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

Explain the low level language - computer programming, Explain the Low Leve...

Explain the Low Level Language - Computer Programming? An assembly language or a machine language is known as Low-level language which are closer to the hardware than are high-

State the concept of multiplicity, Multiplicity Multiplicity in an ass...

Multiplicity Multiplicity in an association specifies tells us about number of objects participate in a relationship. It decides the number of related objects. Multiplicity is

What is a reference string, What is a reference string? An algorithm is...

What is a reference string? An algorithm is evaluated by running it on a exacting string of memory references and computing the number of page faults. The string of memory refe

Explain working of telnet, Q. Explain Working of TELNET? The working o...

Q. Explain Working of TELNET? The working of TELNET 1.  Commands and characters are sent to operating system on common server computer. 2.  Local operating system send

How free-space is managed using bit vector implementation, How free-space i...

How free-space is managed using bit vector implementation? The free-space list is executed as a bit map or bit vector. Each block is shown by 1 bit. If the block is free, the b

Assembly language programming, write an assembly language program for fibon...

write an assembly language program for fibonacci series?

Variables and quantifiers - first-order logic, Variables and Quantifiers: ...

Variables and Quantifiers: Now we have to diagnose now that if we wanted to say that there is a meal at the Red Lion which costs only 3 pounds, is well sayed. Rather thenif we

What is the system call available to transmit a signal, What is the system ...

What is the system call available to transmit a signal? System call Kill is used to send a signal to a method or a group of processes. Int kill (pad tepid, Int sig); This

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