360 Model 25
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360 Model 25
The IBM System/360 Model 25 is a low-end member of the IBM System/360 family. It was announced on January 3, 1968, 3 years before the IBM System/360 Model 22, as a "bridge between its old and new computing systems". History At a time when lower priced alternatives, such as service bureaus - by 1968, there were 32 such service bureaus serving the US National Institutes of Health (NIH) alone - and prior generation systems, such as the Honeywell 200, a competitor to IBM's own IBM 1401, were available, this model provided a stop-gap measure. Both the Model 25 and the Model 22, which had been marketed as entry level systems, were withdrawn on the same day, October 7, 1977. Models The Model 25 can be configured with 16K, 24K, 32K, or 48K of core memory. Characteristics The base Model 25 implements the System/360 standard and commercial instruction sets. The scientific or universal instruction sets are optional features. The Model 25 logic is built on IBM SLT modules mounted on plug ...
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System/360
The IBM System/360 (S/360) is a family of mainframe computer systems that was announced by IBM on April 7, 1964, and delivered between 1965 and 1978. It was the first family of computers designed to cover both commercial and scientific applications and to cover a complete range of applications from small to large. The design distinguished between architecture and implementation, allowing IBM to release a suite of compatible designs at different prices. All but the only partially compatible Model 44 and the most expensive systems use microcode to implement the instruction set, which features 8-bit byte addressing and binary, decimal, and hexadecimal floating-point calculations. The System/360 family introduced IBM's Solid Logic Technology (SLT), which packed more transistors onto a circuit card, allowing more powerful but smaller computers to be built. The slowest System/360 model announced in 1964, the IBM System/360 Model 30, Model 30, could perform up to 34,500 instructions ...
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IBM 1403
The IBM 1403 line printer was introduced as part of the IBM 1401 computer in 1959 and had an especially long life in the IBM product line. Description The original model can print 600 lines of text per minute and can skip blank lines at up to 75 inches per second (190 cm/s), while the model 3 can print at up to 1400 lines per minute. The standard model has 120 print positions. An additional 12 positions are available as an option. A print chain with up to 15 copies of the character set spins horizontally in front of the ribbon and paper. Hammers strike the paper from behind at exactly the right moment to print a character as it goes by. In later models, the print chain is replaced by a print train; print slugs instead of being mounted on a chain are placed in a track. The 1403 chain or train contains 240 characters, however numerous duplications allow a line to be printed in less than the 0.4 s required for one full rotation. The original standard "A" chain co ...
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COBOL
COBOL (; an acronym for "common business-oriented language") is a compiled English-like computer programming language designed for business use. It is an imperative, procedural and, since 2002, object-oriented language. COBOL is primarily used in business, finance, and administrative systems for companies and governments. COBOL is still widely used in applications deployed on mainframe computers, such as large-scale batch and transaction processing jobs. However, due to its declining popularity and the retirement of experienced COBOL programmers, programs are being migrated to new platforms, rewritten in modern languages or replaced with software packages. Most programming in COBOL is now purely to maintain existing applications; however, many large financial institutions were still developing new systems in COBOL as late as 2006. COBOL was designed in 1959 by CODASYL and was partly based on the programming language FLOW-MATIC designed by Grace Hopper. It was created as part ...
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BOS/360
Basic Operating System/360 (BOS/360) was an early IBM System/360 operating system. Origin BOS was one of four System/360 Operating System versions developed by the IBM General Products Division (GPD) in Endicott, New York to fill a gap at the low end of the System/360 line when it became apparent that OS/360 was not able to run on the smallest systems. BPS (Basic Programming support) was designed to run on systems with a minimum of 8 KB of main storage and no disk. BOS was intended for disk systems with at least 8 KB and one 2311 disk drive. DOS and TOS were developed from BOS for systems with at least 16 KB and either disks (DOS) or tape drives only (TOS). BOS was released in October 1965, nearly two years before OS/360, thus BOS was the only disk based operating system available at launch for a machine that was marketed as disk based. Components BOS consisted of the following components: * Control programs: ** The supervisor. ** Job control capable o ...
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DOS/360 And Successors
Disk Operating System/360, also DOS/360, or simply DOS, is the discontinued first member of a sequence of operating systems for IBM System/360, System/370 and later mainframes. It was announced by IBM on the last day of 1964, and it was first delivered in June 1966. In its time, DOS/360 was the most widely used operating system in the world. DOS versions BOS/360 The Basic Operating System(BOS) was an early version of DOS and TOS which could provide usable functionality on a system with as little as 8 KB of main storage and one 2311 disk drive. TOS/360 TOS/360 (Tape Operating System/360, not a DOS as such and not so called) was an IBM operating system for the System/360, used in the early days around 1965 to support the System/360 Model 30 and similar platforms. TOS, as per the "Tape" in the name, required a tape drive. It shared most of the code base and some manuals with IBM's DOS/360. TOS went through 14 releases, and was discontinued when disks such as the IBM 2 ...
