|
Multiprocessing
Multiprocessing 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.). According to some on-line dictionaries, 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 noting 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 somet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetric Multiprocessing
Symmetric multiprocessing or shared-memory multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all input and output devices, and are controlled by a single operating system instance that treats all processors equally, reserving none for special purposes. Most multiprocessor systems today use an SMP architecture. In the case of multi-core processors, the SMP architecture applies to the cores, treating them as separate processors. Professor John D. Kubiatowicz considers traditionally SMP systems to contain processors without caches. Culler and Pal-Singh in their 1998 book "Parallel Computer Architecture: A Hardware/Software Approach" mention: "The term SMP is widely used but causes a bit of confusion. ..The more precise description of what is intended by SMP is a shared memory multiprocessor where the cost of accessing a memory locatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymmetric Multiprocessing
An asymmetric multiprocessing (AMP or ASMP) system is a multiprocessor computer system where not all of the multiple interconnected central processing units (CPUs) are treated equally. For example, a system might allow (either at the hardware or operating system level) only one CPU to execute operating system code or might allow only one CPU to perform I/O operations. Other AMP systems might allow any CPU to execute operating system code and perform I/O operations, so that they were symmetric with regard to processor roles, but attached some or all peripherals to particular CPUs, so that they were asymmetric with respect to the peripheral attachment. Asymmetric multiprocessing was the only method for handling multiple CPUs before symmetric multiprocessing (SMP) was available. It has also been used to provide less expensive options on systems where SMP was available. Background and history For the room-size computers of the 1960s and 1970s, a cost-effective way to increase compute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer System
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs enable computers to perform a wide range of tasks. A computer system is a nominally complete computer that includes the hardware, operating system (main software), and peripheral equipment needed and used for full operation. This term may also refer to a group of computers that are linked and function together, such as a computer network or computer cluster. A broad range of industrial and consumer products use computers as control systems. Simple special-purpose devices like microwave ovens and remote controls are included, as are factory devices like industrial robots and computer-aided design, as well as general-purpose devices like personal computers and mobile devices like smartphones. Computers power the Internet, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola 68000
The Motorola 68000 (sometimes shortened to Motorola 68k or m68k and usually pronounced "sixty-eight-thousand") is a 16/32-bit complex instruction set computer (CISC) microprocessor, introduced in 1979 by Motorola Semiconductor Products Sector. The design implements a 32-bit instruction set, with 32-bit registers and a 16-bit internal data bus. The address bus is 24 bits and does not use memory segmentation, which made it easier to program for. Internally, it uses a 16-bit data arithmetic logic unit (ALU) and two more 16-bit ALUs used mostly for addresses, and has a 16-bit external data bus. For this reason, Motorola termed it a 16/32-bit processor. As one of the first widely available processors with a 32-bit instruction set, and running at relatively high speeds for the era, the 68k was a popular design through the 1980s. It was widely used in a new generation of personal computers with graphical user interfaces, including the Macintosh 128K, Amiga, Atari ST, and X6800 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Process (computing)
In computing, a process is the instance of a computer program that is being executed by one or many threads. There are many different process models, some of which are light weight, but almost all processes (even entire virtual machines) are rooted in an operating system (OS) process which comprises the program code, assigned system resources, physical and logical access permissions, and data structures to initiate, control and coordinate execution activity. Depending on the OS, a process may be made up of multiple threads of execution that execute instructions concurrently. While a computer program is a passive collection of instructions typically stored in a file on disk, a process is the execution of those instructions after being loaded from the disk into memory. Several processes may be associated with the same program; for example, opening up several instances of the same program often results in more than one process being executed. Multitasking is a method to allow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Babbage
Charles Babbage (; 26 December 1791 – 18 October 1871) was an English polymath. A mathematician, philosopher, inventor and mechanical engineer, Babbage originated the concept of a digital programmable computer. Babbage is considered by some to be " father of the computer". Babbage is credited with inventing the first mechanical computer, the Difference Engine, that eventually led to more complex electronic designs, though all the essential ideas of modern computers are to be found in Babbage's Analytical Engine, programmed using a principle openly borrowed from the Jacquard loom. Babbage had a broad range of interests in addition to his work on computers covered in his book ''Economy of Manufactures and Machinery''. His varied work in other fields has led him to be described as "pre-eminent" among the many polymaths of his century. Babbage, who died before the complete successful engineering of many of his designs, including his Difference Engine and Analytical En ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single Instruction, Multiple Data
