Home About us Products Services Contact us Bookmark
:: wikimiki.org ::
Supercomputer

Supercomputer

A supercomputer is a computer that leads the world in terms of processing capacity, particularly speed of calculation, at the time of its introduction. (The term Super Computing was first used by New York World newspaper in 1920 to refer to the large custom built tabulators IBM had made for Columbia University.) Supercomputers introduced in the 1960s were designed primarily by Seymour Cray at Control Data Corporation (CDC), and led the market into the 1970s until Cray left to form his own company, Cray Research. He then took over the supercomputer market with his new designs, holding the top spot in supercomputing for 5 years (1985–1990). In the 1980s a large number of smaller competitors entered the market, in a parallel to the creation of the minicomputer market a decade earlier, but many of these disappeared in the mid-1990s "supercomputer market crash". Today, supercomputers are typically one-of-a-kind custom designs produced by "traditional" companies such as IBM and HP, who had purchased many of the 1980s companies to gain their experience, although Cray Inc. still specializes in building supercomputers. Cray Inc. The term supercomputer itself is rather fluid, and today's supercomputer tends to become tomorrow's also-ran. CDC's early machines were simply very fast scalar processors, some ten times the speed of the fastest machines offered by other companies. In the 1970s most supercomputers were dedicated to running a vector processor, and many of the newer players developed their own such processors at lower price points to enter the market. The early and mid-1980s saw machines with a modest number of vector processors working in parallel become the standard. Typical numbers of processors were in the range 4–16. In the later 1980s and 1990s, attention turned from vector processors to massive parallel processing systems with thousands of "ordinary" CPUs; some being off the shelf units and others being custom designs. Today, parallel designs are based on "off the shelf" RISC microprocessors, such as the PowerPC or PA-RISC, and most modern supercomputers are now highly-tuned computer clusters using commodity processors combined with custom interconnects.

Software tools

Software tools for distributed processing include standard APIs such as MPI and PVM, and open source-based software solutions such as Beowulf and openMosix which facilitate the creation of a sort of "virtual supercomputer" from a collection of ordinary workstations or servers. Technology like ZeroConf (Rendezvous/Bonjour) pave the way for the creation of ad hoc computer clusters. An example of this is the distributed rendering function in Apple's Shake compositing application. Computers running the Shake software merely need to be in proximity to each other, in networking terms, to automatically discover and use each other's resources. While no one has yet built an ad hoc computer cluster that rivals even yesteryear's supercomputers, the line between desktop, or even laptop, and supercomputer is beginning to blur, and is likely to continue to blur as built-in support for parallelism and distributed processing increases in mainstream desktop operating systems. An easy programming language for supercomputers remains an open research topic in Computer Science.

Uses

Supercomputers are used for highly calculation-intensive tasks such as weather forecasting, climate research (including research into global warming), molecular modeling (computing the structures and properties of chemical compounds, biological macromolecules, polymers, and crystals), physical simulations (such as simulation of airplanes in wind tunnels, simulation of the detonation of nuclear weapons, and research into nuclear fusion), cryptanalysis, and the like. Military and scientific agencies are heavy users.

Design

Supercomputers traditionally gained their speed over conventional computers through the use of innovative designs that allow them to perform many tasks in parallel, as well as complex detail engineering. They tend to be specialized for certain types of computation, usually numerical calculations, and perform poorly at more general computing tasks. Their memory hierarchy is very carefully designed to ensure the processor is kept fed with data and instructions at all times—in fact, much of the performance difference between slower computers and supercomputers is due to the memory hierarchy. Their I/O systems tend to be designed to support high bandwidth, with latency less of an issue, because supercomputers are not used for transaction processing. As with all highly parallel systems, Amdahl's law applies, and supercomputer designs devote great effort to eliminating software serialization, and using hardware to accelerate the remaining bottlenecks.

Supercomputer challenges, technologies


- A supercomputer generates large amounts of heat and must be cooled. Cooling most supercomputers is a major HVAC problem.
- Information cannot move faster than the speed of light between two parts of a supercomputer. For this reason, a supercomputer that is many meters across must have latencies between its components measured at least in the tens of nanoseconds. Seymour Cray's supercomputer designs attempted to keep cable runs as short as possible for this reason: hence the cylindrical shape of his famous Cray range of computers.
- Supercomputers consume and produce massive amounts of data in a very short period of time. According to Ken Batcher, "A supercomputer is a device for turning compute-bound problems into I/O-bound problems." Much work on external storage bandwidth is needed to ensure that this information can be transferred quickly and stored/retrieved correctly. Technologies developed for supercomputers include:
- Vector processing
- Liquid cooling
- Non-Uniform Memory Access (NUMA)
- Striped disks (the first instance of what was later called RAID)
- Parallel filesystems

Processing techniques

Vector processing techniques were first developed for supercomputers and continue to be used in specialist high-performance applications. Vector processing techniques have trickled down to the mass market in DSP architectures and SIMD processing instructions for general-purpose computers. Modern video game consoles in particular use SIMD extensively and this is the basis for some manufacturers' claim that their game machines are themselves supercomputers. Indeed, some graphics cards indeed have the computing power of several TeraFLOPS However, their uses are very limited.

Operating systems

Supercomputer operating systems, today most often variants of UNIX, are every bit as complex as those for smaller machines, if not more so. Their user interfaces tend to be less developed however, as the OS developers have limited programming resources to spend on non-essential parts of the OS (i.e., parts not directly contributing to the optimal utilization of the machine's hardware). This stems from the fact that because these computers, often priced at millions of dollars, are sold to a very small market, their R&D budgets are often limited. Interestingly this has been a continuing trend throughout the supercomputer industry, with former technology leaders such as Silicon Graphics taking a backseat to such companies as NVIDIA, who have been able to produce cheap, feature rich, high-performance, and innovative products due to the vast number of consumers driving their R&D. Historically, until the early-to-mid-1980s, supercomputers usually sacrificed instruction set compatibility and code portability for performance (processing and memory access speed). For the most part, supercomputers to this time (unlike high-end mainframes) had vastly different operating systems. The Cray-1 alone had at least six different proprietary OSs largely unknown to the general computing community. Similarly different and incompatible vectorizing and parallelizing compilers for Fortran existed. This trend would have continued with the ETA-10 were it not for the initial instruction set compatibility between the Cray-1 and the Cray X-MP, and the adoption of UNIX operating system variants (such as Cray's UniCOS). For this reason, in the future, the highest performance systems are likely to have a UNIX flavor but with incompatible system unique features (especially for the highest end systems at secure facilities).

Programming

The parallel architectures of supercomputers often dictate the use of special programming techniques to exploit their speed. Special-purpose Fortran compilers can often generate faster code than the C or C++ compilers, so Fortran remains the language of choice for scientific programming, and hence for most programs run on supercomputers. To exploit the parallelism of supercomputers, programming environments such as PVM and MPI for loosely connected clusters and OpenMP for tightly coordinated shared memory machines are being used.

