Bechtolsheim and externally by design house frogdesign.
Bechtolsheim specified that the motherboard would be the size of a sheet of paper and the SBus expansion cards would be the size of index cards, resulting in an compact footprint. The external design motif includes dot-patterned cooling vents on the side which are echoed by a "dimple" pattern on the front face, "Sun purple" feet; the SPARCstation 1 takes 30 pin SIMMs in groups of four. It can take 4 MB SIMMs as long as the size is consistent within a bank. There are a total of four memory banks; the memory bank nearest the floppy disk drive should be filled first. If not, the OpenBoot firmware will hang while memory checking; the SPARCstation 1 has space for one floppy drive internally. The machine will take any 50 pin SCSI-2 hard drive, but the OpenBoot firmware will not boot from any partition which starts or ends after 1024 MB; the floppy drive, like the Macintosh's, is unusual in that it has an electromechanical eject mechanism rather than the conventional eject button, therefore must be ejected by the operating system or OpenBoot.
The machine can connect to any SCSI CD drive, via either the SCSI connector on the back or by connecting it to any spare internal SCSI connector via a 50 pin cable. The SPARCstation 1 comes with an on-board AMD Lance ethernet chipset and a 15-pin AUI connector, which can connect to 10Base2, 10Base5 or 10BaseT via an appropriate transceiver; the OpenBoot ROM is able to boot from network, using RARP and TFTP. Like all other SPARCstation systems, the SPARCstation 1 holds system information such as MAC address and serial number in NVRAM. If the battery on this chip dies the system will not be able to boot; the SPARCstation 1 uses an M48T02 battery-backed RTC with RAM chip which handles the real time clock and boot parameter storage. The only problem with this chip is that the battery is internal, which means the entire chip must be replaced when its battery runs out; as all SPARCstation 1s made are now older than the battery life of this chip, a substantial number of these systems now refuse to boot.
Additionally, the SPARCstation 1 design used the reserved bits in the M48T02's NVRAM in a non-standard way. Due to incompatibilities with modern M48T02s, it is common to modify failed NVRAMs by cutting into the encapsulation and patching in a new battery, it is possible to replace the entire encapsulation, which contains a 32.768 KHz clock crystal. The SPARCstation 1, 1+, IPC and SLC can run the following operating systems: SunOS 4.0.3c through 5.7 Linux NetBSD 1.0 onwards OpenBSD - All versions up to 5.9 Four or five SPARCstation 1 units were used by Game Freak to develop Pokémon Red and Green. The SPARCstation 1+ pushed the CPU to a 25 MHz LSI L64801, upgraded the coprocessor to a Weitek 3172 and installed a new SCSI controller; the SPARCstation IPC is a version of the SPARCstation 1 + in onboard video. The SPARCstation SLC is a version of the SPARCstation 1+ built into a monitor cabinet; the SPARCstation 2 is the machine's successor and was released in 1990. SUN NVRAM FAQ OpenBoot command reference at the Wayback Machine Sun 4c class machine handbook at the Wayback Machine
Don Woods (programmer)
Don Woods is an American perennial hacker and computer programmer. He is best known for his role in the development of the Colossal Cave Adventure game. Woods teamed with James M. Lyon while both were attending Princeton in 1972 to produce the unprecedented, excursive INTERCAL programming language, he worked at the Stanford AI lab, where among other things he became the SAIL contact for, a contributor to, the Jargon File. He co-authored "The Hacker's Dictionary" with Mark Crispin, Raphael Finkel, Guy L. Steele Jr. Woods discovered the Colossal Cave Adventure game by accident on a SAIL computer in 1976. After contacting the original author by the means of sending an e-mail to crowther@sitename, where sitename was every host listed on ARPANET, he heard back from William Crowther shortly afterward. Given the go-ahead, Woods proceeded to add enhancements to the Adventure game, distributed it on the Internet, it became popular with users of the PDP-10. Woods stocked the Kentucky cave that Crowther had written with new magical items and geographical features.
