Physical sector location

If you have a given sector, say 5000th sector (logical), how can you
get the physical location in: platters, tracks and sectors?

Nuno Magalhaes wrote:

If you have a given sector, say 5000th sector (logical), how can you
get the physical location in: platters, tracks and sectors?

Have a look he

http://www.geocities.com/thestarman3...iveOffsets.htm

for a good discussion.

Virg Wall
--
A foolish consistency is the
hobgoblin of little minds,........
Ralph Waldo Emerson
(Microsoft programmer's manual.)

On 5 Nov 2003 05:49:57 -0800, (Nuno Magalhaes)
wrote:

If you have a given sector, say 5000th sector (logical), how can you
get the physical location in: platters, tracks and sectors?

There is no absolute guaranteed way. Two main causes.
1. Most drives use variable bit rate recording. That means there are more
bits per track on the outer tracks of the drive than there are on the inner
tracks. What that bit rate is depends on the drive and manufacturer.

2. Bad sectors are automatically remapped and replaced by spare sectors
included on the drive for just such an occurance. The block will normally
be close to where the defective block was, but there is no guarentee of
where it will be or come from. Fresh from the factory drives will normally
have a few remapped sectors, and as the drive ages, error recovery will
remap sectors that go bad. Where a sector on the disk is today might not be
the same place tommorow.

JT

JT wrote:

On 5 Nov 2003 05:49:57 -0800, (Nuno Magalhaes)
wrote:

If you have a given sector, say 5000th sector (logical), how can you
get the physical location in: platters, tracks and sectors?

There is no absolute guaranteed way. Two main causes.
1. Most drives use variable bit rate recording. That means there are more
bits per track on the outer tracks of the drive than there are on the inner
tracks. What that bit rate is depends on the drive and manufacturer.

2. Bad sectors are automatically remapped and replaced by spare sectors
included on the drive for just such an occurance. The block will normally
be close to where the defective block was, but there is no guarentee of
where it will be or come from. Fresh from the factory drives will normally
have a few remapped sectors, and as the drive ages, error recovery will
remap sectors that go bad. Where a sector on the disk is today might not be
the same place tommorow.

JT

Normal use of the term "physical" does not refer to the actual position on
the disk platters but rather the CHS, (cylinder,head,sector), that the drive
electronics has mapped them to. The convention of 63 sectors per track, is,
as you point out, no longer valid.

The reference I gave is a good way to get from CHS to the sector's "offset",
or logical sector number, which is shown on most disk editors.

Virg Wall
--
A foolish consistency is the
hobgoblin of little minds,........
Ralph Waldo Emerson
(Microsoft programmer's manual.)