|
XIOS
MP/M (Multi-Programming Monitor Control Program) is a discontinued multi-user version of the CP/M operating system, created by Digital Research developer Tom Rolander in 1979. It allowed multiple users to connect to a single computer, each using a separate terminal. MP/M was a fairly advanced operating system for its era, at least on microcomputers. It included a priority-scheduled multitasking kernel (before such a name was used, the kernel was referred to as the ''nucleus'') with memory protection, concurrent input/output (XIOS) and support for spooling and queueing. It also allowed for each user to run multiple programs, and switch between them. MP/M platforms MP/M-80 The 8-bit system required a 8080 (or Z80) CPU and a minimum of 32 KB of RAM to run, but this left little memory for user applications. In order to support reasonable setups, MP/M allowed for memory to be switched in and out of the machine's "real memory" area. So for instance a program might be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concurrent CP/M
MP/M (Multi-Programming Monitor Control Program) is a discontinued multi-user version of the CP/M operating system, created by Digital Research Digital Research, Inc. (DR or DRI) was a privately held American software company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser ... developer Tom Rolander in 1979. It allowed multiple users to connect to a single computer, each using a separate terminal. MP/M was a fairly advanced operating system for its era, at least on microcomputers. It included a priority-scheduled computer multitasking, multitasking kernel (operating system), kernel (before such a name was used, the kernel was referred to as the ''nucleus'') with memory protection, concurrent input/output (XIOS) and support for spooling and queueing. It also allowed for each user to run multiple programs, and switch between them. MP/M platforms MP/M-80 The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Research
Digital Research, Inc. (DR or DRI) was a privately held American software company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser DOS, DOS Plus, DR DOS and Graphics Environment Manager, GEM. It was the first large software company in the microcomputer world. Digital Research was originally based in Pacific Grove, California, later in Monterey, California. History 1974–1979: Founding and incorporation In 1972, Gary Kildall, an instructor at the Naval Postgraduate School in Monterey, California, began working at Intel as a consultant under the business name Microcomputer Applications Associates (MAA). By 1974, he had developed Control Program/Monitor, or CP/M, the first disk operating system for microcomputers. In 1974 he incorporated as Intergalactic Digital Research, with his wife handling the business side of the operation. The company soon began opera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BSD Licenses
BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses. BSD is both a license and a class of license (generally referred to as BSD-like). The modified BSD license (in wide use today) is very similar to the license originally used for the BSD version of Unix. The BSD license is a simple license that merely requires that all code retain the BSD license notice if redistributed in source code format, or reproduce the notice if redistributed in binary format. The BSD license (unlike some other licenses e.g. GPL) does not require that source code be distributed at all. Terms In addition to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siglum
Scribal abbreviations, or sigla (singular: siglum), are abbreviations used by ancient and medieval scribes writing in various languages, including Latin, Greek, Old English and Old Norse. In modern manuscript editing (substantive and mechanical) sigla are the symbols used to indicate the source manuscript (e.g. variations in text between different such manuscripts). History Abbreviated writing, using sigla, arose partly from the limitations of the workable nature of the materials (stone, metal, parchment, etc.) employed in record-making and partly from their availability. Thus, lapidaries, engravers, and copyists made the most of the available writing space. Scribal abbreviations were infrequent when writing materials were plentiful, but by the 3rd and 4th centuries AD, writing materials were scarce and costly. During the Roman Republic, several abbreviations, known as sigla (plural of ''siglum'' 'symbol or abbreviation'), were in common use in inscriptions, and they inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bank Switching
Bank switching is a technique used in computer design to increase the amount of usable memory beyond the amount directly addressable by the Processor (computing), processor instructions. It can be used to configure a system differently at different times; for example, a read-only memory, ROM required to booting, start a system from diskette could be switched out when no longer needed. In video game systems, bank switching allowed larger games to be developed for play on existing consoles. Bank switching originated in minicomputer systems. Many modern microcontrollers and microprocessors use bank switching to manage random-access memory, non-volatile memory, input-output devices and system management registers in small embedded systems. The technique was common in 8-bit microcomputer systems. Bank-switching may also be used to work around limitations in address bus width, where some hardware constraint prevents straightforward addition of more address lines, and to work around li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Processing Unit
