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Alliant Computer Systems
Alliant Computer Systems Corporation was a computer company that designed and manufactured parallel computing systems. Together with Pyramid Technology and Sequent Computer Systems, Alliant's machines pioneered the symmetric multiprocessing market. One of the more successful companies in the group, over 650 Alliant systems were produced over their lifetime. The company was hit by a series of financial problems and went bankrupt in 1992. History 1980s Alliant was founded, as Dataflow Systems, in May 1982 by Ron Gruner, Craig Mundie and Rich McAndrew to produce machines for scientific and engineering users who needed smaller, less costly machines than offerings from Cray Computer and similar high-end vendors. Machines that addressed this market segment later became known as minisupercomputers. At the time there was a huge gap on the price/performance curve as a highly configured VAX 11/780 had a performance of about a MIP and MegaFLOP for around $1M USD and a Cray-1S or Cray 1M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Private Company
A privately held company (or simply a private company) is a company whose Stock, shares and related rights or obligations are not offered for public subscription or publicly negotiated in their respective listed markets. Instead, the Private equity, company's stock is offered, owned, traded or exchanged privately, also known as "over-the-counter (finance), over-the-counter". Related terms are unlisted organisation, unquoted company and private equity. Private companies are often less well-known than their public company, publicly traded counterparts but still have major importance in the world's economy. For example, in 2008, the 441 list of largest private non-governmental companies by revenue, largest private companies in the United States accounted for $1.8 trillion in revenues and employed 6.2 million people, according to ''Forbes''. In general, all companies that are not owned by the government are classified as private enterprises. This definition encompasses both publ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scalar Processor
Scalar processors are a class of computer processors that process only one data item at a time. Typical data items include integers and floating point numbers. Classification A scalar processor is classified as a single instruction, single data (SISD) processor in Flynn's taxonomy. The Intel 486 is an example of a scalar processor. It is to be contrasted with a vector processor where a single instruction operates simultaneously on multiple data items (and thus is referred to as a single instruction, multiple data (SIMD) processor). The difference is analogous to the difference between scalar and vector arithmetic. The term ''scalar'' in computing dates to the 1970 and 1980s when vector processors were first introduced. It was originally used to distinguish the older designs from the new vector processors. Superscalar processor A superscalar processor (such as the Intel P5) may execute more than one instruction during a clock cycle by simultaneously dispatching multiple in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiprocessing
Multiprocessing (MP) is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. There are many variations on this basic theme, and the definition of multiprocessing can vary with context, mostly as a function of how CPUs are defined ( multiple cores on one die, multiple dies in one package, multiple packages in one system unit, etc.). A multiprocessor is a computer system having two or more processing units (multiple processors) each sharing main memory and peripherals, in order to simultaneously process programs. A 2009 textbook defined multiprocessor system similarly, but noted that the processors may share "some or all of the system’s memory and I/O facilities"; it also gave tightly coupled system as a synonymous term. At the operating system level, ''multiprocessing'' is sometimes used to refer to the executi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola 68030
The Motorola 68030 ("''sixty-eight-oh-thirty''") is a 32-bit microprocessor in the Motorola 68000 family. It was released in 1987. The 68030 was the successor to the Motorola 68020, and was followed by the Motorola 68040. In keeping with general Motorola naming, this CPU is often referred to as the 030 (pronounced ''oh-three-oh'' or ''oh-thirty''). The 68030 is essentially a 68020 with a memory management unit (MMU) and instruction and data caches of 256 bytes each. It added a burst mode for the caches, where four longwords can be loaded into the cache in a single operation. The MMU was mostly compatible with the external 68851 that would be used with the 68020, but being internal allowed it to access memory one cycle faster than a 68020/68851 combo. The 68030 did not include a built-in floating-point unit (FPU), and was generally used with the 68881 and the faster 68882. The addition of the FPU was a major design note of the subsequent 68040. The 68030 typically increases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola 68020
The Motorola 68020 is a 32-bit microprocessor from Motorola, released in 1984. A lower-cost version was also made available, known as the 68EC020. In keeping with naming practices common to Motorola designs, the 68020 is usually referred to as the "020", pronounced "oh-two-oh" or "oh-twenty". The 020 was in the market for a relatively short time. The Motorola 68030 was announced in September 1986 and began deliveries in the summer of 1987. Priced about the same as the 020 of the time, the 030 was significantly faster and quickly replaced in 020 in almost every use. History 68000 and 68010 At the time the Motorola 68000 was designed, Motorola's design and fabrication services were outdated. Although even small companies like MOS Technology and Zilog had moved on to silicon gate depletion mode NMOS logic on ever-larger semiconductor wafer, wafers, Motorola was still using metal gates and enhancement mode and their largest fab worked on 4-inch wafers long after most lines had moved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola 68012