Types of general-purpose supercomputers

There are three main classes of general-purpose supercomputers:
- Vector processing machines allow the same (arithmetical) operation to be carried out on a large amount of data simultaneously.
- Tightly connected cluster computers use specially developed interconnects to have many processors and their memory communicate with each other, typically in a NUMA architecture. Processors and networking components are engineered from the ground up for the supercomputer. The fastest general-purpose supercomputers in the world today use this technology.
- Commodity clusters use a large number of commodity PCs, interconnected by high-bandwidth low-latency local area networks. As of 2005, Moore's Law and economies of scale are the dominant factors in supercomputer design: a single modern desktop PC is now more powerful than a 15-year old supercomputer, and at least some of the design tricks that allowed past supercomputers to out-perform contemporary desktop machines have now been incorporated into commodity PCs. Furthermore, the costs of chip development and production make it uneconomical to design custom chips for a small run and favor mass-produced chips that have enough demand to recoup the cost of production. Additionally, many problems carried out by supercomputers are particularly suitable for parallelization (in essence, splitting up into smaller parts to be worked on simultaneously) and, particularly, fairly coarse-grained parallelization that limits the amount of information that needs to be transferred between independent processing units. For this reason, traditional supercomputers can be replaced, for many applications, by "clusters" of computers of standard design which can be programmed to act as one large computer.

Special-purpose supercomputers

Special-purpose supercomputers are high-performance computing devices with a hardware architecture dedicated to a single problem. This allows the use of specially programmed FPGA chips or even custom VLSI chips, allowing higher price/performance ratios by sacrificing generality. They are used for applications such as astrophysics computation and brute-force codebreaking. Examples of special-purpose supercomputers:
- Deep Blue, for playing chess
- Reconfigurable computing machines or parts of machines
- GRAPE, for astrophysics
- Deep Crack, for breaking the DES cipher

The fastest supercomputers today

Measuring supercomputer speed

The speed of a supercomputer is generally measured in "FLOPS" (FLoating Point Operations Per Second); this measurement is based on a particular benchmark, which mimics a class of real-world problems, but is significantly easier to compute than a majority of actual real-world problems.

Current fastest supercomputer system

benchmark On March 25, 2005, IBM's Blue Gene/L prototype became the fastest supercomputer in a single installation using its 32,768 processors to run at 280.6 TFLOPS (1012 FLOPS). The Blue Gene/L prototype is a customized version of IBM's PowerPC architecture. The prototype was developed at IBM's Rochester, Minnesota facility, but production versions were rolled out to various sites, including Lawrence Livermore National Laboratory (LLNL). On October 28, 2005 the machine reached 280.6 TFLOPS, but the LLNL system is expected to achieve at least 360 TFLOPS, and a future update will take it to 0.5 PFLOPS. Before this, a Blue Gene/L fitted with 131,072 processors managed seven hours of sustained calculating at a 101.5 teraflops—another first. [http://news.bbc.co.uk/1/hi/technology/4386404.stm] In November of 2005 IBM Blue Gene/L became the number 1 on TOP500's most powerful supercomputer list.[http://www.top500.org/lists/2005/11/basic] The Google server farm constitutes one of the most powerful supercomputers in the world.

Previous fastest supercomputer system

Prior to Blue Gene/L, the fastest supercomputer was the NEC Earth Simulator at the Yokohama Institute for Earth Sciences, Japan. It is a cluster of 640 custom-designed 8-way vector processor computers based on the NEC SX-6 architecture (a total of 5,120 processors). It uses a customised version of the UNIX operating system. At the time of introduction, the Earth Simulator's performance was over five times that of the previous fastest supercomputer, the cluster computer ASCI White at Lawrence Livermore National Laboratory. The Earth Simulator held the #1 position for 2½ years. Because it was largely unanticipated by the top performers at the time, its introduction spawned the term "computnik," in a reference to the Soviet Union's upstaging of the Western space program with the 1957 launch of Sputnik. A list of the 500 fastest supercomputer installations, the TOP500, is maintained at http://www.top500.org/ .

Quasi-supercomputing

Some types of large-scale distributed computing for embarrassingly parallel problems take the clustered supercomputing concept to an extreme. One such example, the SETI@home distributed computing project has an average processing power of 72.53 TFLOPS [http://setiathome.berkeley.edu/totals.html]. On May 16 2005, the distributed computing project Folding@home reported a processing power of 195 TFLOPS on their CPU statistics page.[http://vspx27.stanford.edu/cgi-bin/main.py?qtype=cpustats]. Still higher powers have occasionally been recorded: on February 2 2005, 207 TFLOPS were noted as coming from Windows, Mac, and Linux clients [http://castlecops.com/t103306-Folding_Home_News.html]. GIMPS distributed Mersenne Prime search achieves currently 18 TFLOPS. Google's search engine system may be faster with estimated total processing power of between 126 and 316 TFLOPS. Tristan Louis estimates the systems to be composed of between 32,000 and 79,000 dual 2 GHz Xeon machines. [http://www.tnl.net/blog/entry/How_many_Google_machines] Since it would be logistically difficult to cool so many servers at one site, Google's system would presumably be another form of distributed computing project: grid computing.

Timeline of supercomputers

Historical and present:

See also

General concepts, history


- Beowulf cluster
- Distributed computing
- Flash mob computer
- Grid computing
- History of computing
- MOSIX
- Parallel computing

Other classes of computer


- Minisupercomputer
- Mainframe computer
- Superminicomputer
- Minicomputer
- Microcomputer

Supercomputer companies, operating

These companies make supercomputer hardware and/or software, either as their sole activity, or as one of several activities.
- Cluster Resources, Inc.
- Cray Inc.
- Fujitsu
- Galactic Computing Corp.
- Groupe Bull (a French company; as of 2005 claims to be building a supercomputer to become the most powerful machine in Europe)
- IBM
- nCUBE
- NEC Corporation
- Supercomputer Systems
- SGI

Supercomputer companies, defunct

These companies have either folded, or do no longer operate in the supercomputer market.
- Control Data Corporation (CDC)
- Convex Computer
- Kendall Square Research
- MasPar Computer Corporation
- Meiko Scientific
- Sequent Computer Systems
- Thinking Machines

External links

Information resources


- [http://www.top500.org/ TOP500 Supercomputer list]
- [http://www.linuxhpc.org/ Linux High Performance Computing and Clustering]
- [http://www.paralogos.com/DeadSuper/Projects.html Dead Supercomputer]
- [http://www.clusterresources.com Cluster Resources]
- [http://www.clusterbuilder.org Cluster Builder]

Supercomputing centers, organizations


- [http://www.hpcx.ac.uk HPCx] UK national supercomputer service operated by EPCC and Daresbury Lab
- [http://www.csar.cfs.ac.uk CSAR] UK national supercomputer service operated by [http://www.mc.manchester.ac.uk Manchester Computing]
- [http://www.hpc-uk.ac.uk HPC-UK] strategic collaboration between the UK's three leading supercomputer centres - Manchester Computing, EPCC and Daresbury Laboratory
- [http://www.sdsc.edu San Diego Supercomputer Center (SDSC)]
- [http://www.teragrid.org Teragrid]
- [http://www.westgrid.ca/support/topics/scheduling.php WestGrid]
- [http://www.tcf.vt.edu/systemX.html VirginiaTech]
- [http://www.irb.hr/en/cir/projects/dcc/00006/ IRB]
- [http://www.sara.nl/userinfo/lisa/usage/batch/index.html SARA]
- [http://www.psc.edu/ Pittsburgh Supercomputing Center] operated by University of Pittsburgh and Carnegie Mellon University.
- [http://www.LinuxHPC.org LinuxHPC.org]