Single instruction, multiple data (SIMD) is a type of parallel processing in Flynn's taxonomy. SIMD can be internal (part of the hardware design) and it can be directly accessible through an instruction set architecture (ISA), but it should not be confused with an ISA. SIMD describes computers with multiple processing elements that perform the same operation on multiple data points simultaneously. Such machines exploit data level parallelism, but not concurrency: there are simultaneous (parallel) computations, but each unit performs the exact same instruction at any given moment (just with different data). SIMD is particularly applicable to common tasks such as adjusting the contrast in a digital image or adjusting the volume of digital audio. Most modern CPU designs include SIMD instructions to improve the performance of multimedia use. SIMD has three different subcategories in Flynn's 1972 Taxonomy, one of which is SIMT. SIMT should not be confused with software t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRS-80 Model II
The TRS-80 Model II is a computer system launched by Tandy in October 1979, and targeted at the small-business market. It is not an upgrade of the original TRS-80 Model I, but a new system. The Model II was succeeded by the compatible TRS-80 Model 12, Model 16, Model 16B, and the Tandy 6000. Model II Background Tandy was surprised at the strong demand for the TRS-80 Model I from business purchasers. The computer was too limited for such use, so the company began development on the Model II in late 1978. It was announced in May 1979, deliveries began in October, and only Tandy-owned Radio Shack stores sold the computer. Tandy advertised the Model II as "a business computer — not a hobby, 'home' or personal computer". It claimed that the computer was "ideal for a small business, and also 'just right' for many time-consuming jobs within larger businesses", including those with mainframes or minicomputers. The base single disk version was , and a four disk version was . Hardware ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel 8021
The MCS-48 microcontroller series, Intel's first microcontroller, was originally released in 1976. Its first members were 8048, 8035 and 8748. The 8048 is probably the most prominent member of the family. Initially, this family was produced using NMOS (n-type metal–oxide–semiconductor) technology. In the early 1980s, it became available in CMOS technology. It was manufactured into the 1990s to support older designs that still used it. The MCS-48 series has a modified Harvard architecture, with internal or external program ROM and 64–256 bytes of internal (on-chip) RAM. The I/O is mapped into its own address space, separate from programs and data. Though the MCS-48 series was eventually replaced by the very successful MCS-51 series, it remained quite popular even by the year 2000 due to its low cost, wide availability, memory-efficient one-byte instruction set, and mature development tools. Because of this, it is used in high-volume, cost-sensitive consumer electr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zilog Z80
The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were delivered in March 1976, and it was officially introduced on the market in July 1976. With the revenue from the Z80, the company built its own chip factories and grew to over a thousand employees over the following two years. The Zilog Z80 is a software-compatible extension and enhancement of the Intel 8080 and, like it, was mainly aimed at embedded systems. Although used in that role, the Z80 also became one of the most widely used CPUs in desktop computers and home computers from the 1970s to the mid-1980s. It was also common in military applications, musical equipment such as synthesizers (like the Roland Jupiter-8), and coin-operated arcade games of the late 1970s and early 1980s, including ''Pac-Man''. Zilog licensed th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenix
Xenix is a discontinued version of the Unix operating system for various microcomputer platforms, licensed by Microsoft from AT&T Corporation in the late 1970s. The Santa Cruz Operation (SCO) later acquired exclusive rights to the software, and eventually replaced it with SCO UNIX (now known as SCO OpenServer). In the mid-to-late 1980s, Xenix was the most common Unix variant, measured according to the number of machines on which it was installed. Microsoft chairman Bill Gates said at Unix Expo in 1996 that, for a long time, Microsoft had the highest-volume AT&T Unix license. History Bell Labs, the developer of Unix, was part of the regulated Bell System and could not sell Unix directly to most end users (academic and research institutions excepted); it could, however, license it to software vendors who would then resell it to end users (or their own resellers), combined with their own added features. Microsoft, which expected that Unix would be its operating system of the futu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRS-80 Model 16
The TRS-80 Model II is a computer system launched by Tandy in October 1979, and targeted at the small-business market. It is not an upgrade of the original TRS-80 Model I, but a new system. The Model II was succeeded by the compatible TRS-80 Model 12, Model 16, Model 16B, and the Tandy 6000. Model II Background Tandy was surprised at the strong demand for the TRS-80 Model I from business purchasers. The computer was too limited for such use, so the company began development on the Model II in late 1978. It was announced in May 1979, deliveries began in October, and only Tandy-owned Radio Shack stores sold the computer. Tandy advertised the Model II as "a business computer — not a hobby, 'home' or personal computer". It claimed that the computer was "ideal for a small business, and also 'just right' for many time-consuming jobs within larger businesses", including those with mainframes or minicomputers. The base single disk version was , and a four disk version was . Hardware ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_School_-_Charles_Babbage_(1792–1871)_-_814168_-_National_Trust.jpg "Click for more on -> Charles Babbage")
