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

Decimal equivalent of hex number 1A53, What is the decimal equivalent of he...

What is the decimal equivalent of hex number 1A53 ? Ans. 6739 is the decimal equivalent of Hex Number 1A53. From Hex Number to Decimal Number conversion is shown below: 1

Find out data changing from special code to temporal code, Data can be chan...

Data can be changed from special code to temporal code by using ? Ans. By using Shift Registers data can be changed from special code to temporal code. A Register wherein data ge

Explain isdn address structure and its working, Draw the ISDN address struc...

Draw the ISDN address structure and explain how the addressing works? Address Structure: The ISDN address structure is demonstrated in figure. ISDN number part has a maximum

Pre-os and runtime sub-os functionality, In a raw Itanium, a 'Processor Abs...

In a raw Itanium, a 'Processor Abstraction Layer' (PAL) is incorporated in system. When it's booted PAL is loaded in the CPU and provides a low-level interface which abstracts a nu

Steps in building the structure chart, Steps in Building the Structure Char...

Steps in Building the Structure Chart 1. Recognize top level modules and decompose them into lower levels 2. Add control connections 3. Add couples 4. Review and revis

what is feram?, Ferroelectric RAM is a random-access memory same in constr...

Ferroelectric RAM is a random-access memory same in construction to DRAM but uses a ferroelectric layer rather of a dielectric layer to achieve non-volatility. FeRAM is one of a gr

Name at least six file extensions of microsoft access, Some of the file ext...

Some of the file extensions present in MS Access are ? Access blank project template .adn ? Access database .accdb ? Access Workgroup .mdw ? Access project .adp ? A

Explain what are design patterns, Design Patterns are easy and elegant solu...

Design Patterns are easy and elegant solutions of commonly having problems in software design. Design Patterns make it simpler to reuse successful designs and architectures of expe

Chemistry, what are the applications of photochemistry?

what are the applications of photochemistry?

Write policy of cache memory, Q. Write Policy of cache memory? If conte...

Q. Write Policy of cache memory? If contents of a block in cache are changed then it's essential to write it back to main memory before replacing it. Write policy determines wh

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