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

Design a memory buffer of limited size, Extend task 1 so that it now suppor...

Extend task 1 so that it now supports a memory buffer of limited size. Provide the same functionality as task 1 except now make the server work with a limited buffer size. Like

Linux, Explain about unix file system architecture

Explain about unix file system architecture

protects against transcription, The last digit of a credit card number is ...

The last digit of a credit card number is the check digit, which protects against transcription errors like an error in a single digit or switching two digits. The following method

Find the physical address of instruction, Q. Find the Physical address of i...

Q. Find the Physical address of instruction? Value of Instruction Pointer and holding address of instruction = 1234h Value of code segment register (CS) = 448Ah Physical

Explain parsing, What is parsing? The target of parsing is to find out...

What is parsing? The target of parsing is to find out the syntactic validity of a source string. A tree is built for use through subsequent phase of compiler, if the string is

Explain about annotational notations, Explain about Annotational Notations ...

Explain about Annotational Notations These notations may be applied to describe remark and illuminate about any element in the model. They are considered as explanatory of U

Interface constructors, Describe a interface 'Human' with methods as walk' ...

Describe a interface 'Human' with methods as walk' and 'speak'. Describe a class 'User' implementing 'Human'. Describe a work() method in User class.Add a class 'Person' also execu

Summary of tasks, Summary of Tasks Task Summary attempts to show amoun...

Summary of Tasks Task Summary attempts to show amount of duration every task has spent starting from beginning of task until its completion on any processor as displayed in Fi

Show the importance of risc processors, Q. Show the Importance of RISC Proc...

Q. Show the Importance of RISC Processors? Reduced Instruction Set Computers recognize a comparatively limited number of instructions. One benefit of a reduced instruction set

Explain flash devices, Explain Flash devices It is possible to read the...

Explain Flash devices It is possible to read the contents of a one cell, but it is only possible to write an whole block of cells Greater density which leads to superior cap

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