Specific machines, general-purpose


- [http://www.wswinteractive.com/hp/pnnl/default.htm HP announcement of contract to build Linux supercomputer]
- [http://lwn.net/Articles/4759/ Linux NetworkX press release: Linux NetworX to build "largest" Linux supercomputer]
- [http://www.llnl.gov/asci/news/white_news.html ASCI White press release]
- [http://www.hoise.com/primeur/02/articles/weekly/AE-PR-05-02-59.html Article about Japanese "Earth Simulator" computer]
- [http://www.es.jamstec.go.jp/esc/eng/ "Earth Simulator" website (in English)]
- [http://www.nec.com.sg/necsin/hpcs.htm NEC high-performance computing information]
- [http://www.hq.nasa.gov/hpcc/insights/vol6/supercom.htm Superconducting Supercomputer]

Specific machines, special-purpose


- [http://grape.c.u-tokyo.ac.jp/gp/paper/hardpaper.html Papers on the GRAPE special-purpose computer]
- [http://big.gsc.riken.go.jp/SPCtext.htm More special-purpose supercomputer information]
- [http://chimera.roma1.infn.it/apehdoc/apemille/INFN_APEmille.html Information about the APEmille special-purpose computer]
- [http://phys.columbia.edu/~cqft/ Information about the QCDOC project, machines]
- Supercomputer ko:슈퍼 컴퓨터 ms:Superkomputer ja:スーパーコンピュータ

Computer

A computer is a device capable of processing data according to a program — a list of instructions. The data to be processed may represent many types of information including numbers, text, pictures, or sound. Computers can be extremely versatile. In fact, they are universal information processing machines. According to the Church-Turing thesis, a computer with a certain minimum threshold capability is in principle capable of performing the tasks of any other computer, from those of a personal digital assistant to a supercomputer. Therefore, the same computer designs have been adapted for tasks from processing company payrolls to controlling industrial robots. Modern electronic computers also have enormous speed and capacity for information processing compared to earlier designs, and they have become exponentially more powerful over the years (a phenomenon known as Moore's Law). Computers are available in many physical forms. The original computers were the size of a large room, and such enormous computing facilities still exist for specialized scientific computation - supercomputers - and for the transaction processing requirements of large companies, generally called mainframes. Smaller computers for individual use, called personal computers, and their portable equivalent, the notebook computer, are ubiquitous information-processing and communication tools and are perhaps what most non-experts think of as "a computer". However, the most common form of computer in use today is the embedded computer, small computers used to control another device. Embedded computers control machines from fighter planes to digital cameras.

History of computing

Originally, a "computer" was a person who performed numerical calculations under the direction of a mathematician, often with the aid of a variety of mechanical calculating devices from the abacus onward. An example of an early computing device was the Antikythera mechanism, an ancient Greek device for calculating the movements of planets, dating from about 87 BCE. The technology responsible for this mysterious device seems to have been lost at some point. The end of the Middle Ages saw a reinvigoration of European mathematics and engineering, and by the early 17th century a succession of mechanical calculating devices had been constructed using clockwork technology. A considerable number of technologies that would later prove vital for the digital computer were developed in the late 19th and early 20th centuries, such as the punched card and the vacuum tube ((or valve). Charles Babbage was the first to conceptualize and design a fully programmable computer as early as 1837, but due to a combination of the limits of the technology of the time, limited finance, and an inability to resist tinkering with his design (a trait that would in time doom thousands of computer-related engineering projects), the device was never actually constructed in his lifetime. During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated, special-purpose analog computers, which used a direct physical or electrical model of the problem as a basis for computation. These became increasingly rare after the development of the digital computer. A succession of steadily more powerful and flexible computing devices were constructed in the 1930s and 1940s, gradually adding the key features of modern computers, such as the use of digital electronics (invented by Claude Shannon in 1937) and more flexible programmability. Defining one point along this road as "the first computer" is exceedingly difficult. Notable achievements include the Atanasoff Berry Computer, a special-purpose machine that used valve-driven computation and binary numbers; Konrad Zuse's Z machines; the secret British Colossus computer, which had limited programmability but demonstrated that a device using thousands of valves could be made reliable and reprogrammed electronically; and the American ENIAC — the first general purpose machine, but with an inflexible architecture that meant reprogramming it essentially required it to be rewired. The team who developed ENIAC, recognizing its flaws, came up with a far more flexible and elegant design, which has become known as the stored program architecture, which is the basis from which virtually all modern computers were derived. A number of projects to develop computers based on the stored program architecture commenced in the late 1940s; the first of these to be up and running was the Small-Scale Experimental Machine, but the EDSAC was perhaps the first practical version. Valve-driven computer designs were in use throughout the 1950s, but were eventually replaced with transistor-based computers, which were smaller, faster, cheaper, and much more reliable, thus allowing them to be commercially produced, in the 1960s. By the 1970s, the adoption of integrated circuit technology had enabled computers to be produced at a low enough cost to allow individuals to own a personal computer of the type familiar today.

How computers work: the stored program architecture

While the technologies used in computers have changed dramatically since the first electronic, general-purpose, computers of the 1940s, most still use the stored program architecture (sometimes called the von Neumann architecture; as the article describes the primary inventors were probably ENIAC designers J. Presper Eckert and John William Mauchly). The design made the universal computer a practical reality. The architecture describes a computer with four main sections: the arithmetic and logic unit (ALU), the control circuitry, the memory, and the input and output devices (collectively termed I/O). These parts are interconnected by a bundle of wires (a "bus") and are usually driven by a timer or clock (although other events could drive the control circuitry). Conceptually, a computer's memory can be viewed as a list of cells. Each cell has a numbered "address" and can store a small, fixed amount of information. This information can either be an instruction, telling the computer what to do, or data, the information which the computer is to process using the instructions that have been placed in the memory. In principle, any cell can be used to store either instructions or data. The ALU is in many senses the heart of the computer. It is capable of performing two classes of basic operations: arithmetic operations, the core of which is the ability to add or subtract two numbers but also encompasses operations like "multiply this number by 2" or "divide by 2" (for reasons which will become clear later), as well as some others. The second class of ALU operations involves comparison operations, which, given two numbers, can determine if they are equal, and if not, which is bigger. The I/O systems are the means by which the computer receives information from the outside world, and reports its results back to that world. On a typical personal computer, input devices include objects like the keyboard and mouse, and output devices include computer monitors, printers and the like, but as will be discussed later a huge variety of devices can be connected to a computer and serve as I/O devices. The control system ties this all together. Its job is to read instructions and data from memory or the I/O devices, decode the instructions, providing the ALU with the correct inputs according to the instructions, "tell" the ALU what operation to perform on those inputs, and send the results back to the memory or to the I/O devices. One key component of the control system is a counter that keeps track of what the address of the current instruction is; typically, this is incremented each time an instruction is executed, unless the instruction itself indicates that the next instruction should be at some other location (allowing the computer to repeatedly execute the same instructions). Physically, since the 1980s the ALU and control unit have been located on a single integrated circuit called a Central Processing Unit or CPU. The functioning of such a computer is in principle quite straightforward. Typically, on each clock cycle, the computer fetches instructions and data from its memory. The instructions are executed, the results are stored, and the next instruction is fetched. This procedure repeats until a halt instruction is encountered. Larger computers, such as some minicomputers, mainframe computers, servers, differ from the model above in one significant aspect; rather than one CPU they often have a number of them. Supercomputers often have highly unusual architectures significantly different from the basic stored-program architecture, sometimes featuring thousands of CPUs, but such designs tend to be useful only for specialized tasks.

