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PEEK And POKE
In computing, PEEK and POKE are commands used in some high-level programming languages for accessing the contents of a specific memory cell referenced by its memory address. PEEK gets the byte located at the specified memory address. POKE sets the memory byte at the specified address. These commands originated with machine code monitors such as the DECsystem-10 monitor; these commands are particularly associated with the BASIC programming language, though some other languages such as Pascal and COMAL also have these commands. These commands are comparable in their roles to pointers in the C language and some other programming languages. One of the earliest references to these commands in BASIC, if not the earliest, is in Altair BASIC. DIM W% 4 : REM reserve 4 bytes of memory, pointed to by integer variable W% > ?W% = 42 : REM store constant 42; equivalent of 'POKE W%, 42' > PRINT ?W% : REM print the byte pointed to by W%; equivalent of 'PRINT PEEK(W%)' 42 32-bit va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monitor Commodore CBM 3016 With BASIC Program-0309
Monitor or monitor may refer to: Places * Monitor, Alberta * Monitor, Indiana, town in the United States * Monitor, Kentucky * Monitor, Oregon, unincorporated community in the United States * Monitor, Washington * Monitor, Logan County, West Virginia * Monitor, Monroe County, West Virginia * Loope, California, formerly Monitor Arts, entertainment, and media Fictional characters * Monitor (Mar Novu), a DC comics character * Monitors (DC Comics), a group of fictional comic book characters, who appear in books published by DC Comics Periodicals * ''Monitor'' (magazine), a weekly newsmagazine published in Podgorica, Montenegro * ''Monitor'' (Polish newspaper), an 18th-century Polish newspaper * ''Concord Monitor'', a daily newspaper in New Hampshire, United States * ''The Monitor'' (Sydney), a biweekly newspaper published between 1826 and 1841 * '' Daily Monitor'', a Ugandan newspaper Television * ''Monitor'' (UK TV programme), a BBC arts programme which aired from 1958 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Expression (programming)
In computer science, an expression is a syntactic entity in a programming language that may be evaluated to determine its value. It is a combination of one or more constants, variables, functions, and operators that the programming language interprets (according to its particular rules of precedence and of association) and computes to produce ("to return", in a stateful environment) another value. This process, for mathematical expressions, is called ''evaluation''. In simple settings, the resulting value is usually one of various primitive types, such as numerical, string, boolean, complex data type or other types. Expression is often contrasted with statement—a syntactic entity that has no value (an instruction). Examples For example, 2 + 3 is both an arithmetic and programming expression, which evaluates to 5. A variable is an expression because it denotes a value in memory, so y + 6 is also an expression. An example of a relational expression is 4 ≠ 4, which eval ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBC BASIC
BBC BASIC is a version of the BASIC programming language released in 1981 as the native programming language for the BBC Micro home/personal computer, providing a standardized language for a UK computer literacy project of the BBC. It was written mainly by Sophie Wilson. BBC BASIC, based on the older Atom BASIC for the Acorn Atom, extended contemporary microcomputer BASICs with named DEF PROC/DEF FN procedures and functions, REPEAT UNTIL loops, and IF THEN ELSE structures inspired by COMAL. The interpreter also included statements for controlling the BBC Micro's four-channel sound output and its low-/high-resolution eight-mode graphics display. Due to a number of optimizations, BBC BASIC ran programs much faster than Microsoft BASIC running on similar machines. The optimizations included using multiple linked lists for variable lookup rather than a single long list, pre-defining the location of integer variables, and having separate integer maths routines. Speed was furthe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer from cellular phones and video game consoles to web servers and supercomputers. The dominant general-purpose personal computer operating system is Microsoft Windows with a market share of around 74.99%. macOS by Apple Inc. is in second place (14.84%), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Star Computers
North Star Computers Inc. (later styled as NorthStar) was an American computer company based in Berkeley, California existing between June 1976 (when according to popular rumor it was formed as "Kentucky Fried Computers") and 1989. Originally a mail order business for IMSAI computers, it soon developed into a major player in the early microcomputer market, becoming first known for their low-cost floppy disk system for S-100 bus machines, and later for their own S-100 bus computers running either the CP/M operating system or North Star's own proprietary operating system, NSDOS. North Star BASIC was a common dialect of the popular BASIC programming language. They later expanded their lineup with dual-CPU machines able to run MS-DOS, and a server version running either DOS or Novell NetWare. While initially successful, North Star's sales suffered from the company's adherence to hard sector floppy drives which made software difficult to port onto North Star machines. It was no longer a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mapping The Atari
''Mapping the Atari'', written by Ian Chadwick and published by COMPUTE! Publications in 1983, is a location-by-location explanation of the memory layout of the Atari 8-bit family of home computers. The introduction is by Optimized Systems Software co-founder Bill Wilkinson. The book covers the 64K address space of the system's 6502 processor from low to high, including addresses used by the operating system or mapped to hardware registers, as well as how to use them. For example, location 756 (2F4) CHBAS contains the starting memory address that tells ANTIC where to find the character set. The author explains how to use this feature to build custom character sets. An updated version covering changes to the operating system and newer machines like the 130XE followed in 1985. ''Antic'' magazine serialized the book in 1989 and 1990. Reception ''The Addison-Wesley Addison-Wesley is an American publisher of textbooks and computer literature. It is an imprint of Pearson PLC, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ANTIC
