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

What is software quality assuranc, Software QA includes the whole software ...

Software QA includes the whole software development PROCESS - improving and monitoring the process, making sure that any agreed-upon standards and processes are followed, and ensur

How to change default drive in dos, Q. How to Change Default Drive in dos? ...

Q. How to Change Default Drive in dos? To modify a default drive type the new drive letter followed by colon (:) and then press Enter.  For example, if the default drive is A a

Depth first search - artificial intelligence, Depth First Search - artifici...

Depth First Search - artificial intelligence: Depth first search is very similar to breadth first, except for that the things are added to the top of this agenda rather than o

What is non-volatile bios, Nonvolatile BIOS memory refers to a small memory...

Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to kept BIOS settings. It was traditionally known as CMOS RAM because it used a volatile, low-power

Optical resolution of scanner, Optical resolution or hardware resolution is...

Optical resolution or hardware resolution is mechanical limit on resolution of Scanner. For scanning the sensor has to advance after every line it scans. Smallness of this advancem

Hardware implementation for signed-magnitude data, Hardware Implementation ...

Hardware Implementation for signed-magnitude data When multiplication  is  implemented  in  digital  computer,  we  change  process lightly. Here, in place of providing registe

Process of world wide web, Q. Process of World Wide Web? When you type ...

Q. Process of World Wide Web? When you type a URL in a web browser, this is what happens: 1. If URL contains a domain name, browser first connects to a domain name server an

NETWORK ADMIN, Discuss the risks of having a single root user and how more ...

Discuss the risks of having a single root user and how more limited management abilities can be given to others users on Linux/UNIX systems.uestion #Minimum 100 words accepted#

How do you turn off cookies for one page in your site, How do you turn off ...

How do you turn off cookies for one page in your site?  Use the Cookie. Abandon Property which Gets or sets the discard flag set by the server. When true, this property instruc

Network topology, According to the report, network 1 and network 2 are not ...

According to the report, network 1 and network 2 are not able to reach network 3. As shown on OTBNetwork Topology above, OTB Inc. has 2 routing protocols running due transition iss

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