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Programmed Input–output
Programmed input–output (also programmable input/output, programmed input/output, programmed I/O, PIO) is a method of data transmission, via input/output (I/O), between a central processing unit (CPU) and a peripheral device, such as a Parallel ATA storage device. Each data item transfer is initiated by an instruction in the program, involving the CPU for every transaction. In contrast, in direct memory access (DMA) operations, the CPU is uninvolved in the data transfer. The term can refer to either memory-mapped I/O (MMIO) or port-mapped I/O (PMIO). PMIO refers to transfers using a special address space outside of normal memory, usually accessed with dedicated instructions, such as IN and OUT in x86 architectures. MMIO refers to transfers to I/O devices that are mapped into the normal address space available to the program. PMIO was very useful for early microprocessors with small address spaces, since the valuable resource was not consumed by the I/O devices. The best known ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Transmission
Data communication, including data transmission and data reception, is the transfer of data, signal transmission, transmitted and received over a Point-to-point (telecommunications), point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication using radio spectrum, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal. ''Analog transmission'' is a method of conveying voice, data, image, signal or video information using a continuous signal that varies in amplitude, phase, or some other property in proportion to that of a variable. The messages are either represented by a sequence of pulses by means of a line code (''baseband transmission''), or by a limited set of continuously varying waveforms (''passband transmission''), using a digital modulation method. The passband modulation and cor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embedded System
An embedded system is a specialized computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is embedded as part of a complete device often including electrical or electronic hardware and mechanical parts. Because an embedded system typically controls physical operations of the machine that it is embedded within, it often has real-time computing constraints. Embedded systems control many devices in common use. , it was estimated that ninety-eight percent of all microprocessors manufactured were used in embedded systems. Modern embedded systems are often based on microcontrollers (i.e. microprocessors with integrated memory and peripheral interfaces), but ordinary microprocessors (using external chips for memory and peripheral interface circuits) are also common, especially in more complex systems. In either case, the processor(s) us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interrupt
In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, the processor will suspend its current activities, save its state, and execute a function called an '' interrupt handler'' (or an ''interrupt service routine'', ISR) to deal with the event. This interruption is often temporary, allowing the software to resume normal activities after the interrupt handler finishes, although the interrupt could instead indicate a fatal error. Interrupts are commonly used by hardware devices to indicate electronic or physical state changes that require time-sensitive attention. Interrupts are also commonly used to implement computer multitasking and system calls, especially in real-time computing. Systems that use interrupts in these ways are said to be interrupt-driven. History Hardware interrupts wer ... [...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] |
WDMA (computer)
The Word DMA (WDMA) interface is a method for transferring data between a computer (through an Advanced Technology Attachment (ATA) controller) and an ATA device; it was the fastest method until Ultra Direct Memory Access (UDMA) was implemented. Single/Multiword DMA took over from programmed input/output (PIO) as the choice of interface between ATA devices and the computer. The WDMA interface is grouped into different modes. In single transfer mode, only one word (16-bit) will be transferred between the device and the computer before returning control to the CPU, and later it will repeat this cycle even if the DMA request line is continuously asserted, allowing the CPU to process data while data is transferred. This kind of transfer is implemented as "single mode transfer" in the Intel 8237 DMA controller. In multiword transfer mode, once a transfer has begun it will continue until all words are transferred or the drive negates the DMA request line. This mode is implemented as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BIOS
In computing, BIOS (, ; Basic Input/Output System, also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is a type of firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the booting process (power-on startup). The firmware comes pre-installed on the computer's motherboard. The name originates from the Basic Input/Output System used in the CP/M operating system in 1975. The BIOS firmware was originally proprietary to the IBM PC; it was reverse engineered by some companies (such as Phoenix Technologies) looking to create compatible systems. The interface of that original system serves as a ''de facto'' standard. The BIOS in older PCs initializes and tests the system hardware components ( power-on self-test or POST for short), and loads a boot loader from a mass storage device which then initializes a kernel. In the era of DOS, the BIOS provided BIOS interrupt calls for the keyboard, display, st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motherboard
