A record in a hard disk’s partition table contains 16 bytes divided into 6 fields. The structure is as follows:
The partition represented above is the same one represented as /dev/hda3 (the 3rd partition) in the following output from the fdisk utility:
Note the following correspondences:
First correspondence – the value of the “active” field can be either 80H or 00H (H indicates the numbers are presented using the base 16 or “hexadecimal” number system). If 00H, the fdisk display shows blank space, if 80H it shows an asterisk.
Second correspondence – the “type” field contains a code number. There is a code number for each possible physical filesystem type in which the partition might be formatted. In the example, it is indicated that 83H is the code assigned to represent the Linux (ext2) filesystem type. There is a large number of other codes and corresponding filetypes.
Third correspondence – the “partition size” field contains the number of sectors represented using 4 2-digit hexadecimal numbers, each of which is the value in one place of a 4-place base-256 number. An example should clarify. The 4-digit base-10 number 5826 appears below, indicating how the value of the number is derived from the values of its 4 digits.
Everybody knows that 5826 means five-thousand eight-hundred twenty-six. But only because they have been taught that 1, 10, 100, and 1000 are part of the calculation even though they are never written. All that is actually written is a total of twenty-one (5 and 8 and 2 and 6). Only the interpretation that people supply, which is purely mental and unwritten, informs what is written with its intended value.
The above p