Digital circuits

The conceptual design above could be implemented using a variety of different technologies. As previously mentioned, a stored program computer could be designed entirely of mechanical components like Babbage's. However, digital circuits allow Boolean logic and arithmetic using binary numerals to be implemented using relays - essentially, electrically controlled switches. Shannon's famous thesis showed how relays could be arranged to form units called logic gates, implementing simple Boolean operations. Others soon figured out that vacuum tubes - electronic devices, could be used instead. Vacuum tubes were originally used as a signal amplifier for radio and other applications, but were used in digital electronics as a very fast switch; when electricity is provided to one of the pins, current can flow through between the other two. Through arrangements of logic gates, one can build digital circuits to do more complex tasks, for instance, an adder, which implements in electronics the same method - in computer terminology, an algorithm - to add two numbers together that children are taught - add one column at a time, and carry what's left over. Eventually, through combining circuits together, a complete ALU and control system can be built up. This does require a considerable number of components. CSIRAC, one of the earliest stored-program computers, is probably close to the smallest practically useful design. It had about 2,000 valves, some of which were "dual components", so this represented somewhere between 2 and 4,000 logic components. Vacuum tubes had severe limitations for the construction of large numbers of gates. They were expensive, unreliable (particularly when used in such large quantities), took up a lot of space, and used a lot of electrical power, and, while incredibly fast compared to a mechanical switch, had limits to the speed at which they could operate. Therefore, by the 1960s they were replaced by the transistor, a new device which performed the same task as the tube but was much smaller, faster operating, reliable, used much less power, and was far cheaper. transistor In the 1960s and 1970s, the transistor itself was gradually replaced by the integrated circuit, which placed multiple transistors (and other components) and the wires connecting them on a single, solid piece of silicon. By the 1970s, the entire ALU and control unit, the combination becoming known as a CPU, were being placed on a single "chip" called a microprocessor. Over the history of the integrated circuit, the number of components that can be placed on one has grown enormously. The first IC's contained a few tens of components; as of 2005, modern microprocessors such from AMD and Intel contain over 100 million transistors. Tubes, transistors, and transistors on integrated circuits can be and are used as the "storage" component of the stored-program architecture, using a circuit design known as a flip-flop, and indeed flip-flops are used for small amounts of very high-speed storage. However, few computer designs have used flip-flops for the bulk of their storage needs. Instead, earliest computers stored data in Williams tubes - essentially, projecting some dots on a TV screen and reading them again, or mercury delay lines where the data was stored as sound pulses traveling slowly (compared to the machine itself) along long tubes filled with mercury. These somewhat ungainly but effective methods were eventually replaced by magnetic memory devices, such as magnetic core memory, where electrical currents were used to introduce a permanent (but weak) magnetic field in some ferrous material, which could then be read to retrieve the data. Eventually, DRAM was introduced. A DRAM unit is a type of integrated circuit containing huge banks of an electronic component called a capacitor which can store an electrical charge for a period of time. The level of charge in a capacitor could be set to store information, and then measured to read the information when required.

I/O devices

I/O is a general term for devices that send computers information from the outside world and that return the results of computations. These results can either be viewed directly by a user, or they can be sent to another machine, whose control has been assigned the computer: In a robot, for instance, the controlling computer's major output device is the robot itself. The first generation of computers were equipped with a fairly limited range of input devices. A punch card reader, or something similar, was used to enter instructions and data into the computer's memory, and some kind of printer, usually a modified teletype, was used to record the results. Over the years, a huge variety of other devices have been added. For the personal computer, for instance, keyboards and mice are the primary ways people directly enter information into the computer; and monitors are the primary way in which information from the computer is presented back to the user, though printers, speakers, and headphones are common, too. There is a huge variety of other devices for obtaining other types of input. One example is the digital camera, which can be used to input visual information. There are two prominent classes of I/O devices. The first class is that of secondary storage devices, such as hard disks, CD-ROMs, key drives and the like, which represent comparatively slow, but high-capacity devices, where information can be stored for later retrieval; the second class is that of devices used to access computer networks. The ability to transfer data between computers has opened up a huge range of capabilities for the computer. The global Internet allows millions of computers to transfer information of all types between each other.

Instructions

The instructions interpreted by the control unit, and executed by the ALU, are not nearly as rich as a human language. A computer responds only to a limited number of instructions, but they are well defined, simple, and unambiguous. Typical sorts of instructions supported by most computers are "copy the contents of memory cell 5 and place the copy in cell 10", "add the contents of cell 7 to the contents of cell 13 and place the result in cell 20", "if the contents of cell 999 are 0, the next instruction is at cell 30". All computer instructions fall into one of four categories: 1) moving data from one location to another; 2) executing arithmetic and logical processes on data; 3) testing the condition of data; and 4) altering the sequence of operations. Instructions are represented within the computer as binary code - a base two system of counting. For example, the code for one kind of "copy" operation in the Intel line of microprocessors is 10110000. The particular instruction set that a specific computer supports is known as that computer's machine language. To slightly oversimplify, if two computers have CPUs that respond to the same set of instructions identically, software from one can run on the other without modification. This easy portability of existing software creates a great incentive to stick with existing designs, only switching for the most compelling of reasons, and has gradually narrowed the number of distinct instruction set architectures in the marketplace.

Programs

Computer programs are simply lists of instructions for the computer to execute. These can range from just a few instructions which perform a simple task, to a much more complex instruction list which may also include tables of data. Many computer programs contain millions of instructions, and many of those instructions are executed repeatedly. A typical modern PC (in the year 2005) can execute around 3 billion instructions per second. Computers do not gain their extraordinary capabilities through the ability to execute complex instructions. Rather, they do millions of simple instructions arranged by people known as programmers. In practice, people do not normally write the instructions for computers directly in machine language. Such programming is incredibly tedious and highly error-prone, making programmers very unproductive. Instead, programmers describe the desired actions in a "high level" programming language which is then translated into the machine language automatically by special computer programs (interpreters and compilers). Some programming languages map very closely to the machine language, such as Assembly Language (low level languages); at the other end, languages like Prolog are based on abstract principles far removed from the details of the machine's actual operation (high level languages). The language chosen for a particular task depends on the nature of the task, the skill set of the programmers, tool availability and, often, the requirements of the customers (for instance, projects for the US military were often required to be in the Ada programming language). Computer software is an alternative term for computer programs; it is a more inclusive phrase and includes all the ancillary material accompanying the program needed to do useful tasks. For instance, a video game includes not only the program itself, but also data representing the pictures, sounds, and other material needed to create the virtual environment of the game. A computer application is a piece of computer software provided to many computer users, often in a retail environment. The stereotypical modern example of an application is perhaps the office suite, a set of interrelated programs for performing common office tasks. Going from the extremely simple capabilities of a single machine language instruction to the myriad capabilities of application programs means that many computer programs are extremely large and complex. A typical example is the Firefox web browser, created from roughly 2 million lines of computer code in the C++ programming language; there are many projects of even bigger scope, built by large teams of programmers. The management of this enormous complexity is key to making such projects possible; programming languages, and programming practices, enable the task to be divided into smaller and smaller subtasks until they come within the capabilities of a single programmer in a reasonable period. Nevertheless, the process of developing software remains slow, unpredictable, and error-prone; the discipline of software engineering has attempted, with some partial success, to make the process quicker and more productive and improve the quality of the end product.

