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 IBM System/360 Model 85. View of system console. The left side has a Microfiche Document Viewer | |
| Manufacturer | International Business Machines Corporation (IBM) |
|---|---|
| Product family | System/360 |
| Memory | 512 K - 4 M Core |
The IBM System/360 Model 85 is a high-end member of the System/360 family of computers, with many advanced features, and was announced in January 1968 and first shipped in December 1969. [1] IBM built only about 30 360/85 systems [1] [2] because of "a recession in progress". [3]
The four models of the 360/85 [4] are: I85 (512K), J85 (1M), K85 (2M) and L85 (4M), configured with two IBM 2365 Processor Storage units, four 2365 units, an IBM 2385 Processor Storage unit Model 1 (=2M), or an IBM 2385 Processor Storage unit Model 2 (=4M) respectively. The I85 includes two-way interleaved memory while the others provide four-way interleaving of memory access.
The 360/85, when equipped with the 709/7090/7094 Compatibility Feature, [6] with the use of an emulator program permits running 709, 7040, 7044, 7094 and 7094 II programs. [4] : p.9 [7]
In some respects, the System/360 Model 85 provided a glimpse into the future System/370 product line [8] (particularly the 370 Model 165) - which IBM announced two years later (1970). It used the MST circuitry that was later used in the initial System/370 models, and introduced features such as 128-bit floating point arithmetic and block multiplexor channels that are also part of the System/370 architecture.
The 360/85 uses microcode to control instruction execution, [9] unlike the completely-hardwired 360/75 and 360/91; the high-end models of System/370 also use horizontal microcode, except the IBM System/370 model 195. [10]
A control store is the part of a CPU's control unit that stores the CPU's microprogram. It is usually accessed by a microsequencer. A control store implementation whose contents are unalterable is known as a Read Only Memory (ROM) or Read Only Storage (ROS); one whose contents are alterable is known as a Writable Control Store (WCS).
IBM mainframes are large computer systems produced by IBM since 1952. During the 1960s and 1970s, IBM dominated the computer market with the 7000 series and the later System/360, followed by the System/370. Current mainframe computers in IBM's line of business computers are developments of the basic design of the System/360.
In processor design, microcode serves as an intermediary layer situated between the central processing unit (CPU) hardware and the programmer-visible instruction set architecture of a computer. It consists of a set of hardware-level instructions that implement higher-level machine code instructions or control internal finite-state machine sequencing in many digital processing components. While microcode is utilized in general-purpose CPUs in contemporary desktops, it also functions as a fallback path for scenarios that the faster hardwired control unit is unable to manage.
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 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, featuring 8-bit byte addressing and binary, decimal and hexadecimal floating-point calculations.
The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the product announcement. In September 1990, the System/370 line was replaced with the System/390.
The IBM 7090 is a second-generation transistorized version of the earlier IBM 709 vacuum tube mainframe computer that was designed for "large-scale scientific and technological applications". The 7090 is the fourth member of the IBM 700/7000 series scientific computers. The first 7090 installation was in December 1959. In 1960, a typical system sold for $2.9 million or could be rented for $63,500 a month.
The IBM 700/7000 series is a series of large-scale (mainframe) computer systems that were made by IBM through the 1950s and early 1960s. The series includes several different, incompatible processor architectures. The 700s use vacuum-tube logic and were made obsolete by the introduction of the transistorized 7000s. The 7000s, in turn, were eventually replaced with System/360, which was announced in 1964. However the 360/65, the first 360 powerful enough to replace 7000s, did not become available until November 1965. Early problems with OS/360 and the high cost of converting software kept many 7000s in service for years afterward.
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.
The IBM System/360 Model 67 (S/360-67) was an important IBM mainframe model in the late 1960s. Unlike the rest of the S/360 series, it included features to facilitate time-sharing applications, notably a Dynamic Address Translation unit, the "DAT box", to support virtual memory, 32-bit addressing and the 2846 Channel Controller to allow sharing channels between processors. The S/360-67 was otherwise compatible with the rest of the S/360 series.
The IBM 8000 series was a proposed transistor-based successor to the IBM 7000 series. Important engineers on the project included Fred Brooks and Gerry Blaauw. The project plan for the 8000 series was presented by Fred Brooks in January 1961. Despite some technical successes, the project became a political football, amid IBM's search for a unified product line. The project was canceled in 1961 by Bob Evans, supplanted by the successful System/360 series.
The history of IBM mainframe operating systems is significant within the history of mainframe operating systems, because of IBM's long-standing position as the world's largest hardware supplier of mainframe computers. IBM mainframes run operating systems supplied by IBM and by third parties.
The IBM 2365 Processor Storage is a magnetic-core memory storage unit that is a component of the IBM System/360 models 65, 67, 75 and 85 computers, which were released between 1965 and 1968.
The IBM 2361 Large Capacity Storage (LCS) is an optional component of the IBM System/360 models 50, 65 (when not being used as a multiprocessor), and 75 computers. Storage is implemented using magnetic cores; the cycle time is 8 microseconds and the access time is 3.6 microseconds. This component is also called IBM 2361 Core Storage or IBM 2361 Large Core Storage. It provides additional main storage with a slower access time than the standard storage of the machine—for example its 8μsec compares to 750nsec for main storage on the Model 65.
The IBM System/360 Model 50 is a member of the IBM System/360 family of computers. The Model 50 was announced in April 1964 with the other initial models of the family, and first shipped in August 1965 to the Bank of America.
The IBM System/360 Model 65 is a member of the IBM System/360 family of computers. It was announced April 1965, and replaced two models, the Model 60 and Model 62, announced one year prior but never shipped. It was discontinued in March 1974.
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".
The IBM System/370 Model 165 were jointly announced June 30, 1970 as "designed for ... the Seventies." That same day IBM announced the 370/195. They were the first three models of the IBM System/370 line of computers.
The IBM System/370 Model 168 and Model 158 were both announced on August 2, 1972. Prior 370 systems had not "offered virtual storage capability, which was to be a hallmark of the 370 line," and some said that the 168 and 158 were the first "real 370" products. By contrast, "in 1972, the System/370 Advanced Function was released and had new Address Relocation Hardware and now supported four new operating systems ."
In addition to the drums used as main memory by IBM, e.g., IBM 305, IBM 650, IBM offered drum devices as secondary storage for the 700/7000 series and System/360 series of computers.
Its basic design includes monolithic circuits, very wide data paths, an 80-nanosecond internal buffer of at least 16K bytes, and a high-speed multiply feature.
In May 1968, during the course of contention over Model 85 architecture, which was intended to represent a first step toward NS architecture...
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