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PC-based IBM-compatible Mainframes
Since the rise of the personal computer in the 1980s, IBM and other vendors have created PC-based IBM-compatible mainframes which are compatible with the larger IBM mainframe computers. For a period of time PC-based mainframe-compatible systems had a lower price and did not require as much electricity or floor space. However, they sacrificed performance and were not as dependable as mainframe-class hardware. These products have been popular with mainframe developers, in education and training settings, for very small companies with non-critical processing, and in certain disaster relief roles (such as field insurance adjustment systems for hurricane relief). Background Up until the mid-1990s, mainframes were very large machines that often occupied entire rooms. The rooms were often air conditioned and had special power arrangements to accommodate the three-phase electric power required by the machines. Modern mainframes are now physically comparatively small and require little o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or technician. Unlike large, costly minicomputers and mainframes, time-sharing by many people at the same time is not used with personal computers. Primarily in the late 1970s and 1980s, the term home computer was also used. Institutional or corporate computer owners in the 1960s had to write their own programs to do any useful work with the machines. While personal computer users may develop their own applications, usually these systems run commercial software, free-of-charge software (" freeware"), which is most often proprietary, or free and open-source software, which is provided in "ready-to-run", or binary, form. Software for personal computers is typically developed and distributed independently from the hardware or operating sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel 8088
The Intel 8088 ("''eighty-eighty-eight''", also called iAPX 88) microprocessor is a variant of the Intel 8086. Introduced on June 1, 1979, the 8088 has an eight-bit external data bus instead of the 16-bit bus of the 8086. The 16-bit registers and the one megabyte address range are unchanged, however. In fact, according to the Intel documentation, the 8086 and 8088 have the same execution unit (EU)—only the bus interface unit (BIU) is different. The original IBM PC is based on the 8088, as are its clones. History and description The 8088 was designed at Intel's laboratory in Haifa, Israel, as were a large number of Intel's processors. The 8088 was targeted at economical systems by allowing the use of an eight-bit data path and eight-bit support and peripheral chips; complex circuit boards were still fairly cumbersome and expensive when it was released. The prefetch queue of the 8088 was shortened to four bytes, from the 8086's six bytes, and the prefetch algorithm was sli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Personal System/2
The Personal System/2 or PS/2 is IBM's second generation of personal computers. Released in 1987, it officially replaced the IBM PC, XT, AT, and PC Convertible in IBM's lineup. Many of the PS/2's innovations, such as the 16550 UART (serial port), 1440 KB 3.5-inch floppy disk format, 72-pin SIMMs, the PS/2 port, and the VGA video standard, went on to become standards in the broader PC market. The PS/2 line was created by IBM partly in an attempt to recapture control of the PC market by introducing the advanced yet proprietary Micro Channel architecture (MCA) on higher-end models. These models were in the strange position of being incompatible with the IBM-compatible hardware standards previously established by IBM and adopted in the PC industry. However, IBM's initial PS/2 computers were popular with target market corporate buyers, and by September 1988 IBM reported that it had sold 3 million PS/2 machines. This was only 18 months after the new range had been introduced. M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micro Channel Architecture
Micro Channel architecture, or the Micro Channel bus, is a proprietary 16- or 32-bit parallel computer bus introduced by IBM in 1987 which was used on PS/2 and other computers until the mid-1990s. Its name is commonly abbreviated as "MCA", although not by IBM. In IBM products, it superseded the ISA bus and was itself subsequently superseded by the PCI bus architecture. Background The development of Micro Channel was driven by both technical and business pressures. Technology The IBM AT bus, which later became known as the Industry Standard Architecture (ISA) bus, had a number of technical design limitations, including: * A slow bus speed. * A limited number of interrupts, fixed in hardware. * A limited number of I/O device addresses, also fixed in hardware. * Hardwired and complex configuration with no conflict resolution. * Deep links to the architecture of the 80x86 chip familyUse of the ISA bus outside of machines employing the 80x86 CPU family was rare. Notable non- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Workstation
A workstation is a special computer designed for technical or scientific applications. Intended primarily to be used by a single user, they are commonly connected to a local area network and run multi-user operating systems. The term ''workstation'' has been used loosely to refer to everything from a mainframe computer terminal to a PC connected to a network, but the most common form refers to the class of hardware offered by several current and defunct companies such as Sun Microsystems, Silicon Graphics, Apollo Computer, DEC, HP, NeXT, and IBM which powered the 3D computer graphics revolution of the late 1990s. Workstations offer higher performance than mainstream personal computers, especially in CPU, graphics, memory, and multitasking. Workstations are optimized for the visualization and manipulation of different types of complex data such as 3D mechanical design, engineering simulations like computational fluid dynamics, animation, medical imaging, image rende ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computerworld