Crowther's game, which featured few supernatural elements, was transformed into a loose fantasy world featuring elements from role playing games. Woods can thus, in a sense, be considered one of the progenitors of the entire genre of computer adventure games and interactive fiction. By 1977 tapes of the game were common on the Digital user group DECUS, others. Don Woods' web page Interview with Woods regarding Adventure Computerworld Interview with Don Woods on INTERCAL
GitHub is a web-based hosting service for version control using Git. It is used for computer code, it offers all of the distributed version control and source code management functionality of Git as well as adding its own features. It provides access control and several collaboration features such as bug tracking, feature requests, task management, wikis for every project. GitHub offers plans for enterprise, team and free accounts which are used to host open-source software projects; as of January 2019, GitHub offers unlimited private repositories to all plans, including free accounts. As of June 2018, GitHub reports having over 28 million users and 57 million repositories, making it the largest host of source code in the world. GitHub was developed by Chris Wanstrath, P. J. Hyett, Tom Preston-Werner and Scott Chacon using Ruby on Rails, started in February 2008; the company, GitHub, Inc. is located in San Francisco. On February 24, 2009, GitHub team members announced, in a talk at Yahoo! headquarters, that within the first year of being online, GitHub had accumulated over 46,000 public repositories, 17,000 of which were formed in the previous month alone.
At that time, about 6,200 repositories had been forked at least. On July 5, 2009, GitHub announced. On July 27, 2009, in another talk delivered at Yahoo!, Preston-Werner announced that GitHub had grown to host 90,000 unique public repositories, 12,000 having been forked at least once, for a total of 135,000 repositories. On July 25, 2010, GitHub announced. On April 20, 2011, GitHub announced. On June 2, 2011, ReadWriteWeb reported that GitHub had surpassed SourceForge and Google Code in total number of commits for the period of January to May 2011. On July 9, 2012, Peter Levine, general partner at GitHub investor Andreessen Horowitz, stated that GitHub had been growing revenue at 300% annually since 2008 "profitably nearly the entire way". On January 16, 2013, GitHub announced it had passed the 3 million users mark and was hosting more than 5 million repositories. On December 23, 2013, GitHub announced. In June 2015, GitHub opened an office in Japan, its first office outside of the U. S. On July 29, 2015, GitHub announced it had raised $250 million in funding in a round led by Sequoia Capital.
The round valued the company at $2 billion. In 2016, GitHub was ranked No. 14 on the Forbes Cloud 100 list. On February 28, 2018, GitHub fell victim to the second largest distributed denial-of-service attack in history, with incoming traffic reaching a peak of about 1.35 terabits per second. On June 4, 2018, Microsoft announced it had reached an agreement to acquire GitHub for US$7.5 billion. The purchase closed on October 26, 2018. On June 19, 2018, GitHub expanded its GitHub Education by offering free education bundles to all schools. On June 4, 2018, Microsoft announced its intent to acquire GitHub for US$7.5 billion, the deal closed on Oct. 26, 2018. GitHub will continue to operate independently as a community and business. Under Microsoft, the service will be led by Xamarin's Nat Friedman, reporting to Scott Guthrie, executive vice president of Microsoft Cloud and AI. Current CEO Chris Wanstrath will be retained as a "technical fellow" reporting to Guthrie. Microsoft had become a significant user of GitHub, using it to host open source projects and development tools such as Chakra Core, PowerShell, Visual Studio Code, has backed other open source projects such as Linux, developed Git Virtual File System—a Git extension for managing large-scale repositories.
GitHub, Inc. was a flat organization with no middle managers. Employees can choose to work on projects. However, salaries are set by the chief executive. In 2014, GitHub, Inc. introduced a layer of middle management. GitHub.com was a start-up business, which in its first years provided enough revenue to be funded by its three founders and start taking on employees. In July 2012, four years after the company was founded, Andreessen Horowitz invested $100 million in venture capital. In July 2015 GitHub raised another $250 million of venture capital in a series B round. Investors were Andreessen Horowitz, Thrive Capital and other venture capital funds; as of August 2016, GitHub was making $140 million in Annual Recurring Revenue. GitHub's m
Sun Microsystems, Inc. was an American company that sold computers, computer components and information technology services and created the Java programming language, the Solaris operating system, ZFS, the Network File System, SPARC. Sun contributed to the evolution of several key computing technologies, among them Unix, RISC processors, thin client computing, virtualized computing. Sun was founded on February 24, 1982. At its height, the Sun headquarters were in Santa Clara, California, on the former west campus of the Agnews Developmental Center. On April 20, 2009, it was announced; the deal was completed on January 27, 2010. Sun products included computer servers and workstations built on its own RISC-based SPARC processor architecture, as well as on x86-based AMD Opteron and Intel Xeon processors. Sun developed its own storage systems and a suite of software products, including the Solaris operating system, developer tools, Web infrastructure software, identity management applications. Other technologies included the Java platform and NFS.
