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Fast Loader
A fast loader is a software program for a home computer, such as the Commodore 64 or ZX Spectrum, that accelerates the speed of file loading from floppy disk or Compact Cassette, compact cassette. Floppy disks Fast loaders came about because of a discrepancy between the actual speed at which floppy drives could transfer data and the speed that was provided by the operating system's default routines. This discrepancy was most pronounced on the VIC-20 and Commodore 64. While the earlier Commodore PET series had used an industry-standard IEEE-488 Parallel port, parallel bus, this was replaced with a Commodore bus, custom Commodore Serial communication, serial bus on the VIC-20. The serial bus was intended to be nearly as fast as its predecessor, due to the use of the MOS Technology 6522, 6522 VIA as a hardware shift register on both the drive and computer. However, hardware bugs were discovered in the 6522 that prevented this function from working consistently. As a result, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Handshake (computing)
In computing, a handshake is a signal between two devices or programs, used to, e.g., authenticate, coordinate. An example is the handshaking between a hypervisor and an application in a guest virtual machine. In telecommunications, a handshake is an automated process of negotiation between two participants (example "Alice and Bob") through the exchange of information that establishes the protocols of a communication link at the start of the communication, before full communication begins. The handshaking process usually takes place in order to establish rules for communication when a computer attempts to communicate with another device. Signals are usually exchanged between two devices to establish a communication link. For example, when a computer communicates with another device such as a modem, the two devices will signal each other that they are switched on and ready to work, as well as to agree to which protocols are being used. Handshaking can negotiate parameters tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ROM Cartridge
A ROM cartridge, usually referred to in context simply as a cartridge, cart, cassette, or card, is a replaceable part designed to be connected to a consumer electronics device such as a home computer, video game console or, to a lesser extent, electronic musical instruments. Read-Only Memory, ROM cartridges allow users to rapidly load and access programs and data alongside a floppy drive in a home computer; in a video game console, the cartridges are standalone. At the time around their release, ROM cartridges provided security against Software copyunauthorised copying of software. However, the manufacturing of ROM cartridges was more expensive than floppy disks, and the storage capacity was smaller. ROM cartridges and slots were also used for various hardware accessories and enhancements. The widespread usage of the ROM cartridge in video gaming applications has led it to be often colloquially called a game cartridge. History ROM cartridges were popularized by early home ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexadecimal
Hexadecimal (also known as base-16 or simply hex) is a Numeral system#Positional systems in detail, positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbols, hexadecimal uses sixteen distinct symbols, most often the symbols "0"–"9" to represent values 0 to 9 and "A"–"F" to represent values from ten to fifteen. Software developers and system designers widely use hexadecimal numbers because they provide a convenient representation of binary code, binary-coded values. Each hexadecimal digit represents four bits (binary digits), also known as a nibble (or nybble). For example, an 8-bit byte is two hexadecimal digits and its value can be written as to in hexadecimal. In mathematics, a subscript is typically used to specify the base. For example, the decimal value would be expressed in hexadecimal as . In programming, several notations denote hexadecimal numbers, usually involving a prefi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interrupt Vector
An interrupt vector table (IVT) is a data structure that associates a list of interrupt handlers with a list of interrupt requests in a table of interrupt vectors. Each entry of the interrupt vector table, called an interrupt vector, is the address of an interrupt handler (also known as Interrupt_handler, ISR). While the concept is common across processor architectures, IVTs may be implemented in architecture-specific fashions. For example, a dispatch table is one method of implementing an interrupt vector table. Background Most processors have an interrupt vector table, including chips from Intel, AMD, Infineon Technologies, Infineon, Microchip AVR microcontrollers, Atmel, NXP, ARM architecture, ARM, etc. Interrupt handlers Handling methods An interrupt vector table is used in the three most popular methods of finding the starting address of the interrupt service routine: "Predefined" The "predefined" method loads the program counter (PC) directly with the address of some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video Display Controller
