What are the types of format?

Answer 1

Assuming you mean formatting as in preparing a disk for use, there are two main types of formatting. The first is a low-level or physical format, and the other is an upper level or logical format. A low-level format creates the tracks and sectors. A high-level format may clear the tracks and sectors, but often just verifies them, and it will add a file-system to the disk.

When you format a diskette, both types of formatting takes place. The drive lays down the tracks and sectors. While doing that, it verifies the newly created sectors, and then at the end of that, it creates the boot record and the two FAT tables.

Formatting a hard drive is much different from formatting a diskette. It is a three step process. In the old days, you had to first low-level format the hard drive. That required using either a program stored on the controller (and a weird Debug command sequence to access it) or a third-party utility. That is where the sectors are created, and you often had to type in a defect map so the drive would know where its bad spots were. Hard drives are not perfect, and if there are bad spots, you'd want to skip them and lay sectors past them. The second part of the step was to create a partition table. The third step was to run the Format program in DOS or Windows to do the higher level formatting.

However, modern hard drives come with a low-level format and refuse to let you low-level format them. It is physically impossible for them to correctly low-level format themselves, since by their design, factory equipment would be required. If you try to low-level format them, they will intercept the commands, pretend to low-level format, but only wipe the logical contents without touching the sector and track boundaries. So that means you can only partition them and do a high-level format.