Libraries and operating systems

Soon after the development of the computer, it was discovered that certain tasks were required in many different programs; an early example was computing some of the standard mathematical functions. For the purposes of efficiency, standard versions of these were collected in libraries and made available to all who required them. A particularly common task set related to handling the gritty details of "talking" to the various I/O devices, so libraries for these were quickly developed. By the 1960s, with computers in wide industrial use for many purposes, it became common for them to be used for many different jobs within an organization. Soon, special software to automate the scheduling and execution of these many jobs became available. The combination of managing "hardware" and scheduling jobs became known as the "operating system"; the classic example of this type of early operating system was OS/360 by IBM. The next major development in operating systems was timesharing - the idea that multiple users could use the machine "simultaneously" by keeping all of their programs in memory, executing each user's program for a short time so as to provide the illusion that each user had their own computer. Such a development required the operating system to provide each user's programs with a "virtual machine" such that one user's program could not interfere with another's (by accident or design). The range of devices that operating systems had to manage also expanded; a notable one was hard disks; the idea of individual "files" and a hierarchical structure of "directories" (now often called folders) greatly simplified the use of these devices for permanent storage. Security access controls, allowing computer users access only to files, directories and programs they had permissions to use, were also common. Perhaps the last major addition to the operating system were tools to provide programs with a standardized graphical user interface. While there are few technical reasons why a GUI has to be tied to the rest of an operating system, it allows the operating system vendor to encourage all the software for their operating system to have a similar looking and acting interface. Outside these "core" functions, operating systems are usually shipped with an array of other tools, some of which may have little connection with these original core functions but have been found useful by enough customers for a provider to include them. For instance, Apple's Mac OS X ships with a digital video editor application. Not all operating systems provide all of the above functions; operating systems for smaller computers typically provide fewer, such as the highly minimal operating systems for early microcomputers. Embedded computers may have a specialized operating system, or sometimes none at all. Instead, the custom programs written for their task perform all necessary functions that would be performed by an operating system in less specialized roles.

Computer applications

Embedded computer The first electronic digital computers, with their large size and cost, mainly performed scientific calculations, often to support military objectives. The ENIAC was originally designed to calculate ballistics-firing tables for artillery, but it was also used to calculate neutron cross-sectional densities to help in the design of the hydrogen bomb. This calculation, performed in December, 1945 through January, 1946 and involving over a million punch cards of data, showed the design then under consideration would fail. (Many of the most powerful supercomputers available today are also used for nuclear weapons simulations.) The CSIR Mk I, the first Australian stored-program computer, evaluated rainfall patterns for the catchment area of the Snowy Mountains Scheme, a large hydroelectric generation project. Others were used in cryptanalysis, for example the first programmable (though not general-purpose) digital electronic computer, Colossus, built in 1943 during World War II. Despite this early focus of scientific and military engineering applications, computers were quickly used in other areas. From the beginning, stored program computers were applied to business problems. The LEO, a stored program-computer built by J. Lyons and Co. in the United Kingdom, was operational and being used for inventory management and other purposes 3 years before IBM built their first commercial stored-program computer. Continual reductions in the cost and size of computers saw them adopted by ever-smaller organizations. Moreover, with the invention of the microprocessor in the 1970s, it became possible to produce inexpensive computers. In the 1980s, personal computers became popular for many tasks, including book-keeping, writing and printing documents, calculating forecasts and other repetitive mathematical tasks involving spreadsheets. spreadsheet (1989) marked the acceptance of CGI in the visual effects industry.]] As computers have become cheaper, they have been used extensively in the creative arts as well. Sound, still pictures, and video are now routinely created (through synthesizers, computer graphics and computer animation), and near-universally edited by computer. They have also been used for entertainment, with the video game becoming a huge industry. Computers have been used to control mechanical devices since they became small and cheap enough to do so; indeed, a major spur for integrated circuit technology was building a computer small enough to guide the Apollo missions and the Minuteman missile, two of the first major applications for embedded computers. Today, it is almost rarer to find a powered mechanical device not controlled by a computer than to find one that is at least partly so. Perhaps the most famous computer-controlled mechanical devices are robots, machines with more-or-less human appearance and some subset of their capabilities. Industrial robots have become commonplace in mass production, but general-purpose human-like robots have not lived up to the promise of their fictional counterparts and remain either toys or research projects. Robotics, indeed, is the physical expressions of the field of artificial intelligence, a discipline whose exact boundaries are fuzzy but to some degree involves attempting to give computers capabilities that they do not currently possess but humans do. Over the years, methods have been developed to allow computers to do things previously regarded as the exclusive domain of humans - for instance, "read" handwriting, play chess, or perform symbolic integration. However, progress on creating a computer that exhibits "general" intelligence comparable to a human has been extremely slow.

Networking and the Internet

In the 1970s, computer engineers at research institutions throughout the US began to link their computers together using telecommunications technology. This effort was funded by ARPA, and the computer network that it produced was called the ARPANET. The technologies that made the Arpanet possible spread and evolved. In time, the network spread beyond academic and military institutions and became known as the Internet. The emergence of networking involved a redefinition of the nature and boundaries of the computer. In the phrase of John Gage and Bill Joy (of Sun Microsystems), "the network is the computer". Computer operating systems and applications were modified to include the ability to define and access the resources of other computers on the network, such as peripheral devices, stored information, and the like, as extensions of the resources of an individual computer. Initially these facilities were available primarily to people working in high-tech environments, but in the 1990s the spread of applications like email and the World Wide Web, combined with the development of cheap, fast networking technologies like Ethernet and ADSL saw computer networking become ubiquitous almost everywhere. In fact, the number of computers that are networked is growing phenomenally. A very large proportion of personal computers regularly connect to the Internet to communicate and receive information.

