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Gigatron TTL
The Gigatron TTL is a retro-style 8-bit computer, where the CPU is implemented by a set of TTL chips instead of a single microprocessor, imitating the hardware present in early arcades. Its target is the computing enthusiasts, for studying or hobby purposes. Architecture The CPU is implemented through a small set of TTL 7400 series chips, running at 6.25 MHz base clock rate, that achieve a faster clock speed by providing better chips. RAM can also be increased in the same way. Three CPU modes are implemented: *8-bit native assembly code, that implements a Harvard architecture. This mode offers 17 instructions and has room for up to 256 instructions: 8 ALU operations * 8 addressing modes * 4 bus modes. The ROM firmware and the vCPU interpreter are written in the 8-bit native assembly code. *16-bit vCPU interpreter, that implements a von Neumann architecture and has 34 instructions. It loads and runs programs from RAM. The integrated programs are written for this vCPU. ...
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Computer
A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic sets of operations known as Computer program, ''programs'', which enable computers to perform a wide range of tasks. The term computer system may refer to a nominally complete computer that includes the Computer hardware, hardware, operating system, software, and peripheral equipment needed and used for full operation; or to a group of computers that are linked and function together, such as a computer network or computer cluster. A broad range of Programmable logic controller, industrial and Consumer electronics, consumer products use computers as control systems, including simple special-purpose devices like microwave ovens and remote controls, and factory devices like industrial robots. Computers are at the core of general-purpose devices ...
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Clock Rate
Clock rate or clock speed in computing typically refers to the frequency at which the clock generator of a processor can generate pulses used to synchronize the operations of its components. It is used as an indicator of the processor's speed. Clock rate is measured in the SI unit of frequency hertz (Hz). The clock rate of the first generation of computers was measured in hertz or kilohertz (kHz), the first personal computers from the 1970s through the 1980s had clock rates measured in megahertz (MHz). In the 21st century the speed of modern CPUs is commonly advertised in gigahertz (GHz). This metric is most useful when comparing processors within the same family, holding constant other features that may affect performance. Determining factors Binning Manufacturers of modern processors typically charge higher prices for processors that operate at higher clock rates, a practice called binning. For a given CPU, the clock rates are determined at the end of the manufact ...
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Video
Video is an Electronics, electronic medium for the recording, copying, playback, broadcasting, and display of moving picture, moving image, visual Media (communication), media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems, which, in turn, were replaced by flat-panel displays of several types. Video systems vary in display resolution, Display aspect ratio, aspect ratio, refresh rate, color capabilities, and other qualities. Analog and digital variants exist and can be carried on a variety of media, including radio broadcasts, magnetic tape, optical discs, Video file format, computer files, and Streaming media, network streaming. Etymology The word ''video'' comes from the Latin verb ''video,'' meaning to see or ''videre''. And as a noun, "that which is displayed on a (television) screen," History Analog video Video developed from facsimile systems developed in the mid-19th century. Early mecha ...
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Machine Code
In computer programming, machine code is computer code consisting of machine language instructions, which are used to control a computer's central processing unit (CPU). For conventional binary computers, machine code is the binaryOn nonbinary machines it is, e.g., a decimal representation. representation of a computer program that is actually read and interpreted by the computer. A program in machine code consists of a sequence of machine instructions (possibly interspersed with data). Each machine code instruction causes the CPU to perform a specific task. Examples of such tasks include: # Load a word from memory to a CPU register # Execute an arithmetic logic unit (ALU) operation on one or more registers or memory locations # Jump or skip to an instruction that is not the next one In general, each architecture family (e.g., x86, ARM) has its own instruction set architecture (ISA), and hence its own specific machine code language. There are exceptions, such as the ...
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MOS Technology 6502
The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit computing, 8-bit microprocessor that was designed by a small team led by Chuck Peddle for MOS Technology. The design team had formerly worked at Motorola on the Motorola 6800 project; the 6502 is essentially a simplified, less expensive and faster version of that design. When it was introduced in 1975, the 6502 was the least expensive microprocessor on the market by a considerable margin. It initially sold for less than one-sixth the cost of competing designs from larger companies, such as the 6800 or Intel 8080. Its introduction caused rapid decreases in pricing across the entire processor market. Along with the Zilog Z80, it sparked a series of projects that resulted in the home computer microcomputer revolution, revolution of the early 1980s. Home video game consoles and home com ...
