Search results
Results From The WOW.Com Content Network
The CPU of a system that uses channel I/O typically has only one machine instruction in its repertoire for input and output; this instruction is used to pass input/output commands to the specialized I/O hardware in the form of channel programs. I/O thereafter proceeds without intervention from the CPU until an event requiring notification of ...
The Intel 8089 input/output coprocessor was available for use with the 8086/8088 central processor. It was announced in May 1979, but the price was not available at that time. [ 1 ] It used the same programming technique as 8087 for input/output operations, such as transfer of data from memory to a peripheral device, and so reducing the load on ...
The Mano machine is a computer theoretically described by M. Morris Mano.It contains a central processing unit, random access memory, and an input-output bus.Its limited instruction set and small address space limit it to use as a microcontroller, but it can easily be expanded to have a 32-bit accumulator register, and 28-bit addressing using a hardware description language like Verilog or ...
Memory-mapped I/O is preferred in IA-32 and x86-64 based architectures because the instructions that perform port-based I/O are limited to one register: EAX, AX, and AL are the only registers that data can be moved into or out of, and either a byte-sized immediate value in the instruction or a value in register DX determines which port is the source or destination port of the transfer.
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, [1] such as a Parallel ATA storage device. Each data item transfer is initiated by an instruction in the program ...
The mainframe would not require any I/O processing at all, instead would just set parameters for an input or output operation and then signal the channel processor to carry out the whole of the operation. By dedicating relatively simple sub-processors to handle time-consuming I/O formatting and processing, overall system performance was improved.
An alternative method is via instruction-based I/O which requires that a CPU have specialized instructions for I/O. [1] Both input and output devices have a data processing rate that can vary greatly. [2] With some devices able to exchange data at very high speeds direct access to memory (DMA) without the continuous aid of a CPU is required. [2]
In the original S/360 and S/370 architectures, each processor had its own set of I/O channels and addressed I/O devices with a 12-bit cuu address, containing a 4-bit channel number and an 8-bit unit (device) number to be sent on the channel bus in order to select the device; the operating system had to be configured to reflect the processor and cuu address for each device.