Input-output techniques, Computer Engineering

Assignment Help:

After going through details of device interfaces next point to be discussed is how the interface can be used to support I/O from devices. Binary information received from an external device is generally stored in memory for later processing. Information transferred from central computer in an external device initiates in memory unit. Data transfer between central computer and I/O devices can be handled in some modes. 3 techniques are possible for I/O operation. These are:

  • Programmed input/output
  • Interrupt driven input/output
  • Direct memory access

Figure below gives an general idea of these 3 techniques:

1004_INPUT-OUTPUT TECHNIQUES.png

Figure: Overview of the three Input/ Output

In programmed I/O, I/O operations are fully controlled by processor. The processor executes a program which initiates, directs and terminate an I/O operation. It needs a little special I/O hardware however is quite time consuming for processor as processor has to wait for slower I/O operations to finish. 

With interrupt driven I/O when interface decides that device is ready for data transfer it produces an interrupt request to the computer. Upon detecting external interrupt signal processor stops the task it was processing and branches to a service program to process I/O transfer and then returns to task it was initially performing that result in waiting time by the processor being reduced.

With both interrupt-driven and programmed I/O processor is responsible for extracting data from main memory for output and storing data in main memory during input. What about having a substitute where I/O device may directly store data or retrieve data from memory? This alternative is called direct memory access (DMA). In this mode I/O interface and main memory exchange data directly without involvement of processor.

2405_INPUT-OUTPUT TECHNIQUES1.png

Figure: Three techniques of I/O


Related Discussions:- Input-output techniques

Digital systems and microprocessors, Your logic function for this assignmen...

Your logic function for this assignment is to be derived from your own student number. The number 1224583 will be used as an example as to how you should derive your function and e

Explain about cathode ray tubes, Q. Explain about Cathode Ray Tubes? Ca...

Q. Explain about Cathode Ray Tubes? Cathode ray tube is the major technology on that televisions and monitors have been based.  CRT is a partially evacuated glass tube which is

Why are interrupt masks provided in any processor, Why are interrupt masks ...

Why are interrupt masks provided in any processor? Interrupt mask enable the higher priority devices comes first and there for lower priority devices comes last. The interrupt

Perform binary addition and subtraction on two numbers, Q Develop a menu ...

Q Develop a menu driven program to perform Binary addition and subtraction on two numbers that are inputted. Check that entered numbers are in base 2 or not else error messag

Show typical microprocessor system architecture, Q. Show typical microproce...

Q. Show typical microprocessor system architecture? A microprocessor system bus consists of three physical buses: the address bus, the data bus, and the control bus. The types

Offset litho duplicating of information, Offset Litho Duplicating Equi...

Offset Litho Duplicating Equipment Required Duplicator Plate-making equipment (not always, essential), e.g. printing box and processing unit Plates Paper Ink

Features of read-only memory, Q. Features of read-only memory? ROMs are...

Q. Features of read-only memory? ROMs are memories on which it's not possible to write data when they are on-line to computer. They can only be read. This is reason why it is k

NachoS, Can I get the scheduling code for NachOS?

Can I get the scheduling code for NachOS?

Control of program, Example:                         CMP    AX,BX    ;...

Example:                         CMP    AX,BX    ; compare instruction: sets flags JE        THERE    ; if equal then skip the ADD instruction  ADD  AX, 02    ; add 02

Find out the correction to be applied in decimal adder, The correction to b...

The correction to be applied in decimal adder to the generated sum is ? Ans. 00110 is the generated sum when the correction to be applied in decimal adder. While the 4 bit su

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd