Transfer rate of a disk drive can be no faster than the bit density (bits/track) times  the rotational speed of the disk. Figure 7.15 gives a data transfer rate of 112GB/sec.  Assume that the average track length of the disk is 5.5 inches. What is the average bit density of the disk?

A blue ray disk has a writing speed of 500 Mbits/s. How long would it take to store a 10 GB raw video file on this blue ray disk? How small would the 10 GB raw video file become if it is compressed with a compression ratio of 5?

01. Consider a disk pack with 16 surfaces, 128 tracks per surface and 256 scctors per track 312 bytes of data are stored in a bit serial manner in a sector. The capacity of the disk pack and the number of bits roquired to specify a particular sector in the disk are respectively

Consider a disk with 2 MB/track, a rotation time of 10 msec, average seek time of 5 msec. On average, how long it takes to read 500 bytes from the disk?

In Feynman's lecture he wondered "why cannot we write the entire 24 volumes of the Encyclopedia Brittanica on the head of a pin". For a modern hard disk drive the area of a single bit of information on the surface of the disk is roughly 10 x 40 nm² in area. In such a hard drive would the area required to store the data for 24 volumes of the Encyclopedia Brittanica be greater or less than the head of a pin? In Feynman's lecture he estimates the 24 million books as big as the Encyclopedia Brittanica has 10¹5 bits of information.

What is the average time to read or write a 512-byte sector for a typical disk rotating at 15,000 RPM? The advertised average seek time is 4 ms, the transfer rate is 100 MB/sec, and the controller overhead is 0.2 ms. Assume that the disk is idle so that there is no waiting time.

A multiplattered hard disk is divided into 1100 sectors and 40,000 cylinders. There are six platter surfaces. Each block holds 512 bytes. The disk is rotating at a rate of 4800 rpm. The disk has an average seek time of 12 msec. a. What is the total capacity of this disk? b. What is the disk transfer rate in bytes per second? c. What are the minimum and maximum latency times for this disk? What is the average latency time for this disk?

Consider a disk with the following characteristics

A disk drive has 1000 cylinders, 8 tracks per cylinder, 32 sectors per track, and 512 bytes per sector. The rotation time is 4ms. The read/write head takes 10ms to move between adjacent cylinders. A data file contains 200KB of data stored consecutively. What is the maximum seek time if the average time needed to read the data is 170ms?

5120 kilobytes is equal ...... in MB (8 МB (4 MB (5 МB (3.2 MB