ector holds 512 bytes of knowledge. By dividing the entire range of sectors by eight, we have a tendency to see that there ar thirty five,843,686 sectors per surface. Dividing once more by 49855, we have a tendency to see that there ar roughly 719 sectors per track. it's fascinating that the particular range is 718.96 sectors per track. Why isn’t this price an entire number? In alternative words, however will we've a divisional range of sectors per track? There ar variety of potentialities and that we needn't hesitate it. However, one risk is that the amount of sectors per track isn't uniform across the disk surface as a result of the world spacing changes as we have a tendency to move from the middle of the disk to the skin. in an exceedingly read-only memory or videodisc drive this can be corrected by dynamical the motility speed of the drive because the optical maser moves in and out. But, since the disc rotates at a set rate, dynamical the recording density as we have a tendency to move from inner to outer tracks makes the foremost sense. Anyway, back to our calculation. If every track holds 719 sectors and every sector is 512 bytes, then every track holds 368,128 bytes of knowledge. Since there ar eight tracks per cylinder, every cylinder holds two,945,024 bytes. Now, here’s wherever the large numbers are available in. Since we've 49855 cylin-ders, our total capability is 146,824,171,520 bytes, or 146.8 Gbytes. Before we have a tendency to leave the topic of disk drives, let’s take into account an added issue. Considering the drive specifications, above, we have a tendency to see that access times ar measured in units of milliseconds (msec), or thousandths of a second. Thus, if your information sectors ar opened up over the disk, then accessing every block of 512 bytes will simply take seconds of your time. examination this to the time needed to access information hold on in main memory, it's straightforward to envision why the drive is ten,000 times slower than main memory