The Motorola MC68010 and Motorola MC68012 are 16/32-bit microprocessors from Motorola, released in 1982 as successors to the Motorola 68000. The 68010 and 68012 added virtualization features, optimized loops and fixed several small flaws to the 68000. The MC68010 variants were pin compatible with its predecessor while the MC68012 is an 84-pin PGA version with its directly accessible memory space extended to 2 GiB. Differences between 68010/68012 and 68000 The 68010 and 68012 are completely user-mode compatible with the 68000, except that the MOVE from SR instruction traps in user mode, so that, to support user-mode code using that instruction, a supervisor-mode trap handler must simulate the instruction and continue the user-mode code after that instruction. This was done so that the 68010 and 68012 would meet the Popek and Goldberg virtualization requirements, specifically that a new OS could run as guest and not be aware. A new unprivileged MOVE from CCR instruction w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interactive Processing
Across the many fields concerned with interactivity, including information science, computer science, human-computer interaction, communication, and industrial design, there is little agreement over the meaning of the term "interactivity", but most definitions are related to interaction between users and computers and other machines through a user interface. Interactivity can however also refer to interaction between people. It nevertheless usually refers to interaction between people and computers – and sometimes to interaction between computers – through software, hardware, and networks. Multiple views on interactivity exist. In the "contingency view" of interactivity, there are three levels: #Not interactive, when a message is not related to previous messages. #Reactive, when a message is related only to one immediately previous message. #Interactive, when a message is related to a number of previous messages and to the relationship between them. One body of research h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribbon Cable
A ribbon cable is a cable with many conducting wires running parallel to each other on the same flat plane. As a result, the cable is wide and flat. Its name comes from its resemblance to a piece of ribbon. Ribbon cables are usually seen for internal peripherals in computers, such as hard drives, CD drives and floppy drives. On some older computer systems (such as the BBC Micro and Apple II) they were used for external connections as well. The ribbon-like shape interferes with computer cooling#Use of rounded cables, computer cooling by disrupting airflow within the case and also makes the cables awkward to handle, especially when there are a lot of them; as a result, round cables have almost entirely replaced ribbon cables for external connections and are increasingly being used internally as well. History The original form of ribbon cable was two-conductor 300 ohm ''twin lead'' cable used for radio and television, which is also called "ribbon cable". However the more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Parallelism
Data parallelism is parallelization across multiple processors in parallel computing environments. It focuses on distributing the data across different nodes, which operate on the data in parallel. It can be applied on regular data structures like arrays and matrices by working on each element in parallel. It contrasts to task parallelism as another form of parallelism. A data parallel job on an array of ''n'' elements can be divided equally among all the processors. Let us assume we want to sum all the elements of the given array and the time for a single addition operation is Ta time units. In the case of sequential execution, the time taken by the process will be ''n''×Ta time units as it sums up all the elements of an array. On the other hand, if we execute this job as a data parallel job on 4 processors the time taken would reduce to (''n''/4)×Ta + merging overhead time units. Parallel execution results in a speedup of 4 over sequential execution. The Locality of reference, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compiler
In computing, a compiler is a computer program that Translator (computing), translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a lower level language, low-level programming language (e.g. assembly language, object code, or machine code) to create an executable program.Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman - Second Edition, 2007 There are many different types of compilers which produce output in different useful forms. A ''cross-compiler'' produces code for a different Central processing unit, CPU or operating system than the one on which the cross-compiler itself runs. A ''bootstrap compiler'' is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language. Related software ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-level Language
A high-level programming language is a programming language with strong abstraction from the details of the computer. In contrast to low-level programming languages, it may use natural language ''elements'', be easier to use, or may automate (or even hide entirely) significant areas of computing systems (e.g. memory management), making the process of developing a program simpler and more understandable than when using a lower-level language. The amount of abstraction provided defines how "high-level" a programming language is. In the 1960s, a high-level programming language using a compiler was commonly called an '' autocode''. Examples of autocodes are COBOL and Fortran. The first high-level programming language designed for computers was Plankalkül, created by Konrad Zuse. However, it was not implemented in his time, and his original contributions were largely isolated from other developments due to World War II, aside from the language's influence on the "Superplan" langua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latency (engineering)
Latency, from a general point of view, is a time delay between the Causality, cause and the effect of some physical change in the system being observed. Lag (video games), Lag, as it is known in Gaming culture, gaming circles, refers to the latency between the input to a simulation and the visual or auditory response, often occurring because of network delay in online games. The original meaning of “latency”, as used widely in psychology, medicine and most other disciplines, derives from “latent”, a word of Latin origin meaning “hidden”. Its different and relatively recent meaning (this topic) of “lateness” or “delay” appears to derive from its superficial similarity to the word “late”, from the old English “laet”. Latency is physically a consequence of the limited velocity at which any Event (relativity), physical interaction can propagate. The magnitude of this velocity is always less than or equal to the speed of light. Therefore, every physical s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
