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

Enumerate the process of dynamic modelling:, Define the Process of dynamic ...

Define the Process of dynamic modelling: Analyse applicability of actions Recognize object states Create dynamic model diagram Express every state in terms o

Induction that your closed formula , Show by induction that your closed for...

Show by induction that your closed formula from (c) is the number of times that the given statement is implemented for a problem of size n.Note: if your proof is easily  a proof th

Define about abstraction- object oriented systems, Define about Abstractio...

Define about Abstraction-  object oriented systems Abstraction is one of the most important ideas of object oriented systems Abstraction focus on the necessary, inherent aspec

What is a path name, What is a path name?  A pathname is the path from ...

What is a path name?  A pathname is the path from the root by all subdirectories to a specified file. In a two-level directory structure a user name and a file name describe a

Explain what the difference between the two readings, The following sentenc...

The following sentences have a (potential) scope ambiguity. Give two translations into predicate logic for each sentence (one formula for each reading), and explain in words what t

What is public key cryptography, What is Public Key Cryptography? Pub...

What is Public Key Cryptography? Public-key cryptography is a type of modern cryptography that allows users to communicate safely without any previously agreeing on a shared

What are difference between mealy and moore state machine, What are differe...

What are difference between Mealy and Moore state machine? Difference between Mealy and Moore state machine: 1) Mealy and Moore models are the fundamental models of state ma

What do you mean by single construct in fortan, Q. What do you mean by Sing...

Q. What do you mean by Single Construct in FORTAN? Single construct specifies the associated structured block is executed by just one thread in team (not essentially the master

Micro-operation concepts, We have determined the general architecture and r...

We have determined the general architecture and register set of MIPS microprocessor. Our subsequent task is to look at functionality of ALU, the CU and how an instruction is execut

Control unit (cu)-array processing, Control Unit (CU)  : Every PEs are unde...

Control Unit (CU)  : Every PEs are under the control of one control unit. CU controls the inter communication among the PEs. There is a local memory of CU also known as CY memory.

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