Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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:
Figure below gives an general idea of these 3 techniques:
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.
Figure: Three techniques of I/O
Aggregation Aggregation is a special form of association that models the "part-whole" or "a-part-of" relationship as an aggregate (the whole) and parts. The most important pro
What is Supply Chain Management? Supply Chain Management: Supply Chain Management includes developing the performance of an organization's supply chain from its suppliers to
What are the different between hypertext hypermedia? Hypertext is fundamentally the same like regular text; this can be stored, read or searched and edited along with a signifi
Define various security protocols used for e-commerce applications. The e-commerce systems of today are composed of very many components as like: a commerce server, client soft
The heart of an experts systems is the powerful corups of knowledge that accumulates during system building. The knowledge is explicit and organized to simplify decisio
Explain the T Flip Flop? The toggle, or T, flip-flop is the bistable device that changes state on command from a common input terminal. Truth Table
why we use void main in c progrmeing
i want to get answer about this topic what is software engineering and what is its limitation
No C don't have circular shift operator. (Part of the reason why that is the sizes of C's types aren't precisely described----but a circular shift makes most sense when applied to
Q What is Cable Modem? One more way of accessing Internet currently being developed is use of cable modems. These require that you subscribe to a cable service as well as allow
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd