Assume that we are using a hard disk with the following characteristics: Capacit
ID: 3851976 • Letter: A
Question
Assume that we are using a hard disk with the following characteristics:
Capacity 30 GB
Average seek time 6 msec
Spindle speed 15,000 rpm
Bytes per sector 512
Sectors per cluster 8
Sectors per track 400.
Assume that we have a file of 20, 000 records. Each record has 64 bytes. Answer the following questions:
1. How much is the average rotational delay?
2. How many records can be stored in one sector?
3. How many clusters are needed for the file?
4. How much is the time for reading one track, including the seek time, the average rotational delay, and the transfer time?
5. Assuming contiguous storage, namely the records are stored in clusters from the same track as long as possible, how much is the total time for reading the whole file?
6. Assuming the minimal transfer unit is one cluster, how much is the time for reading one cluster, including the seek time, the average rotational delay, and the transfer time?
7. Assuming random storage of the records and every record is stored in a different cluster, reading a cluster will include the seek time, the average rotational delay, and the transfer time for that cluster, how much is the total time for reading the whole file?
Explanation / Answer
1)
15000rotation in 60seconds
1 rotaion in 60/15000 seconds
half rotation in 60/30000 seconds = 1/500sec
Therefore avg rotational delay = 1/500sec = 2msec
2)
1 sector = 512bytes
1 record = 64bytes
therefore 1 sector = 8 (512/64)records
3)
8 records in 1 sector
20000 records in 2500 sectors
each cluster have 8 sectors
so to accomodate 2500 sectors we need 312.5 clusters. Since clusters cannot be fractional. we need 313clusters
4)
Seek time: 6msec
Avg rotational delay: 2msec
transfer time : 4msec (time required for 1 complete rotation)
Therefore total is 12msec
Chegg does not allow answering more than 4 subquestion. Am really sorry that for such reason, I cannot answer more questions
If you need any assistance on any of the question, feel free to comment below. I shall be glad to help you