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

Computer organization, using one-address instructions,write a program to co...

using one-address instructions,write a program to compute X=A-BxC

Cobol coding, What is cobol codin for heap sort?

What is cobol codin for heap sort?

Determine capacity in bytes of a certain memory, A certain memory has a cap...

A certain memory has a capacity of 4K × 8 (i)  How many data input and data output lines does it have? (ii) How many address lines does it have? (iii) What is its capacity in bytes

The number of control lines for a 8 – to – 1 multiplexer, What is the numbe...

What is the number of control lines for a 8 - to - 1 multiplexer ? Ans. There are 3 control lines, for an 8 to 1 Multiplexer. The control signals are utilized to steer any one

Are there standards for electronic imaging, Are there standards for electro...

Are there standards for electronic imaging? Given the sensitive nature of most permanent records, there are microphotography standards in place which contain microfilm, compute

How address symbol table is generated, Address symbol table is generated by...

Address symbol table is generated by the  (A) memory management software.  (B) assembler.  (C) match logic of associative memory.   (D) generated by operating system

Types of software - computer architecture, Types of software: A layer ...

Types of software: A layer structure is described where Operating System is located on generally used software systems on desktops   System software System sof

Hypertext markup language, Web pages or materials which are in the form of ...

Web pages or materials which are in the form of hypermedia documents accessed through Internet can be located anywhere in world. No matter from where they originated, most Web d

Recordable cds and dvds, Optical disk becomes an attractive alternative for...

Optical disk becomes an attractive alternative for backing up information from hard disk drives and employs large text, audio and video data. Advent of CD-ROM-R and DVD-ROM-R has b

Describe the concept of aggregation, Aggregation Aggregation is a spec...

Aggregation Aggregation is a special form of association that models the "part-whole" or "a-part-of" relationship as an aggregate (the whole) and parts. The most important pro

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