Computing professions and disciplines

In the developed world, virtually every profession makes use of computers. However, certain professional and academic disciplines have evolved that specialize in techniques to construct, program, and use computers. Terminology for different professional disciplines is still somewhat fluid and new fields emerge from time to time: however, some of the major groupings are as follows:
- Computer engineering is that branch of electronic engineering devoted to the physical construction of computers and their attendant components.
- Computer science is an academic study of the processes related to computation, such as developing efficient algorithms to perform specific tasks. It has tackled questions as to whether problems can be solved at all using a computer, how efficiently they can be solved, and how to construct efficient programs to compute solutions. A huge array of specialties has developed within computer science to investigate different classes of problem.
- Software engineering concentrates on methodologies and practices to allow the development of reliable software systems while minimizing, and reliably estimating, costs and timelines.
- Information systems concentrates on the use and deployment of computer systems in a wider organizational (usually business) context.
- Many disciplines have developed at the intersection of computers with other professions; one of many examples is experts in geographical information systems who apply computer technology to problems of managing geographical information.

See also


- Computer hardware
- Computability theory
- Computer datasheet
- Computer expo
- Computer science
- Computer types: desktop, laptop, desknote, roll-away computer, embedded computer, cart computer
- Computing
- Computers in fiction
- Digital
- History of computing
- List of computing topics
- Personal computer
- Word processing
- Computer Programming
- Quantum Computer

References


- [http://www.andrew.mallett.net/tech Learn to configure your computer at Andy's Tech Page] category: computer science ja:コンピュータ ko:컴퓨터 ms:Komputer nb:Datamaskin simple:Computer th:คอมพิวเตอร์

New York World&

Unisphere is a 12-story high, spherical stainless steel representation of the Earth. It is located in Flushing Meadows-Corona Park in the Borough of Queens, New York City. The Unisphere, commissioned to celebrate the beginning of the space age, was conceived and constructed as the Theme Symbol of the 1964/1965 New York World's Fair. The Theme of the World's Fair was "Peace Through Understanding" and the Unisphere represented the theme of global interdependence. It was dedicated to "Man's Achievements on a Shrinking Globe in an Expanding Universe." Designed by Gilmore D. Clarke, The Unisphere was donated by the United States Steel Corporation and constructed by that company's American Bridge Division. It's the world’s largest global structure, rising 140 feet and weighing 700,000 pounds. Some sources say the Unisphere weighs 900,000 pounds, a figure which includes the additional weight of its 200-ton inverted tripod base. Built on the structural foundation that supported the 1939/1940 New York World's Fair's Perisphere, Unisphere is centered in a large, circular reflecting pool and is surrounded by a series of water-jet fountains designed to obscure its tripod pedestal. The effect is meant to make Unisphere appear as if it is floating in space. During the Fair, dramatic lighting at night gave the effect of sunrise moving over the surface of the globe. Additionally, the capitals of nations were marked by uniquely designed lights that held four bulbs each. When one would burn out, another would rotate in place so that the bulbs would not have to be changed during the two-year run of the Fair. Both lighting effects are no longer in operation. Perisphere Three large orbit rings of stainless steel encircle Unisphere at various angles. These orbit rings represent the tracks of Yuri Gagarin, the first man in space, John Glenn, the first American to orbit the Earth and Telstar, the first active communications satellite. America was at the height of the Space Age when Unisphere was constructed, and the rings serve as reminders of America's early space achievements. In 1989, the New York City Parks Department announced a multi-million dollar rehabilitation of Flushing Meadows-Corona Park. Among the projects was a complete restoration of the Unisphere. Begun in late 1993 and completed on May 31, 1994, the project included numerous structural repairs and removal of years worth of grime which had accumulated on the steel. The fountains, which had been shut off since the 1970s, were replaced, and new floodlighting was installed. On May 10, 1995, the Unisphere was given official landmark status by the New York City Landmarks Preservation Commission. It is the only officially designated landmark in Flushing Meadows-Corona Park. The Unisphere is the "unofficial" symbol of the Borough of Queens, NY. The Unisphere has been featured in the hit movie Men in Black, as well as the opening credits of the television sitcom The King of Queens. It was also the finishing point of The Amazing Race 1 when Rob & Brennan are the winners.

External links


- http://www.nywf64.com/ the website dedicated to the 1964/1965 New York World's Fair
- [http://maps.google.com/maps?ll=40.746295,-73.845259&spn=0.004324,0.006588&t=k&hl=en Aerial shot]
- [http://www.nyc.gov/html/lpc/downloads/pdf/reports/unisphere.pdf Unisphere Landmark Designation Report (PDF)]
- [http://www.sorabji.com/_/Unisphere Unisphere pictures] Category:New York City landmarks Category:New York City World's Fairs

1920

1920 (MCMXX) is a leap year starting on Thursday (link will take you to calendar)

Events

January


- January 7 - Forces of Russian White admiral Kolchak surrender in Krasnoyarsk.
- January 9 - Britain announces it will build 1,000,000 homes for war veterans. The promise will never be fulfilled in full.
- January 9 - Thousands of onlookers watch as "The Human Fly" George Polley, climbs the New York Woolworth Building. He has reached the 30th floor when a policeman arrests him for climbing without a permit
- January 10 - League of Nations holds its first meeting and ratifies the Treaty of Versailles ending World War I.
- January 15 - Prohibition goes into effect in the United States with the Eighteenth Amendment coming into effect.
- January 16 - Allies demand that the Netherlands extradite the German Kaiser, who has fled there.
- January 19 - The United States Senate votes against joining the League of Nations.
- January 22 - The Australian Country Party is officially formed.
- January 23 - The Netherlands refuses to extradite the German Kaiser.
- January 28 - The Spanish legion is founded and stationed in North Africa to fight rebels in Morocco.
- January 28 - Turkey gives up the Ottoman Empire and all non-Turkish areas.

February


- February 1 - The Royal Canadian Mounted Police begin operations.
- February 2 - Estonia's independence is recognised.
- February 2 - France occupies Memel.
- February 9 - League of Nations gives Spitzbergen to Norway.
- February 10 - Jozef Haller de Hallenburg performs symbolic engagement of Poland with the sea, celebrating restitution of Polish access to open sea.
- February 17 - Woman named Anna Anderson tries to commit suicide in Berlin and is taken to mental hospital, where she claims she is Anastasia.
- February 14 - The League of Women Voters is founded in Chicago, Illinois.
- February 22 - In Emeryville, California, the first dog racing track to employ an imitation rabbit opens.
- February 24 - Adolf Hitler presents his national socialist program in Munich.

March


- March - World's first peaceful establishment of a social democratic government takes place in Sweden. Hjalmar Branting takes over when Nils Edén resigns.
- March 1 - Hungarian Admiral and statesman Miklós Horthy becomes the Regent of Hungary
- March 1 - The United States Railroad Administration returns control of American railroads to its constituent railroad companies.
- March 13-March 17 - Wolfgang Kapp fails in his coup attempt in Germany due to public resistance and a general strike.
- March 15 ? Red Army of Ruhr, communist army 60.000 men strong, formed
- March 19 - US Congress refuses to ratify Versailles Treaty.
- March 23 - Admiral Horthy declares that Hungary is a monarchy without anyone on the throne.
- March 26 - German government asks France for permission to use its own troops against rebellious Ruhr Red Army in the French-occupied area.
- March 26 - The Black and Tans special constables arrive in Ireland
- March 29 - Sir William Robertson, who enlisted in 1877, becomes a field marshal in the British Army, the first man to rise to this rank from private
- March 31 - Government of Ireland Act 1920 is presented in British parliament.

