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

Assessing heuristic searches-artificial intelligence, Assessing Heuristic S...

Assessing Heuristic Searches Given a specific problem you want to create an agent to solve, there can be more than one way of specifying it as a search problem, more than one o

Explain the linux from scratch system, Problem 1 (a) Explain the RAID ...

Problem 1 (a) Explain the RAID system and explain all possible configurations. (b) Summarize design goals, features and specifications of the Linux ext2 file system. (c

Explain about data segment, DATA SEGMENT  NUM1            DB      15h;...

DATA SEGMENT  NUM1            DB      15h;     First number   NUM2            DB      20h;     Second number  RESULT DB?  ; Put sum here  CARRY DB? ; Put any carry he

What is debate - architecture, What is Debate Debate took place in the ...

What is Debate Debate took place in the 1980s and first half of the 1990s. It was resolved as RISC the winner since it allows more efficient pipelining, results in simpler hard

Show the conditional jump in program with example, Q. Show the conditional ...

Q. Show the conditional jump in program? CMP    AX, BX                      ; compare instruction: sets flags JNE     FIX                             ; if not equal do addi

Write a verilog code for synchronous and asynchronous reset, Write a Verilo...

Write a Verilog code for synchronous and asynchronous reset? Synchronous  reset, synchronous means clock dependent so reset must not be present in sensitivity disk eg: alway

Explain grade of service with reference to telephone traffic, With referenc...

With reference to telephone traffic, explain the terms GOS. GOS: in loss systems, the traffic carried through the network is usually lower than the actual traffic offered to

How and what data is gathered- simulation, How and what data is gathered- S...

How and what data is gathered- Simulation To make this as realistic as possible, data is required to be gathered over a long period of time. This can be done by sensors near/i

To which one erlang is equal, One Erlang is equal to (A)  3600 CCS ...

One Erlang is equal to (A)  3600 CCS (B)  36 CCS (C) 60 CCS (D)  24 CCS Ans: One Erlang is equivalent to 3600 CCS.

Mutability and accessibility of primary memory, Mutability and Accessibilit...

Mutability and Accessibility of primary memory: Mutability: Read/write storage or mutable storage  It provides permit ion for the information to be overwritten at

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