A video display controller (VDC), also called a display engine or display interface, is an integrated circuit which is the main component in a video-signal generator, a device responsible for the production of a TV video signal in a computing or game system. Some VDCs also generate an audio signal, but that is not their main function. VDCs were used in the home computers of the 1980s and also in some early video picture systems. The VDC is the main component of the video signal generator logic, responsible for generating the timing of video signals such as the horizontal and vertical synchronization signals and the blanking interval signal. Sometimes other supporting chips were necessary to build a complete system, such as RAM to hold pixel data, ROM to hold character fonts, or some discrete logic such as shift registers. Most often the VDC chip is completely integrated in the logic of the main computer system, (its video RAM appears in the memory map of the main CPU), ... [...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 6567/6566/8562/8564 (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 Commodore 128 home computers. Succeeding the original MOS Technology VIC used in the VIC-20, the VIC-II was one of the key custom chips in the Commodore 64 (the other being the MOS Technology 6581 sound chip). Development history The VIC-II chip was designed primarily by Albert 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byte
The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit of memory in many computer architectures. To disambiguate arbitrarily sized bytes from the common 8-bit definition, network protocol documents such as the Internet Protocol () refer to an 8-bit byte as an octet. Those bits in an octet are usually counted with numbering from 0 to 7 or 7 to 0 depending on the bit endianness. The size of the byte has historically been hardware-dependent and no definitive standards existed that mandated the size. Sizes from 1 to 48 bits have been used. The six-bit character code was an often-used implementation in early encoding systems, and computers using six-bit and nine-bit bytes were common in the 1960s. These systems often had memory words of 12, 18, 24, 30, 36, 48, or 60 bits, corresponding t ... [...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] |
Bit-banging
Bit banging is a term of art that describes a method of digital data transmission as using general-purpose input/output (GPIO) instead of computer hardware that is intended specifically for data communication. Controlling software is responsible for satisfying protocol requirements including timing which can be challenging due to limited host system resources and competing demands on the software. In contrast, dedicated communication hardware (e.g., UART, SPI, I²C) satisfies protocol requirements which tends to reduce the runtime load on the controlling system software and its host processor. In particular, some communication hardware provides data buffering to lower the runtime load of the controlling system. The bit banging method may allow a computer to support a protocol with limited or no hardware changes and therefore bit banging can be a lower cost option since changing software is typically less expensive than changing hardware. Bit banging is commonly used in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore 1571
The Commodore 1571 is Commodore's high-end 5¼" floppy disk drive, announced in the summer of 1985. With its double-sided drive mechanism, it has the ability to use double-sided, double-density (DS/DD) floppy disks, storing a total of 360 kB per floppy. It also implemented a "burst mode" that improved transfer speeds, helping address the very slow performance of previous Commodore drives. Earlier Commodore drives used a custom group coded recording format that stored 170 kB per side of a disk. This made it fairly competitive in terms of storage, but limited it to only reading and writing disks from other Commodore machines. The 1571 was designed to partner with the new Commodore 128 (C128), which introduced support for CP/M. Adding double-density MFM encoding allowed the drive to read and write contemporary CP/M disks (and many others). In contrast to its single-sided predecessors, the 1541 and the briefly-available 1570, the 1571 can use both sides of the disk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore 128
The Commodore 128, also known as the C128, is the last 8-bit home computer that was commercially released by Commodore Business Machines (CBM). Introduced in January 1985 at the CES in Las Vegas, it appeared three years after its predecessor, the Commodore 64, the bestselling computer of the 1980s. Approximately 2.5 million C128s were sold during its four-year production run. The C128 is a significantly expanded successor to the C64, with nearly full compatibility. It is housed in a redesigned case with an improved keyboard including a numeric keypad and function keys. Memory was enlarged to 128 KB of RAM in two 64 KB banks. A separate graphics chip provided 80-column color video output in addition to the original C64 modes. It also included a Zilog Z80 CPU which allows the C128 to run CP/M, as an alternative to the usual Commodore BASIC environment. The huge CP/M software library, coupled with the C64's software library, gave the C128 one of the broadest ranges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