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Plug Compatible
Plug compatible refers to " hardware that is designed to perform exactly like another vendor's product." The term PCM was originally applied to manufacturers who made replacements for IBM peripherals. Later this term was used to refer to IBM-compatible computers. PCM and peripherals Before the rise of the PCM peripheral industry, computing systems were either configured with peripherals designed and built by the CPU vendor, or designed to use vendor-selected rebadged devices. The first example of plug compatible IBM subsystems were tape drives and controls offered by Telex beginning 1965. Memorex in 1968 was first to enter the IBM plug-compatible disk followed shortly thereafter by a number of suppliers such as CDC, Itel, and Storage Technology Corporation. This was boosted by the world's largest user of computing equipment in both directions. Ultimately plug-compatible products were offered for most peripherals and system main memory. PCM and computer systems A plug-compatib ...
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IBM 1400 Series
The IBM 1400 series were second-generation (transistor) mid-range business decimal computers that IBM marketed in the early 1960s. The computers were offered to replace tabulating machines like the IBM 407. The 1400-series machines stored information in magnetic cores as variable-length character strings separated on the left by a special bit, called a "wordmark," and on the right by a "record mark." Arithmetic was performed digit-by-digit. Input and output support included punched card, magnetic tape, and high-speed line printers. Disk storage was also available. Many members of the series could be used as independent systems, as extensions to IBM punched-card equipment, or as auxiliary equipment to other computer systems. Some, however, were intended for specific applications or were economical only as independent systems. History The 1401, announced on October 5, 1959, was the first member of the IBM 1400 series. It was the first computer to deploy over 10,000 units. Th ...
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History Of IBM CKD Controllers
Beginning with its 1964 System/360 announcement, IBM's mainframes initially accessed CKD (Count key data) subsystems via a channel connected to separate Storage Control Units (SCUs) with attached Direct Access Storage Devices (DASD), typically a hard disk drive. This practice continued in IBM's larger mainframes thru System/370; however low end systems generally used lower cost integrated attachments where the function of the SCU was combined with that of the channel, typically called an Integrated File Adapter. The System/360 selector channel was followed by the System/370 block multiplexor channel which could operate as a selector channel to allow attachment of legacy subsystems. The SCU evolved into a Director and Controller, the latter typically labelled an "A-unit" (or A-Box") with the controller and at least one DASD physically in an A-unit. An Integrated Storage Control (ISC) is a Director within the cabinet of an IBM System. A Director could attach from one to four A ...
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IBM System/360 Model 44
The IBM System/360 Model 44 is a specialized member of the IBM System/360 family, with a variant of the System/360 computer architecture, designed for scientific computing, real-time computing, process control and numerical control (NC). The Model 44 was announced August 16, 1965 and withdrawn September 24, 1973. Architecture The base Model 44 lacks the storage-to-storage character and decimal instruction sets of a standard System/360, however an "extended instruction set" feature was available to provide the missing instructions. The machine features four unique instructions: ''Change Priority Mask'' (CHPM), ''Load PSW Special'' (LPSX), ''Read Direct Word'' (RDDW), and ''Write Direct Word'' (WRDW). The system comes with four memory sizes: E (32 KiB), F (64 KiB), G (128 KiB), and H (256 KiB), with an access time of 1 μs, which puts it closer to the Model 65 (.75 μs) than the Model 50 (2.0 μs). Storage protection is an optional feature. G ...
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I/O Channel
In computing, channel I/O is a high-performance input/output (I/O) architecture that is implemented in various forms on a number of computer architectures, especially on mainframe computers. In the past, channels were generally implemented with custom devices, variously named channel, I/O processor, I/O controller, I/O synchronizer, or ''DMA controller''. Overview Many I/O tasks can be complex and require logic to be applied to the data to convert formats and other similar duties. In these situations, the simplest solution is to ask the CPU to handle the logic, but because I/O devices are relatively slow, a CPU could waste time (in computer perspective) waiting for the data from the device. This situation is called 'I/O bound'. Channel architecture avoids this problem by processing some or all of the I/O task without the aid of the CPU by offloading the work to dedicated logic. Channels are logically self-contained, with sufficient logic and working storage to handle I/O tasks. ...
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Request Price Quotation
Request price quotation or RPQ is a long-standing IBM designation for a product or component that is potentially available, but that is not on the "standard" price list. Typical RPQ offerings are custom interfaces, hardware modifications, research or experimental systems, or variable-cost items. In the days of IBM's large mainframes, e.g. the System/360 and System/370 series, many unusual features were flagged as "RPQ". A special-order software item is known as a Programming Request Price Quotation or PRPQ. Examples The standard punched card code for the groupmark character on the IBM 1401 computer system used punches in rows 12, 7, and 8 of a card column (written as 12-7-8). The older IBM 705 computer used 12-5-8 for this character. An RPQ was available for the 1401 for compatibility that allowed the system to read or punch the 705 code rather than the standard code. Since not all 1401 users would need this feature it was marketed as an RPQ. The features used by the Compati ...
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IBM 2314
IBM manufactured magnetic disk storage devices from 1956 to 2003, when it sold its hard disk drive business to Hitachi. Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible for many of the innovations in these products and their technologies. The basic mechanical arrangement of hard disk drives has not changed since the IBM 1301. Disk drive performance and characteristics are measured by the same standards now as they were in the 1950s. Few products in history have enjoyed such spectacular declines in cost and physical size along with equally dramatic improvements in capacity and performance. IBM manufactured 8-inch floppy disk drives from 1969 until the mid-1980s, but did not become a significant manufacturer of smaller-sized, 5.25- or 3.5-inch floppy disk drives (the dimension refers to the diameter of the floppy disk, not the size of the drive). IBM always offered its magnetic disk drives for sale but did ...
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