''Computerworld'' (abbreviated as CW) is an ongoing decades old professional publication which in 2014 "went digital." Its audience is information technology (IT) and business technology professionals, and is available via a publication website and as a digital magazine. As a printed weekly during the 1970s and into the 1980s, ''Computerworld'' was the leading trade publication in the data processing industry. Indeed, based on circulation and revenue it was one of the most successful trade publications in any industry. Later in the 1980s it began to lose its dominant position. It is published in many countries around the world under the same or similar names. Each country's version of ''Computerworld'' includes original content and is managed independently. The parent company of Computerworld US is IDG Communications. History The first issue was published in 1967. Going international The company IDG International Data Group (IDG, Inc.) is a market intelligence and demand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Page Cache
In computing, a page cache, sometimes also called disk cache, is a transparent cache for the pages originating from a secondary storage device such as a hard disk drive (HDD) or a solid-state drive (SSD). The operating system keeps a page cache in otherwise unused portions of the main memory (RAM), resulting in quicker access to the contents of cached pages and overall performance improvements. A page cache is implemented in kernels with the paging memory management, and is mostly transparent to applications. Usually, all physical memory not directly allocated to applications is used by the operating system for the page cache. Since the memory would otherwise be idle and is easily reclaimed when applications request it, there is generally no associated performance penalty and the operating system might even report such memory as "free" or "available". When compared to main memory, hard disk drive read/writes are slow and random accesses require expensive disk seeks; as a resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BYTE
The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit of memory in many computer architectures. To disambiguate arbitrarily sized bytes from the common 8-bit definition, network protocol documents such as The Internet Protocol () refer to an 8-bit byte as an octet. Those bits in an octet are usually counted with numbering from 0 to 7 or 7 to 0 depending on the bit endianness. The first bit is number 0, making the eighth bit number 7. The size of the byte has historically been hardware-dependent and no definitive standards existed that mandated the size. Sizes from 1 to 48 bits have been used. The six-bit character code was an often-used implementation in early encoding systems, and computers using six-bit and nine-bit bytes were common in the 1960s. These systems often had memory wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EBCDIC
Extended Binary Coded Decimal Interchange Code (EBCDIC; ) is an eight- bit character encoding used mainly on IBM mainframe and IBM midrange computer operating systems. It descended from the code used with punched cards and the corresponding six-bit binary-coded decimal code used with most of IBM's computer peripherals of the late 1950s and early 1960s. It is supported by various non-IBM platforms, such as Fujitsu-Siemens' BS2000/OSD, OS-IV, MSP, and MSP-EX, the SDS Sigma series, Unisys VS/9, Unisys MCP and ICL VME. History EBCDIC was devised in 1963 and 1964 by IBM and was announced with the release of the IBM System/360 line of mainframe computers. It is an eight-bit character encoding, developed separately from the seven-bit ASCII encoding scheme. It was created to extend the existing Binary-Coded Decimal (BCD) Interchange Code, or BCDIC, which itself was devised as an efficient means of encoding the two ''zone'' and ''number'' punches on punched cards into six ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASCII
ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of technical limitations of computer systems at the time it was invented, ASCII has just 128 code points, of which only 95 are , which severely limited its scope. All modern computer systems instead use Unicode, which has millions of code points, but the first 128 of these are the same as the ASCII set. The Internet Assigned Numbers Authority (IANA) prefers the name US-ASCII for this character encoding. ASCII is one of the IEEE milestones. Overview ASCII was developed from telegraph code. Its first commercial use was as a seven- bit teleprinter code promoted by Bell data services. Work on the ASCII standard began in May 1961, with the first meeting of the American Standards Association's (ASA) (now the American National Standards ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logical Disk
A logical disk, logical volume or virtual disk (VD or vdisk for short) is a virtual device that provides an area of usable storage capacity on one or more physical disk drive(s) in a computer system. The disk is described as ''logical'' or ''virtual'' because it does not actually exist as a single physical entity in its own right. The goal of the logical disk is to provide computer software with what seems a contiguous storage area, sparing them the burden of dealing with the intricacies of storing files on multiple physical units. Most modern operating systems provide some form of logical volume management. Levels Logical disks can be defined at various levels in the storage infrastructure. Operating system An operating system may define ''volumes'' or ''logical disks'' and assign each to one physical disk, more than one physical disk or part of the storage area of a physical disk. For example, Windows NT can create several partitions on a hard disk drive, each of which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VM/CMS
VM (often: VM/CMS) is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The following versions are known: ;Virtual Machine Facility/370 :VM/370, released in 1972, is a System/370 reimplementation of earlier CP/CMS operating system. ;VM/370 Basic System Extensions Program Product :VM/BSE (BSEPP) is an enhancement to VM/370 that adds support for more devices (such as 3370-type fixed-block-architecture DASD drives), improvements to the CMS environment (such as an improved editor), and some stability enhancements to CP. ;VM/370 System Extensions Program Product :VM/SE (SEPP) is an enhancement to VM/370 that includes the facilities of VM/BSE, as well as a few additional fixes and features. ;Virtual Machine/System Product :VM/SP, a milestone version, replaces VM/370, VM/BSE and VM/SE. Release 1 added EXEC2 and XEDIT System Produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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