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

Explain short note about molap?, Classic form of OLAP is called as MOLAP an...

Classic form of OLAP is called as MOLAP and it is often known as OLAP. Simple database structures like time period, product, location, etc are used. Functioning of each and every d

Programming in c, Write a program to find the area under the curve y = f(x)...

Write a program to find the area under the curve y = f(x) between x = a and x = b, integrate y = f(x) between the limits of a and b. The area under a curve between two points can b

How to turn on the session support in php, The session support can be turne...

The session support can be turned on automatically at the site level, or manually in every PHP page script: * Turning on session support automatically at the site level: Set s

Cn, What is the basic requirement for establishing VLANs?

What is the basic requirement for establishing VLANs?

What is the basic approach of page replacement, What is the basic approach ...

What is the basic approach of page replacement?  If no frame is free is available, find one that is not currently being used and free it. A frame can be freed by writing its co

Bernstein conditions for detection of parallelism, Bernstein Conditions for...

Bernstein Conditions for Detection of Parallelism For implementation of instructions or block of instructions in parallel, it should be guaranteed that the instructions are ind

Define point-to-point communication, Q. Define Point-to-point Communication...

Q. Define Point-to-point Communication? The simplest form of message is a point to point communication. A message is sent from the transmitting processor to a receiving process

Chemistry, what are the applications of photochemistry?

what are the applications of photochemistry?

What is immediate addressing, What is Immediate addressing The  data  i...

What is Immediate addressing The  data  itself,  beside  the address,  is  given  as  the  operand or operands  of  the instruction.

Explain the semantics of each field of ethernet frame, Give the format of E...

Give the format of Ethernet frame and explain the semantics of each field. An Ethernet frame starts with headers which have three fields. The 64-bit preamble, which precedes th

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