A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary Processor (computing), processor in a given computer. Its electronic circuitry executes Instruction (computing), instructions of a computer program, such as arithmetic, logic, controlling, and input/output (I/O) operations. This role contrasts with that of external components, such as main memory and I/O circuitry, and specialized coprocessors such as graphics processing units (GPUs). The form, CPU design, design, and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic–logic unit (ALU) that performs arithmetic operation, arithmetic and Bitwise operation, logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the #Fetch, fetching (from memory), #Decode, decoding and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random Access Memory
Random-access memory (RAM; ) is a form of electronic computer memory that can be read and changed in any order, typically used to store working data and machine code. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory, in contrast with other direct-access data storage media (such as hard disks and magnetic tape), where the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement. In today's technology, random-access memory takes the form of integrated circuit (IC) chips with MOS (metal–oxide–semiconductor) memory cells. RAM is normally associated with volatile types of memory where stored information is lost if power is removed. The two main types of volatile random-access semiconductor memory are static ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilobyte
The kilobyte is a multiple of the unit byte for Computer data storage, digital information. The International System of Units (SI) defines the prefix ''kilo-, kilo'' as a multiplication factor of 1000 (103); therefore, one kilobyte is 1000 bytes.International Standard IEC 80000-13 Quantities and Units – Part 13: Information science and technology, International Electrotechnical Commission (2008). The internationally recommended unit symbol for the kilobyte is kB. In some areas of information technology, particularly in reference to random-access memory capacity, ''kilobyte'' instead often refers to 1024 (210) bytes. This arises from the prevalence of sizes that are powers of two in modern digital memory architectures, coupled with the coincidence that 210 differs from 103 by less than 2.5%. The kibibyte is defined as 1024 bytes, avoiding the ambiguity issues of the ''kilobyte''.International Standard IEC 80000-13 Quantities and Units – Part 13: Information scien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8080
The Intel 8080 is Intel's second 8-bit microprocessor. Introduced in April 1974, the 8080 was an enhanced successor to the earlier Intel 8008 microprocessor, although without binary compatibility.'' Electronic News'' was a weekly trade newspaper. The same advertisement appeared in the May 2, 1974, issue of ''Electronics'' magazine. Originally intended for use in embedded systems such as calculators, cash registers, computer terminals, and industrial robots, its robust performance soon led to adoption in a broader range of systems, ultimately helping to launch the microcomputer industry. Several key design choices contributed to the 8080’s success. Its 40‑pin package simplified interfacing compared to the 8008’s 18‑pin design, enabling a more efficient data bus. The transition to NMOS technology provided faster transistor speeds than the 8008's PMOS while also simplifying interfacing by making it TTL compatible. An expanded instruction set and a full 16-bit address ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Input/output
In computing, input/output (I/O, i/o, or informally io or IO) is the communication between an information processing system, such as a computer, and the outside world, such as another computer system, peripherals, or a human operator. Inputs are the signals or data received by the system and outputs are the signals or data sent from it. The term can also be used as part of an action; to "perform I/O" is to perform an input or output operation. are the pieces of hardware used by a human (or other system) to communicate with a computer. For instance, a keyboard or computer mouse is an input device for a computer, while monitors and printers are output devices. Devices for communication between computers, such as modems and network cards, typically perform both input and output operations. Any interaction with the system by an interactor is an input and the reaction the system responds is called the output. The designation of a device as either input or output depend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernel (operating System)
A kernel is a computer program at the core of a computer's operating system that always has complete control over everything in the system. The kernel is also responsible for preventing and mitigating conflicts between different processes. It is the portion of the operating system code that is always resident in memory and facilitates interactions between hardware and software components. A full kernel controls all hardware resources (e.g. I/O, memory, cryptography) via device drivers, arbitrates conflicts between processes concerning such resources, and optimizes the use of common resources, such as CPU, cache, file systems, and network sockets. On most systems, the kernel is one of the first programs loaded on startup (after the bootloader). It handles the rest of startup as well as memory, peripherals, and input/output (I/O) requests from software, translating them into data-processing instructions for the central processing unit. The critical code of the kernel is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
