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

Polishing game, Byteland county is very famous for luminous jewels. Luminou...

Byteland county is very famous for luminous jewels. Luminous jewels are used in making beautiful necklaces. A necklace consists of various luminous jewels of particular colour. Nec

the bias and standard error , A random variable (X) is modelled as an expo...

A random variable (X) is modelled as an exponentially distributed with mean 30 units. Simulate N = 50 samples from this distribution, and every sample must have m = 20 simulated va

Loop level-parallelism based on granularity size, Loop Level This is...

Loop Level This is one more level of parallelism where iterative loop instructions can be parallelized. Fine Granularity  size is used at this level also. Simple loops in a

What is register set, What is Register Set Register Set:  Register set ...

What is Register Set Register Set:  Register set is used to keep immediate data during the implementation of instruction. This area of processor having of various registers.

Explain automated and manual systems, Q. Explain Automated and Manual syste...

Q. Explain Automated and Manual systems? Automated and Manual systems: The system that doesn't need human intervention is known as'Automated system'. In this system whole proce

Show packing and unpacking data, Q. Show Packing and Unpacking Data? P...

Q. Show Packing and Unpacking Data? Packing and Unpacking Data  pvm_packs - Pack active message buffer with arrays of prescribed data type: int info = pvm_pac

What is managed bean or mbean, A managed bean - sometimes simply referred t...

A managed bean - sometimes simply referred to as an MBean - is a type of JavaBean, developed with dependency injection. Managed Beans are particularly used in the Java Management E

Average access time experienced by the processor, Give the formula for the ...

Give the formula for the average access time experienced by the processor in a system with 2 levels of caches. Ans: Formula is for the average access time experienced by the pr

Explain the significance of encryption, Problem: (i) What are the main...

Problem: (i) What are the main threats that an organisation holding sensitive data, such as Public Data, on computer storage must guard against? (ii) To protect such data,

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