How Removable Storage Works

By: Jeff Tyson

Magnetic: Zip

The Zip drive comes in several configurations, including SCSI, USB, parallel port and internal ATAPI.
Photo courtesy Iomega Corporation

Over the years, magnetic technology has improved greatly. Because of the immense popularity and low cost of floppy disks, higher-capacity removable storage has not been able to completely replace the floppy drive. But there are a number of alternatives that have become very popular in their own right. One such example is the Zip from Iomega.

A Zip disk
Photo courtesy Iomega Corporation

The main thing that separates a Zip disk from a floppy disk is the magnetic coating used. On a Zip disk, the coating is of a much higher quality. The higher-quality coating means that the read/write head on a Zip disk can be significantly smaller than on a floppy disk (by a factor of 10 or so). The smaller head, in conjunction with a head-positioning mechanism that is similar to the one used in a hard disk, means that a Zip drive can pack thousands of tracks per inch on the disk surface. Zip drives also use a variable number of sectors per track to make the best use of disk space. All of these features combine to create a floppy disk that holds a huge amount of data -- up to 750 MB at the moment.