April-May


- April 2 - German army marches to Ruhr to fight Red Ruhr Army.
- April 4 - Jerusalem pogrom of April, 1920 ? Violence between Arabic and Jewish resident in Jerusalem ? governor declares the state of siege
- April 6 - French troops occupy Frankfurt.
- April 6 - The short-lived Far Eastern Republic declared in eastern Siberia
- April 11 - Mexican Revolution - Alvaro Obregon flees from Mexico City during a trial intended to ruin his reputation - he flees to Guerrero where he joins Fortunato Maycotte
- April 19 - Germany and Bolshevist Russia agree to the exchange of prisoners of war.
- April 20 - Alvaro Obregon announces in Chilpancingo that he intends to fight against the rule of Venustiano Carranza
- April 23 - National council in Turkey denounces the government of sultan Mehmed VI and announces a temporary constitution.
- April 24 - Polish-Soviet War: Polish and Ukrainian troops attack Soviet army occupying Ukraine.
- May 2 - The first game of the Negro National League baseball is played in Indianapolis, Indiana.
- May 7 - Polish-Soviet War: Polish troops occupy Kyiv. Ukrainian government returns to the city.
- May 7 - Venustiano Carranza leaves Mexico City in a large train
- May 9 - Alvaro Obregon's troops enter Mexico City
- May 15 - Maria Bochkareva executed in Soviet Union
- May 16 - Referendum in Switzerland is favorable to joining League of Nations.
- May 16 - In Rome, Pope Benedict XV canonizes Joan of Arc as a saint.
- May 17 - French and Belgian troops leave the cities they have occupied in Germany.
- May 17 - First flight of KLM, Dutch air company, from Amsterdam to London.
- May 20 - Venustiano Carranza arrives in San Antonio Tlaxcalantongo. Troops of Rodolfo Herrero attack him at night and shoot him
- May 24 - Venustiano Carranza is buried in Mexico City - all of his mourning allies are arrested. Adolfo de la Huerta is elected provisional president
- May 24 - French president Paul Deschanel falls out of a train and is later found wandering along the railroad track, wearing pajamas.
- May 27 - Thomas Masaryk becomes president of Czechoslovakia.
- May 29 - Great Horncastle flood. 20 people killed.

June-July


- June 4 - Treaty of Trianon, Treaty of Peace between The Allied and Hungary.
- June 12 - Polish-Soviet War: Red Army retakes Kyiv.
- June 13 - The United States Postal Service rules that children may not be sent via parcel post
- June 15 - New border treaty between Germany and Denmark gives northern Schleswig to Denmark.
- June 22 - Greece attacks Turkish troops.
- July 1 - Germany declares its neutrality in the war between Poland and Soviet Russia
- July 2 - Polish-Soviet War: Red Army continues offensive into Poland.
- July 10 - Arthur Meighen becomes Canada's ninth prime minister.
- July 12 - Bolshevist Russia recognizes independent Lithuania.
- July 13 - London County Council bars foreigners from council jobs.
- July 14 - France declares that Faisal I of Syria is deposed and occupies Damascus and Aleppo
- July 17 - Republic of Mirdite proclaimed near Albanian-Serbian border with Yugoslav support
- July 22 - Polish-Soviet War: Poland sues for peace with Bolshevist Russia.
- July 25 - First transatlantic two-way radio broadcast.
- July 26 - Pancho Villa takes over Sabina and contacts de la Huerta to offer his conditional surrender. He signs his surrender in July 28
- July 29 - The United States Bureau of Reclamation begins contruction of the Link River Dam as part of the Klamath Reclamation Project.

August-September


- August 2 - British parliament passes bill to restore order in Ireland, suspending jury trials.
- August 3 - Catholics riot in Belfast.
- August 10 - Ottoman sultan Mehmed VI's representatives signs the Treaty of Sevres.
- August 11 - Bolshevik Russia recognizes independent Estonia and Latvia.
- August 13 - August 25 - Polish-Soviet War: The Red Army is defeated in the Battle of Warsaw.
- August 15 - Town Hall of Templemore, Ireland, is burned down during the riots.
- August 18 - 19th Amendment to US constitution is passed, guaranteeing women's suffrage.
- 19 August-25 August - Second Silesian Uprising, the Poles in Upper Silesia rise against the Germans
- August 20 - The first commercial radio station in the United States, 8MK (WWJ), begins operations in Detroit, Michigan.
- September 4 - La Tercio de Extranjenos, the "Regiment of Foreigners" (modern-day Spanish Legion) inaugurated in Spain
- September 5 - Presidential elections begin in Mexico
- September 8 - Gabriele D'Annunzio declares Fiume a free state.
- September 16 - The Wall Street bombing: a bomb in a horse wagon explodes in front of the J.P.Morgan building in New York City - 39 dead, 400 injured
- September 20 - The first soldier joins the Spanish Legion.
- September 22 - Flying Squad formed in London Metropolitan Police.
- September 29 - First domestic radio sets come to stores in USA – Westinghouse radio costs $10.
- September 29 - Adolf Hitler's makes first public political speech, in Austria.

October-November


- October 9 - Polish troops take Vilnius
- October 10 - In the Carinthian Plebiscite a large part of Carinthia Province votes to become part of Austria rather than of the Yugoslavia.
- October 12 - Polish-Soviet War After Polish army captures Tarnopol, Dubno, Minsk, and Dryssa, the ceasefire is enforced.
- October 18 - Thousands of unemployed demonstrate in London ? 50 injured
- October 26 - Alvaro Obregon is announced elected president of Mexico
- October 27 - League of Nations moves its headquarters to Geneve, Switzerland
- November 2 - Warren G. Harding defeats James M. Cox in the U.S. presidential election, the first national U.S. election in which women have the right to vote.
- November 2 - In the United States, KDKA AM of Pittsburgh, Pennsylvania (owned by Westinghouse) starts broadcasting as a commercial radio station. The first broadcast was the results of the U.S. presidential election, 1920.
- November 11 - Unknown Soldier buried in Westminster Abbey.
- November 15 - In Geneva, the first assembly of the League of Nations is held.
- November 16 - Queensland and Northen Territory Aviation Services (Qantas) is founded by Hudson Fysh and Paul McGinniss.
- November 17 - Council of League of Nations accepts the constitution of Danzig(Gdansk) free state.
- November 21 - Bloody Sunday - British forces open fire on spectators and players during a Football match in Dublin's Croke Park, following the assassinations of 12 British agents.
- November 28 - The Third Cork Brigade Flying Column under Gen. Tom Barry successfully ambush two lorries of British soldiers at Kilmichael ,Co.Cork.

December


- December 1 - Álvaro Obregón becomes president of Mexico.
- December 5 - Referendum in Greece is favorable to reinstatement of monarchy.
- December 11 - Martial law in Ireland.
- December 16 - Finland joins the League of Nations.
- December 16 - 8.6 Richter scale Earthquake causes landslide in Gansu Province, China - 180.000 dead.
- December 23 - United Kingdom and France ratify the border between French-held Syria and British-held Palestine.
- December 25 - Foundation of The Rosicrucian Fellowship's Spiritual Healing Temple "The Ecclesia" at Mount Ecclesia, Oceanside, California (USA).

