How to access the disk data, Computer Engineering

Assignment Help:

Q. How to Access the Disk Data?

Disks operate is semi-random mode of operation and generally referenced block wise. The data access time on a disk comprises two major components:

  • Seek time: Time to position head on a particular track. On a fixed head disks it's time taken by electronic circuit to select needed head whereas in movable head disks it's time needed to move head to a specific track.
  • Latency time: This is time needed by a sector to reach below read/write head. On an average it's half of time taken for a rotation by disk.

In addition to seek and latency time the time taken to transfer a (read/write) block of words can be considered however normally it is too small in comparison to seek time and latency and in general disk access time is concerned to be sum of seek time and latency time. Because access time of disks is large so it is advisable to read a sizeable part of data in a single go and so disks are referenced block wise. As a matter of fact you will find that in most of computer system input/output involving disk is given a very high priority. Fundamental reason for such priority is latency time which is needed once the block which is to be read passes below read-write head. It may take time of order of milliseconds to do it again, in turn delaying Input /Output and lowering performance of system.


Related Discussions:- How to access the disk data

How can arithmetic processor be associated to the CPU, Q. How can this arit...

Q. How can this arithmetic processor be associated to the CPU?  Two mechanisms are used for connecting arithmetic processor to CPU.   If an arithmetic processor is treated a

Explain the uses of keyboards, Explain the uses of Keyboards An alphanu...

Explain the uses of Keyboards An alphanumeric keyboard for a graphics system is used primarily as a device for entering text strings. Keyboards can also be provided with featur

Object-oriented program and cell controlled class architectu, Object-Orient...

Object-Oriented Program And Cell Controlled Class Architecture To the variety of scenarios, generic cell control architecture can be applied. An object oriented programming lan

What is paging unit, Paging Unit Paging mechanism functions with 4K -...

Paging Unit Paging mechanism functions with 4K - byte memory pages or with a new extension available to Pentium with 4M byte-memory pages. In the Pentium, with the new 4M-byt

Internal structure of agents - artificial intelligence, Internal Structure ...

Internal Structure of Agents: We have looked at agents in terms of their external influences and behaviors: they put in from the surroundings and perform rational actions to a

C program , minimum number of shelves

minimum number of shelves

How can common bus system be constructed, How can common bus system be cons...

How can common bus system be constructed A common bus system could be constructed using multiplexers. These multiplexers select source register whose binary information is then

TITLE: Signals for digital communications, DETERMINE ANALYTICALY IF THE SIG...

DETERMINE ANALYTICALY IF THE SIGNAL IS PERIODIC OR NOT - X[n] = 4Cos(Pi n)

Personal computing environment, Reply and discuss the role of the SAS 70 re...

Reply and discuss the role of the SAS 70 report in reviewing internal controls. Provide publicly available examples of SAS 70 reports and explain. Problem Discuss the

Concept of multithreading, Concept of Multithreading: These troubles incre...

Concept of Multithreading: These troubles increase in the design of large-scale multiprocessors such as MPP as discussed above. Thus, a solution for optimizing this latency should

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