Chapter 6. Disk Partitions and Filesystems

Cylinders, sectors, tracks, and heads are the building blocks of spindle storage. Understanding the millions of bytes confined to a space that is half an inch thick, two inches wide, and three inches in length is critical to data recovery.

Consider the smallest form of storage that every person, at one time or another, has held in the palm of his or her hand. Most of us over the age of 25 recollect ravaging our desk, digging for the all-important, "critical-to-life" 1.44 MB floppy. This critical piece of plastic never fails to be found under the heaviest object on the desk. It is amazing that any data survives on the floppy after removing the seven-pound differential equations bible that was covering it. However, today's storage needs require much larger devices and more advanced methods to protect and recover the data they hold.

The following key topics are discussed in this chapter:

• SCSI and IDE data storage concepts

• The Ext2/3 filesystem

• The concepts of Cylinder, Head, and Sector (CHS)

• Global unique identification

• Partition tables

Throughout the chapter, we present scenarios that deliver real-world examples of the topic discussed in each section.