A motherboard, also called a mainboard, a system board, a logic board, and informally a mobo (see #Nomenclature, "Nomenclature" section), is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It holds and allows communication between many of the crucial electronic components of a system, such as the central processing unit (CPU) and computer memory, memory, and provides connectors for other peripherals. Unlike a backplane, a motherboard usually contains significant sub-systems, such as the CPU, the chipset's input/output and Memory controller, memory controllers, interface (computing), interface connectors, and other components integrated for general use. Nomenclature ''Oxford English Dictionary'' traces the origin of the word ''motherboard'' to 1965, its earliest-found attestation occurring in the magazine ''Electronics (magazine), Electronics''. The term alludes to its importance and size compared to the components attached to i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hard Disk Drive
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating hard disk drive platter, platters coated with magnetic material. The platters are paired with disk read-and-write head, magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual Block (data storage), blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small disk enclosure, rectangular box. Hard disk drives were introduced by IBM in 1956, and were the dominant secondary storage device for History of general-purpose CPUs, general-purpose computers beginning in the early 1960s. HDDs maintained this position into the modern er ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Memory Access
Direct memory access (DMA) is a feature of computer systems that allows certain hardware subsystems to access main system computer memory, memory independently of the central processing unit (CPU). Without DMA, when the CPU is using programmed input/output, it is typically fully occupied for the entire duration of the read or write operation, and is thus unavailable to perform other work. With DMA, the CPU first initiates the transfer, then it does other operations while the transfer is in progress, and it finally receives an interrupt from the DMA controller (DMAC) when the operation is done. This feature is useful at any time that the CPU cannot keep up with the rate of data transfer, or when the CPU needs to perform work while waiting for a relatively slow I/O data transfer. Many hardware systems use DMA, including disk drive controllers, graphics cards, network cards and sound cards. DMA is also used for intra-chip data transfer in some multi-core processors. Computers that h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AT Attachment
Parallel ATA (PATA), originally , also known as Integrated Drive Electronics (IDE), is a standard interface designed for IBM PC-compatible computers. It was first developed by Western Digital and Compaq in 1986 for compatible hard drives and CD or DVD drives. The connection is used for storage devices such as hard disk drives, floppy disk drives, optical disc drives, and tape drives in computers. The standard is maintained by the X3/INCITS committee. It uses the underlying (ATA) and Packet Interface ( ATAPI) standards. The Parallel ATA standard is the result of a long history of incremental technical development, which began with the original AT Attachment interface, developed for use in early PC AT equipment. The ATA interface itself evolved in several stages from Western Digital's original Integrated Drive Electronics (IDE) interface. As a result, many near-synonyms for ATA/ATAPI and its previous incarnations are still in common informal use, in particular Extended ID ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1 E-9 S
A nanosecond (ns) is a unit of time in the International System of Units (SI) equal to one billionth of a second, that is, of a second, or seconds. The term combines the SI prefix ''nano-'' indicating a 1 billionth submultiple of an SI unit (e.g. nanogram, nanometre, etc.) and ''second'', the primary unit of time in the SI. A nanosecond is to one second, as one second is to approximately 31.69 years. A nanosecond is equal to 1000 picoseconds or microsecond. Time units ranging between 10 and 10 seconds are typically expressed as tens or hundreds of nanoseconds. Time units of this granularity are commonly found in telecommunications, pulsed lasers, and related aspects of electronics. Common measurements * 0.001 nanoseconds – one picosecond * 0.96 nanoseconds – 100 Gigabit Ethernet Interpacket gap * 96 nanoseconds – Gigabit Ethernet Interpacket gap * 1.0 nanosecond – cycle time of an electromagnetic wave with a frequency of 1 GHz (). * 1.0 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CompactFlash
CompactFlash (CF) is a flash memory mass storage device used mainly in portable electronic devices. The format was specified and the devices were first manufactured by SanDisk in 1994. CompactFlash became one of the most successful of the early memory card formats, surpassing Miniature Card and SmartMedia. Subsequent formats, such as MMC/ SD, various Memory Stick formats, and xD-Picture Card offered stiff competition. Most of these cards are smaller than CompactFlash while offering comparable capacity and speed. Proprietary memory card formats for use in professional audio and video, such as P2 and SxS, are faster, but physically larger and more costly. CompactFlash's popularity is declining as CFexpress is taking over. As of 2022, both Canon and Nikon's newest high end cameras, e.g. the Canon EOS R5, Canon EOS R3, and Nikon Z 9 use CFexpress cards for the higher performance required to record 8K video. Traditional CompactFlash cards use the Parallel ATA interf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
