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[humpty dumpty]

How to calculate following things according to given data of a hard disk ?

number of platters = 3
number of tracks per surface = 200
number of sector per track = 40
sector size = 1024 bytes
hard disk speed = 6000rpm
avg.seek time = 2 ns

Questions,

1. Calculate the total capacity of the hard disk?
2. If a cluster size is 4 kb find the number of clusters.
3. Calculate the rotational delay and access time.
4. Calculate the data transfer rate.


please help.....................
Give me the formulas.

 

[dagayaa]

1. Calculate the total capacity of the hard disk?


sector size = 1024 bytes

number of sector per track = 40 (total track size= 1024*40)

number of tracks per surface = 200 (total surface size= total track size*200)

number of platters = 3 (total platter size=total surface size*3)

if platters are one sided total hard disk space= total platter size
if 2sided total hard disk space = total platter size * 2

 

[dagayaa]

Maximum rotational delay is the time it takes to do a full rotation excluding any spin-up time (as the relevant part of the disk may have just passed the head when the request arrived). Most rotating storage devices rotate at a constant angular rate (constant number of revolutions per second). The maximum rotational delay is simply the reciprocal of the rotational speed (appropriately scaled). In 2001, 7200, 5400 or 4200 revolutions per minute were typical hard disk drive spindle speeds; at 7200 rpm, maximum rotational delay will be 60/7200 s or about 8 ms.

 

[dagayaa]

Access time is the time delay or latency between a request to an electronic system, and the access being completed or the requested data returned.
In a telecommunications system, access time is the delay between the start of an access attempt and successful access. Access time values are measured only on access attempts that result in successful access.
In a computer, it is the time interval between the instant at which an instruction control unit initiates a call for data or a request to store data, and the instant at which delivery of the data is completed or the storage is started.
In disk drives, disk access time is the time required for a computer to process data from the processor and then retrieve the required data from a storage device, such as a hard drive. For hard disk drives, disk access time is determined by a sum of the spin-up time, seek time, rotational delay, and transfer time.
Spin-up time - is the time required to accelerate the disk to operating speed. Most drives are left spinning to improve access time, but drives may be spun down to reduce energy use or noise as for example in laptop computers.
Seek time - is the time for the actuator arm to reach the desired disk track.
Rotational delay - the delay for the rotation of the disk to bring the required disk sector under the read-write mechanism. It greatly depends on rotational speed of a disk, measured in revolutions per minute (RPM).
Transfer time - time during which data is actually read or written to medium, with a certain throughput.
In disk drive art the term Average Access Time usually refers to average seek time.

 

[humpty dumpty]

Maximum rotational delay is the time it takes to do a full rotation excluding any spin-up time (as the relevant part of the disk may have just passed the head when the request arrived). Most rotating storage devices rotate at a constant angular rate (constant number of revolutions per second). The maximum rotational delay is simply the reciprocal of the rotational speed (appropriately scaled). In 2001, 7200, 5400 or 4200 revolutions per minute were typical hard disk drive spindle speeds; at 7200 rpm, maximum rotational delay will be 60/7200 s or about 8 ms.

Thank u bro.............

 

[milroy319]

answr eka hambela neda...