IBM System/360 Model 44The 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 The Model 44 was announced August 16, 1965 and withdrawn September 24, 1973.
IBM System/360 Model 20The IBM System/360 Model 20 is the smallest member of the IBM System/360 family announced in November 1964. The Model 20 supports only a subset of the System/360 instruction set, with binary numbers limited to 16 bits and no floating point arithmetic.
IBM System/360 Model 67The 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.
Instruction set architectureAn instruction set architecture (ISA) is an abstract model that defines the programmable interface of the CPU of a computer, defining how software interacts with hardware. A device (i.e. CPU) that interprets instructions described by an ISA is an implementation of that ISA. Generally, the same ISA is used for a family of related CPU devices.
Program counterA program counter (PC) is a register that stores where a computer program is being executed by a processor. It is also commonly called the instruction pointer (IP) in Intelx86 and Itaniummicroprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer. Usually, a PC stores the memory address of an instruction.IBM hexadecimal floating-pointHexadecimal floating-point (HFP) is a format for encoding floating-point numbers first introduced on the IBMSystem/360 computers, and supported on subsequent machines based on that architecture, as well as machines which were intended to be application-compatible with System/360. In comparison to IEEE 754 floating point, the HFP format has a longer significand, and a shorter exponent. All HFP formats have 7 bits of exponent with a bias of 64.
Computer architectureIn computer science and computer engineering, a computer architecture is the conceptual design and operational structure of a computer system that define how component parts are organized and interact to execute programs efficiently. It is often a general description that ignores precise implementation details. It covers the instruction set architecture, CPU microarchitecture, memory, and input/output systems.
IBM System/360The IBM System/360 (S/360) is a family of computer systems announced by IBM on April 7, 1964, and delivered between 1965 and 1978. System/360 was the first family of computers designed to cover both commercial and scientific applications and a complete range of sizes from small, entry-level machines to large mainframes. The design distinguished between architecture and implementation, allowing IBM to release a suite of compatible designs at different prices.
Mainframe computerA mainframe computer, informally called a mainframe, maxicomputer, or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise resource planning, and large-scale transaction processing.
8-bit computingComputer architecture bit width Computer architecture bit widths Bit 1481216182426303132364045486064128256512bit slicing Application 8163264 Binary floating-point precision 16 (×½)2432 (×1)4064 (×2)80128 (×4)256 (×8) Decimal floating-point precision 3264128 vte In computer architecture, 8-bit integers or other data units are those that are 8 bits wide (1 octet).
EndiannessIn computing, endianness is the order in which bytes within a word data type are transmitted over a data communication medium or addressed in computer memory, counting only byte significance. Endianness is primarily expressed as big-endian (BE) or little-endian (LE). Computers store information in various-sized groups of binary bits. Each group is assigned a number, called its address, that the computer uses to access that data.
32-bit computing32-bit computing refers to computer architectures with a processor, memory, and other major components that operate on 32-bit units of data. Compared to smaller bit widths, 32-bit computers can perform large calculations more efficiently and process more data per clock cycle. From the 1980s to about 2006, typical 32-bit personal computers had a 32-bit address bus, permitting up to 4 GiB of RAM to be accessed.*As an Amazon Associate I earn from qualifying purchases.