Capacity of Disks

Storage: Disk Capacity

What happens when a disk is formatted?

1.	All data is erased. Don't forget this!!
2.	Surfaces are checked for physical and magnetic defects.
3.	A root directory is created to list where things are on the disk.

The capacity of a magnetic disk depends on several factors.

We always want the highest amount of data stored in the least possible space. (People are so greedy this way!) So the capacities of storage media keep increasing while cost keeps decreasing. It's a lovely situation for the user!

Capacity of a Disk depends on:

1.# of sidesused:
single-sided	double-sided
2.Recording density- how close together the bits can be on a track sector of the innermost track
3.# of tracks on the disk

5¼" floppy

- 360 KB or 1.2 MB

3½" floppy

- 720 KB or 1.44 MB

Hard disk
early ones	= 20 MB
currently (July 2010)	up to 3 TB Internal hard drive where 1 TB = 1 terabyte = 1000 GB

The future???

Advances in technology for the read/write head and for the densities on the disks are bringing larger and larger disk capacities for about the same price. In fact, you cannot find a small capacity drive to buy, even if you wanted one! 2 TB drives are plentiful (July 2010) and for the same price that we used to buy 1 Gig drives (under $200). It's enough to make you cry to think of what we paid over the years and what we could get for those dollars today. Ah, well. That's the way the computer world works!

Дата добавления: 2014-12-23