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

Define nondeterministic tm, Define nondeterministic TM?  Arbitraril...

Define nondeterministic TM?  Arbitrarily chooses move when more than one possibility exists Accepts if there is at least one computation that terminates in an acceptin

What is a privileged instruction, What is a privileged instruction? To ...

What is a privileged instruction? To protect the operating system of a computer from being corrupted by user programs, particular instructions can be executed only whereas the

Secret-key encryption, Secret-key encryption is also called as Private ...

Secret-key encryption is also called as Private encryption.

Super ASCII string checker, In the Byteland country a string "s" is said to...

In the Byteland country a string "s" is said to super ascii string if and only if count of each charecter in the string is equal to its ascci value in the byteland country ascii co

What do you mean by term procedure, What do you mean by term procedure? Dif...

What do you mean by term procedure? Differentiate between far call and near call? PROC: PROC and ENDP directives indicate the start and end of a procedure. These directives for

Name some pure object oriented languages, Some pure object oriented languag...

Some pure object oriented languages are Smalltalk, Eiffel,  Java, Sather.

Can we use flow logic control key words in abap/4, Can we use flow logic co...

Can we use flow logic control key words in ABAP/4 and vice-versa The flow control  of a dynpro having os a few statements that syntactically ressemble ABAP/4  statements .Thou

How to transmits data in the active message buffer, Q. How to Transmits dat...

Q. How to Transmits data in the active message buffer? int pvm_bcast( char *group, int msgtag ) Transmits data in the active message buffer to a group of processes. msgt

Risks by customer perspective in electronic payment system, What are the ri...

What are the risks by customer's perspective in Electronic Payment Systems? Risks within Electronic Payment Systems: Through the customer's perspective are as follows:

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