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 isdn address structure and its working, Draw the ISDN address struc...

Draw the ISDN address structure and explain how the addressing works? Address Structure: The ISDN address structure is demonstrated in figure. ISDN number part has a maximum

Compare the memory devices ram and rom, Compare the memory devices RAM and ...

Compare the memory devices RAM and ROM. Ans. Comparison of Semi-conductor Memories RAM ands ROM The advantages of ROM are: 1. This is cheaper than RAM. 2. This is non-volatil

State the example of begin end, State the Example of begin end module s...

State the Example of begin end module sequential(); reg a; initial begin $monitor ("‰g a = ‰b", $time, a); #10 a = 0; #11 a = 1; #12 a = 0; #13 a = 1; #

What is cyclomatic complexity, What is cyclomatic complexity? Cyclomati...

What is cyclomatic complexity? Cyclomatic complexity is a computer science metric (measurement) developed by Thomas McCabe used to generally calculate the complexity of a progr

Define sr flip flop - sr latch with nor gate, Define SR Flip Flop - SR latc...

Define SR Flip Flop - SR latch with NOR Gate? The SR Flip flop neither is a circuit with two cross-coupled NOR gates or two cross-coupled NAND gates. SR

Depth-first search is different from breadth-first search, Depth-first sear...

Depth-first search is different from Breadth-first search in the following ways: A depth search traversal method goes to the deepest level of the tree first and then works up w

Thematic analysis - flash design, Thematic Analysis & Interpretation: ...

Thematic Analysis & Interpretation: The next steps in analysis are to move beyond what is literally there in the image (formal visual elements) and examine the meaning they re

What are threads, What are threads? A thread, sometimes termed as a lig...

What are threads? A thread, sometimes termed as a lightweight process (LWP), is a fundamental unit of CPU utilization; this comprises a thread ID a register set and a stack and

What is block started by symbol, What is BSS(Block Started by Symbol)? ...

What is BSS(Block Started by Symbol)? A data showing at the machine level, that has initial values when a program begins and tells about how much space the kernel assigns for t

Determine about the three-state gate, Determine about the three-state gate ...

Determine about the three-state gate A three-state gate is a digital circuit which shows three states. Two of them are equivalent to logic 1 and 0.  The third one is a high im

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