Alphanumeric Television Interface Controller (ANTIC) is an LSI ASIC dedicated to generating 2D computer graphics to be shown on a television screen or computer display. Under the direction of Jay Miner, the chip was designed in 1977-1978 by Joe Decuir, Francois Michel, and Steve Smith for the Atari 8-bit family of home computers first released in 1979 and was patented by Atari, Inc. Atari, Inc. was an American video game developer and home computer company founded in 1972 by Nolan Bushnell and Ted Dabney. Atari was a key player in the formation of the video arcade and video game industry. Based primarily around the Sunny ... in 1981. ANTIC is also used in the 1982 Atari 5200 video game console, which shares most of the same hardware as the 8-bit computers. For every frame of video, ANTIC reads a program of instruction set, instructions to define the playfield, or background graphics, then delivers a data stream to the companion CTIA and GTIA, CTIA or GTIA chip which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atari 8-bit Family
The Atari 8-bit family is a series of 8-bit home computers introduced by Atari, Inc. in 1979 as the Atari 400 and Atari 800. The series was successively upgraded to Atari 1200XL , Atari 600XL, Atari 800XL, Atari 65XE, Atari 130XE, Atari 800XE, and Atari XEGS, the last discontinued in 1992. They differ primarily in packaging, each based on the MOS Technology 6502 central processing unit, CPU at and the same custom coprocessor chips. As the first home computer architecture with coprocessors, it has graphics and sound more advanced than most contemporary machines. Video games were a major draw, and first-person space combat simulator ''Star Raiders'' is considered the platform's killer app. The plug-and-play peripherals use the Atari SIO serial bus, with one developer eventually also co-patenting USB. While using the same internal technology, the Atari 800 was sold as a high-end model, while the 400 was more affordable. The 400 has a pressure-sensitive, spillproof membrane keyboar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MOS Technology VIC-II
The VIC-II (Video Interface Chip II), specifically known as the MOS Technology 6567/8562/8564 (NTSC versions), 6569/8565/8566 (PAL), is the microchip tasked with generating Y/C video signals (combined to composite video in the RF modulator) and DRAM refresh signals in the Commodore 64 and C128 home computers. Succeeding MOS's original VIC (used in the VIC-20), the VIC-II was one of the two chips mainly responsible for the C64's success (the other chip being the 6581 SID). Development history The VIC-II chip was designed primarily by Al Charpentier and Charles Winterble at MOS Technology, Inc. as a successor to the MOS Technology 6560 "VIC". The team at MOS Technology had previously failed to produce two graphics chips named ''MOS Technology 6562'' for the Commodore TOI computer, and ''MOS Technology 6564'' for the Color PET, due to memory speed constraints. In order to construct the VIC-II, Charpentier and Winterble made a market survey of current home computers and video ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore 64
The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness World Records as the highest-selling single computer model of all time, with independent estimates placing the number sold between 12.5 and 17 million units. Volume production started in early 1982, marketing in August for . Preceded by the VIC-20 and Commodore PET, the C64 took its name from its of RAM. With support for multicolor sprites and a custom chip for waveform generation, the C64 could create superior visuals and audio compared to systems without such custom hardware. The C64 dominated the low-end computer market (except in the UK and Japan, lasting only about six months in Japan) for most of the later years of the 1980s. For a substantial period (1983–1986), the C64 had between 30% and 40% share of the US market and two mil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Debugging
In computer programming and software development, debugging is the process of finding and resolving '' bugs'' (defects or problems that prevent correct operation) within computer programs, software, or systems. Debugging tactics can involve interactive debugging, control flow analysis, unit testing, integration testing, log file analysis, monitoring at the application or system level, memory dumps, and profiling. Many programming languages and software development tools also offer programs to aid in debugging, known as ''debuggers''. Etymology The terms "bug" and "debugging" are popularly attributed to Admiral Grace Hopper in the 1940s. While she was working on a Mark II computer at Harvard University, her associates discovered a moth stuck in a relay and thereby impeding operation, whereupon she remarked that they were "debugging" the system. However, the term "bug", in the sense of "technical error", dates back at least to 1878 and Thomas Edison who describes the "litt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Processor Register
A processor register is a quickly accessible location available to a computer's processor. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only. In computer architecture, registers are typically addressed by mechanisms other than main memory, but may in some cases be assigned a memory address e.g. DEC PDP-10, ICT 1900. Almost all computers, whether load/store architecture or not, load data from a larger memory into registers where it is used for arithmetic operations and is manipulated or tested by machine instructions. Manipulated data is then often stored back to main memory, either by the same instruction or by a subsequent one. Modern processors use either static or dynamic RAM as main memory, with the latter usually accessed via one or more cache levels. Processor registers are normally at the top of the memory hierarchy, and provide the fastest way to access data. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