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Random-access Memory
Random-access memory (RAM; ) is a form of Computer memory, electronic computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A random-access memory device allows data items to be read (computer), 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 data storage, 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 MOSFET, MOS (metal–oxide–semiconductor) Memory cell (computing), memory cells. RAM is normally associated with Volatile memory, volatile types of memory where s ...
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Von Neumann Architecture
The von Neumann architecture—also known as the von Neumann model or Princeton architecture—is a computer architecture based on the '' First Draft of a Report on the EDVAC'', written by John von Neumann in 1945, describing designs discussed with John Mauchly and J. Presper Eckert at the University of Pennsylvania's Moore School of Electrical Engineering. The document describes a design architecture for an electronic digital computer made of "organs" that were later understood to have these components: * A processing unit with both an arithmetic logic unit and processor registers * A control unit that includes an instruction register and a program counter * Memory that stores data and instructions * External mass storage * Input and output mechanisms.. The attribution of the invention of the architecture to von Neumann is controversial, not least because Eckert and Mauchly had done a lot of the required design work and claim to have had the idea for stored programs ...
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Firmware
In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and softw ..., firmware is software that provides low-level control of computing device Computer hardware, hardware. For a relatively simple device, firmware may perform all control, monitoring and data manipulation functionality. For a more complex device, firmware may provide relatively low-level control as well as hardware abstraction Service (systems architecture), services to higher-level software such as an operating system. Firmware is found in a wide range of computing devices including personal computers, smartphones, home appliances, vehicles, computer peripherals and in many of the integrated circuits inside each of these larger systems. Firmware is stored in non-volatile memory either read-only memory (ROM) or progra ...
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Read-only Memory
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing software that is rarely changed during the life of the system, also known as firmware. Software applications, such as video games, for programmable devices can be distributed as ROM cartridge, plug-in cartridges containing ROM. Strictly speaking, ''read-only memory'' refers to hard-wired memory, such as diode matrix or a #Solid-state ROM, mask ROM integrated circuit (IC), that cannot be electronically changed after manufacture. Although discrete circuits can be altered in principle, through the addition of Jump wire, bodge wires and the removal or replacement of components, ICs cannot. Correction of errors, or updates to the software, require new devices to be manufactured and to replace the installed device. Floating-gate ROM semiconductor ...
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Bus (computing)
In computer architecture, a bus (historically also called a data highway or databus) is a communication system that transfers Data (computing), data between components inside a computer or between computers. It encompasses both Computer hardware, hardware (e.g., wires, optical fiber) and software, including communication protocols. At its core, a bus is a shared physical pathway, typically composed of wires, traces on a circuit board, or busbars, that allows multiple devices to communicate. To prevent conflicts and ensure orderly data exchange, buses rely on a communication protocol to manage which device can transmit data at a given time. Buses are categorized based on their role, such as system buses (also known as internal buses, internal data buses, or memory buses) connecting the Central processing unit, CPU and Computer memory, memory. Expansion buses, also called peripheral buses, extend the system to connect additional devices, including peripherals. Examples of widely ...
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Addressing Mode
Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a given instruction set architecture define how the machine language instructions in that architecture identify the operand(s) of each instruction. An addressing mode specifies how to calculate the effective memory address of an operand by using information held in registers and/or constants contained within a machine instruction or elsewhere. In computer programming, addressing modes are primarily of interest to those who write in assembly languages and to compiler writers. For a related concept see orthogonal instruction set which deals with the ability of any instruction to use any addressing mode. Caveats There are no generally accepted names for addressing modes: different authors and computer manufacturers may give different names to the same addressing mode, or the same names to different addressing modes. F ...
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Arithmetic Logic Unit
In computing, an arithmetic logic unit (ALU) is a Combinational logic, combinational digital circuit that performs arithmetic and bitwise operations on integer binary numbers. This is in contrast to a floating-point unit (FPU), which operates on floating point numbers. It is a fundamental building block of many types of computing circuits, including the central processing unit (CPU) of computers, FPUs, and graphics processing units (GPUs). The inputs to an ALU are the data to be operated on, called operands, and a code indicating the operation to be performed (opcode); the ALU's output is the result of the performed operation. In many designs, the ALU also has status inputs or outputs, or both, which convey information about a previous operation or the current operation, respectively, between the ALU and external status registers. Signals An ALU has a variety of input and output net (electronics), nets, which are the electrical conductors used to convey Digital signal (electroni ...
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