In general, Sun was a proponent of open systems Unix. It was a major contributor to open-source software, as evidenced by its $1 billion purchase, in 2008, of MySQL, an open-source relational database management system. At various times, Sun had manufacturing facilities in several locations worldwide, including Newark, California. However, by the time the company was acquired by Oracle, it had outsourced most manufacturing responsibilities; the initial design for what became Sun's first Unix workstation, the Sun-1, was conceived by Andy Bechtolsheim when he was a graduate student at Stanford University in Palo Alto, California. Bechtolsheim designed the SUN workstation for the Stanford University Network communications project as a personal CAD workstation, it was designed around the Motorola 68000 processor with an advanced memory management unit to support the Unix operating system with virtual memory support. He built the first ones from spare parts obtained from Stanford's Department of Computer Science and Silicon Valley supply houses.
On February 24, 1982, Vinod Khosla, Andy Bechtolsheim, Scott McNealy, all Stanford graduate students, founded Sun Microsystems. Bill Joy of Berkeley, a primary developer of the Berkeley Software Distribution, joined soon after and is counted as one of the original founders; the Sun name is derived from the initials of the Stanford University Network. Sun was profitable from its first quarter in July 1982. By 1983 Sun was known for producing 68k-based systems with high-quality graphics that were the only computers other than DEC's VAX to run 4.2BSD. It licensed the computer design to other manufacturers, which used it to build Multibus-based systems running Unix from UniSoft. Sun's initial public offering was in 1986 for Sun Workstations; the symbol was changed in 2007 to JAVA. Sun's logo, which features four interleaved copies of the word sun in the form of a rotationally symmetric ambigram, was designed by professor Vaughan Pratt of Stanford; the initial version of the logo was orange and had the sides oriented horizontally and vertically, but it was subsequently rotated to stand on one corner and re-colored purple, blue.
In the dot-com bubble, Sun began making much more money, its shares rose dramatically. It began spending much more, hiring workers and building itself out; some of this was because of genuine demand, but much was from web start-up companies anticipating business that would never happen. In 2000, the bubble burst. Sales in Sun's important hardware division went into free-fall as customers closed shop and auctioned high-end servers. Several quarters of steep losses led to executive departures, rounds of layoffs, other cost cutting. In December 2001, the stock fell to the 1998, pre-bubble level of about $100, but it kept falling, faster than many other tech companies. A year it had dipped below $10 but bounced back to $20. In mid-2004, Sun closed their Newark, California and consolidated all manufacturing to Hillsboro, Oregon. In 2006, the rest of the Newark campus was put on the market. In 2004, Sun canceled two major processor projects which emphasized high instruction-level parallelism and operating frequency.
Instead, the company chose to concentrate on processors optimized for multi-threading and multiprocessing, such as the UltraSPARC T1 processor. The company announced a collaboration with Fujitsu to use the Japanese company's processor chips in mid-range and high-end Sun servers; these servers were announced on April 17, 2007, as the M-Series, part of the SPARC Enterprise series. In February 2005, Sun announced the Sun Grid, a grid computing deployment on which it offered utility computing services priced at US$1 per CPU/hour for processing and per GB/month for storage; this offering built upon an existing 3,000-CPU server farm used for internal R&D for over 10 years, which Sun marketed as being able to achieve 97% utilization. In August 2005, the first commercial use of this grid was announced for financial risk simulations, launched as its first software as a service product. In January 2005, Sun reported a net profit of $19 million for fiscal 2005 second quarter, for the first time in three years.
This was followed by net loss of $9 million on GAAP basis for the third quarter 2005, as reported on April 14, 2005. In January 2007, Sun reported a net GAAP profit of $126