Undated


- Number of US Americans move to Paris to escape the Prohibition
- France prohibits selling of contraceptives.
- Roman Ungern von Sternberg conquers Urga and declares himself as a ruler of Mongolia.
- Kurd rebellion in Turkey begins.
- Johnny Torrio invites Al Capone to Chicago, Illinois from New York City, New York.
- Bricks of wine are widely sold throughout U.S.

Births

January


- January 1 - Virgilio Savona, Italian singer and songwriter (Quartetto Cetra)
- January 2 - Isaac Asimov, Russian-born author (d. 1992)
- January 3 - Renato Carosone, Italian musician and singer (d. 2001)
- January 5 - Arturo Benedetti Michelangeli, Italian pianist (d. 1995)
- January 6 - Sun Myung Moon, Korean evangelist
- January 6 - John Maynard Smith, English biologist (d. 2004)
- January 6 - Early Wynn, baseball player (d. 1999)
- January 12 - Bill Reid, Canadian artist (d. 1998)
- January 19 - Javier Pérez de Cuéllar, Peruvian United Nations Secretary General
- January 20 - Federico Fellini, Italian film director (d. 1993)
- January 20 - DeForest Kelley, American actor (d. 1999)
- January 20 - John O'Connor, American Catholic cardinal
- January 23 - Gottfried Böhm, German architect
- January 30 - Delbert Mann, American television and film director

February-March


- February 7 - An Wang, Chinese-born computer pioneer (d. 1990)
- February 11 - Farouk I, King of Egypt (d. 1965)
- February 11 - Billy Halop, American actor (d. 1976)
- February 11 - Paul Peter Piech, American artist (d. 1996)
- February 12 - William Roscoe Estep, American Baptist historian (d. 2000)
- February 17 - Ivo Caprino, Norwegian film director (d. 2001)
- February 18 - Bill Cullen, American game show host (d. 1990)
- February 18 - Eddie Slovik, U.S. Army private (d. 1945)
- February 26 - Tony Randall, American actor (d. 2004)
- February 29 - Howard Nemerov, American poet (d. 1991)
- March 3 - James Doohan, Canadian-born actor (d. 2005)
- March 3 - Ronald Searle, British cartoonist
- March 10 - Boris Vian , French writer, poet, singer and musician
- March 11 - Nicolaas Bloembergen, Dutch physicist, Nobel Prize laureate
- March 14 - Hank Ketcham, American cartoonist (d. 2001)
- March 15 - Lawrence Sanders, American novelist (d. 1998)
- March 15 - E. Donnall Thomas, American physician, recipient of the Nobel Prize in Physiology or Medicine
- March 16 - Leo McKern, Australian actor (d. 2002)
- March 17 - Mujibur Rahman, Prime Minister of Bangladesh (d. 1975)
- March 19 - Kjell Aukrust, Norwegian poet and artist (d. 2002)
- March 20 - Pamela Harriman, English-born U.S. Ambassador to France (d. 1997)
- March 22 Werner Klemperer, German actor (d. 2000)
- March 25 - Patrick Troughton, British actor (d. 1987)
- March 25 - Arthur Wint, Jamaican runner (d. 1992)

April


- April 1 - Toshirô Mifune, Japanese actor (d. 1997)
- April 2 - Jack Webb, American actor, director, and producer (d. 1982)
- April 5 - Arthur Hailey, American writer
- April 6 - Edmond H. Fischer, Swiss-American biochemist, recipient of the Nobel Prize in Physiology or Medicine
- April 7 - Ravi Shankar, Indian sitar player
- April 11 - Peter O'Donnell, British cartoonist and writer
- April 15 - Thomas Stephen Szasz, Hungarian-born psychiatrist and writer
- April 13 - Liam Cosgrave, President of Ireland
- April 27 - Guido Cantelli, Italian conductor (d. 1956)
- April 29 - Harold Shapero, American composer

May


- May 2 - Jean-Marie Auberson, Swiss conductor (d. 2004)
- May 6 - Ratu Sir Kamisese Mara, first Prime Minister of Fiji and President of Fiji (d. 2004)
- May 9 - Richard Adams, English author
- May 18 - Pope John Paul II (d. 2005)
- May 18 - Lucia Mannucci, Italian singer (Quartetto Cetra)
- May 23 - Helen O'Connell, American singer (d. 1993)
- May 26 - Peggy Lee, American singer (d. 2002)
- May 28 - Gene Levitt, American television writer, producer, and director (d. 1999)
- May 29 - John Harsanyi, Hungarian-born economist, Nobel Prize laureate (d. 2000)
- May 30 - Franklin Schaffner, American film and television director (d. 1989)

June-July


- June 2 - Tex Schramm, American football team president and general manager (d. 2003)
- June 12 - Dave Berg, American cartoonist (d. 2002)
- June 12 - Jim Siedow, American actor (d. 2003)
- June 16 - José López Portillo, President of Mexico (d. 2004)
- June 17 - François Jacob, French biologist, recipient of the Nobel Prize in Physiology or Medicine
- June 25 - Ozan Marsh, American pianist
- July 10 - David Brinkley, American television reporter (d. 2003)
- July 10 - Owen Chamberlain, American physicist, Nobel Prize laureate
- July 17 - Juan Antonio Samaranch, Spanish International Olympic Committee president
- July 21 - Isaac Stern, Ukrainian-born violinist (d. 2001)
- July 24 - Bella Abzug, American politician (d. 1998)
- July 25 - Rosalind Franklin, British crystallographer (d.1958)

August-December


- August 8 - Leo Chiosso, Italian poet
- August 16 - Charles Bukowski, American writer (d. 1994)
- August 18 - Bob Kennedy, baseball player and manager (d. 2005)
- August 21 - Christopher Robin Milne, English author and bookseller (d. 1996)
- August 22 - Ray Bradbury, American writer
- August 29 - Charlie Parker, American jazz saxophonist and composer (d. 1955)
- September 10 - Fabio Taglioni, Italian motorcycle engineer (d. 2001)
- September 14 - Mario Benedetti, Uruguayan writer
- September 14 - Lawrence Klein, American economist, Nobel Prize laureate
- September 22 - William H. Riker, American political scientist (d. 1993)
- September 29 - Peter D. Mitchell, English chemist, Nobel Prize laureate
- October 1 - Charles Daudelin, Canadian sculptor (d. 2001)
- October 1 - Walter Matthau, American actor (d. 2000)
- October 6 - Pietro Consagra, Italian sculptor (d. 2005)
- October 8 - Frank Herbert, American author (d. 1986)
- October 9 - Jens Bjørneboe, Norwegian author (d. 1976)
- October 15 - Mario Puzo, American author (d. 1999)
- October 29 - Baruj Benacerraf, Venezuelan-born immunologist, recipient of the Nobel Prize in Physiology or Medicine
- October 31 - Fritz Walter, German football player (d. 2002)
- November 5 - Douglass North, American economist, Nobel Prize laureate
-