Low level format

Low level format
After setting parameter of hard disk in CMOS Setting, why the hard disk is still unusable? That’s
about Cylinder, Header and Sector. When hard disk is firstly made in the factory, it usually is
“blank”. Only after partitioning tracks and sectors, we can save data on hard disk (Now, before
leaving the factory, many disks have been low-level formatted. So you may need not do the
operation, but it is not unnecessary.)
Main functions of low level format
Low level format can also be called physical format, whose functions are to detect the magnetic
media, to partition tracks, to partition sectors for each track, and to arrange the order of
partitions in track according to the interleave the customer choose. Its main functions are as
following:
Test the hard disk media
Partition tracks for hard disk
Arrange sectors for each track according to the specified interleave
Set the sector ID to each track and finish setting sectors
Test the hard disk surface, mark “bad” to the damaged track and sector
Write a certain ASC to each sector of hard disk
Hard disk is an important storage resource in computer system. Do not low-level format the hard
disk unless it is the only thing possible. For hard disk being used, you need back up important data
before low level format; even if back up is unnecessary, it may take much time to partition,
high-level format, and install system and application programs. Usually, low level format can be
used in the following cases:
1 When you have bought a new hard disk or hard disk adapter, you’d better low level format it
again, which is for the better matching of hard disk and hard disk adapter.
2 “Bad” sectors, which result from long-time operation, often cause “sector not found” error in
DOS. This is because of the loss of sector ID. Sector ID is used to distinguish the sectors. It is
marked onto disk as the magnetization map, which however, may dribble away for long-time
storage or use. Low level format is the only way for computer users to refresh sector ID in
disk. This assignment cannot be done by high level format.
3 Appropriate set of interleave can fasten data transfer. In most conditions, low level format is
the only way to change the interleave.
4 When there are always inexplicable problems, you can take low level format into
consideration.
Ways to low-level format
There are many ways to low-level format. In early time, it can be completed in CMOS or by some
special disk tools, or by writing some short programs in Debug. Nowadays, people usually use
special tools provided free by hard disk manufacturers.