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

Units of artificial neural networks, Units of artificial neural networks: ...

Units of artificial neural networks: However the input units simply output the value that was input to them from the example to be propagated. So every other unit in a network

Explain protection mechanism, Explain Protection mechanism. Protection...

Explain Protection mechanism. Protection mechanism: The subsequent mechanisms are commonly utilized for protecting files having programs and data. (a) Access controls list

What are value types and reference types, What are value types and referenc...

What are value types and reference types?  Value type - bool, byte, chat, decimal, double, enum, float, int, long, sbyte, short, strut, uint, ulong, ushort. Value types are sto

What kind of system do we need to run gimp, Any system able of run Gnome 2,...

Any system able of run Gnome 2, KDE 3.2, Windows 2000, Mac OS X and later versions should be capable to run GIMP. GIMP's biggest appetite is for memory and how much you will requir

What are the major components of a web browser, What are the major componen...

What are the major components of a web browser? A browser contains a set of clients, a controller and a set of interpreters which manages them. All browsers must have an HTML

Defined for a push button fields in the screen attributes, What is to be de...

What is to be defined for a push button fields in the screen attributes? A function code has to be described in the screen attributes for the push buttons in a screen.

Minimization of the logic function using NORgates, Minimize the logic funct...

Minimize the logic function F(A, B, C, D) = ∑ m(1,3,5,8,9,11,15) + d(2,13) using NOR gates with help of K-map. Ans. Realization of given expression by using NOR gates: In POS

Student, Suppose we have an array-based list A[0..N - 1] and we want to del...

Suppose we have an array-based list A[0..N - 1] and we want to delete all duplicates. LastPosition is initially N - 1, but gets smaller as elements are deleted. Consider the pseudo

Classification based on grain size, Classification Based On Grain Size ...

Classification Based On Grain Size  This classification is based on identifying  the parallelism in a program to be implemented on a multiprocessor system. The plan is to recog

Starting parallel virtual machine, Q. Starting parallel virtual machine? ...

Q. Starting parallel virtual machine? To initialize PVM on any host on that PVM has been installed we can type  % pvm The PVM console known as pvm is a standalone PVM t

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