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

Operations of a scientific calculator, A program is to be developed to simu...

A program is to be developed to simulate the operations of a scientific calculator. List the facilities to be provided by this calculator. Analyze this using a DFD 0- level and 1-

Explain naming convention globals, Explanation The values of global vari...

Explanation The values of global variables can be used and changed all over the project within all scripts and libraries. However it is highly recommended to remain the number o

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

Describe about relationships and look up fields, Relationships are imported...

Relationships are imported from the source to finish without any hindrance but once they land in the destination they can never be changed or changed and change of extensions canno

Explain application and system software, Fundamentals of IT 1. Explain ...

Fundamentals of IT 1. Explain the Impact of Information Technology on governments and educational organizations. 2. Explain application and system software. 3. Briefly ex

Mips assembly language equivalents , MIPS' native assembly code only has tw...

MIPS' native assembly code only has two branch instructions, beq and bne, and only one comparison instruction, slt. Using just these three instructions (along with the ori instruct

What is telex, Telex is a (A)  Telephone Service between various subsc...

Telex is a (A)  Telephone Service between various subscribers (B)  Tele printer Service between various subscribers (C)  Television Service between various subscri

Differentiate between hardware and software, Differentiate between Hardware...

Differentiate between Hardware and Software Another classification is software vs. hardware. Hardware is the collection of physical components, like chips, wires, PCBs, connect

What do you mean by daisy chain, Q. What do you mean by Daisy chain? Th...

Q. What do you mean by Daisy chain? This scheme provides a hardware poll. With this scheme, an interrupt acknowledge line is chain by different interrupt devices. All I/O inter

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