Hard disks work much like floppy disks, just more so.
Instead of thin Mylar coated materials, the hard disk uses an aluminum (or other rigid material) platter covered with a magnetic coating. Also, there is typically more than one disk in any drive. They are stacked like records with the number determining the capacity of the disk.
While hard disks have sectors, because there are multiple surfaces the term track is not used; cylinder is used in its place (one cylinder consists of the stack of tracks under the heads on all disk platter surfaces at any given time).
Because the hard disk spins faster and has increased density over the floppy, environmental controls must be stricter to prevent dust or other damaging agents from getting on the platters. Unlike floppy disks, on a hard disk the heads "fly" a few thousands of an inch over the disk surface instead of riding on the surface. Even so, because of the speed of the head any dust can be disastrous. The hard disk is therefore only seen in a sealed unit. One technology associated with sealed units is termed Winchester technology.
Hard disk capacity ranges from a usual minimum of 40 Megabytes up to several hundred megabytes, gigabytes or more.
Hard disks vary widely in performance. The type of disk, the method data is recorded on the disk, the nature of the interface between the computer and the drive, and several other factors all have a bearing on performance.
Disks with hundreds of megabytes will typically be partitioned by the operating system into logical drives of smaller sizes. Before DOS 4.0 the largest partition was 32MB. DOS 4.0 and later support much larger partitions, allowing you to organize your system any way you wish.
Setting up a hard disk (both partitions and subdirectories) is one of the most important tasks you have when you first get a new microcomputer. Take the time to do it with a plan in mind.
If you have a hard disk, be prepared to spend some time backing up your data. Even with a sealed unit, problems develop, and usually just when they will hurt you the most.
Actually, good backup should be exercised with any disk, hard or floppy
