Phenom Phenom 6, 25 25 gold badges 76 76 silver badges bronze badges. See this set of 6 closely related questions: superuser. And superuser. Add a comment. Active Oldest Votes. Improve this answer. Alex Alex 2, 1 1 gold badge 12 12 silver badges 16 16 bronze badges. That would be the average rotational delay. The maximum would be twice that.
Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. If the format overhead is 64 bytes per sector, how much amount of memory is lost due to formatting?
If the diameter of innermost track is 21 cm, what is the maximum recording density? If the disk is rotating at RPM, what is the data transfer rate? If the disk system has rotational speed of RPM, what is the average access time with a seek time of Step To reach our desired surface, we have to cross 16 surfaces.
Step To reach our desired sector, we have to cross 29 sectors. Now, after crossing 29 sectors on surface of cylinder, we are at sector So, required address of the sector is Option C is correct. Part We have to find the address of the sector Let us check all the options one by one. Magnetic Disk in Computer Architecture- In computer architecture, Magnetic disk is a storage device that is used to write, rewrite and access data. It uses a magnetization process. Architecture- The entire disk is divided into platters.
Each platter consists of concentric circles called as tracks. These tracks are further divided into sectors which are the smallest divisions in the disk. A cylinder is formed by combining the tracks at a given radius of a disk pack. It is used to read from and write to the disk. Head has to reach at a particular track and then wait for the rotation of the platter.
The rotation causes the required sector of the track to come under the head. Each platter has 2 surfaces- top and bottom and both the surfaces are used to store the data. Components that contribute to the service time are- Seek time Rotational latency Data transfer rate Controller overhead Queuing delay 1.
You can calculate transfer time by dividing the size of a byte sector by the transfer rate. To calculate rotational latency , or rotational delay in the context of hard drives, first you need to know an object's angular velocity per unit time. This could be a hard drive velocity of 7, rotations per minute. Convert the time unit to seconds. For 7, rotations per minute, you divide the number by 60 seconds to get rotations per sec. Make sure you measure rotational delay with the same units of time that you want for the disk access time.
You can also obtain average disk access time as the sum of average seek time, average rotational delay, transfer time, queuing overhead and and queuing delay. Queuing time is how long it takes for a disk to become free. First convert the rotational velocity to seconds and the average seek time to seconds to get You can do this by assuming, for random reading and writing, the disk spins halfway on average.
Convert the transfer size 8 kb to mb by multiplying it by 0. Add these numbers in units of seconds as 0.
All this happens through the process of reading from a disk, and you can calculate the response time by adding together seek time, rotational delay, transfer time and overhead.
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