Physical Heads vs "Logical" Heads

Hi,

I have a HDD with 16 physical heads according to the label
on the HDD. When this HDD was installed, partitioned, formatted,
etc., a "Block Information" program shows this HDD has "128"
heads, which I assume to be "logical" heads. What "logical"
heads would physical head "0" (zero based) represent?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.

"Brad" wrote in message
...
Hi,

I have a HDD with 16 physical heads according to the label

Ever since ZBR came on the scene the sectors per track, heads, cyl are
basically funny numbers which have no relationshp to reality.

on the HDD. When this HDD was installed, partitioned, formatted,
etc., a "Block Information" program shows

What is ithat? Program name ? Source ?
this HDD has "128"
heads, which I assume to be "logical" heads. What "logical"
heads would physical head "0" (zero based) represent?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.

For operating systems like Window 98, part of the process of communication
between the operating system and the disk involves encoding the number of
cylinders (tracks), heads, and sectors per track (CHS) into a fixed-size
value. This provides for 1024 cylinders, 255 heads, and 63 sectors per
track. If this process was enforced, then the maximum size of hard disk
that could be accessed would be one in which any one of these values was at
the maximum - for instance, a disk could not have more than 1024 cylinders.
In order to allow the OS to access very large hard disks the CHS values
became more-or-less arbitrary, and were translated into actual values in the
disk drive internal logic. If you look at your disk drive you should notice
that the difference in number of heads is matched by a corresponding but
opposite difference in number of cylinders to keep the track number below
1024 (although the calculation might be complicated by a similar adjustment
in the sectors per track). In fact, the sectors per track is even more
artificial, because the disk is probably organised internally to have a
different number of sectors per track for different tracks, again in order
to squeeze the maximum capacity out of the disk. So the CHS values have
simply become a number that is agreed between the OS and the disk drive, and
which bears no relation to the actual physical organisation of the drive
other than it reflects the effective total capacity of the drive.

Presumably, physical head zero would always be logical head zero, but as
soon as the logical head number gets above the actual number of heads then
the way that the two values correspond becomes a mystery known only to the
manufacturer.
--
Jeff Richards
MS MVP (DTS)
"Brad" wrote in message
...
Hi,

I have a HDD with 16 physical heads according to the label
on the HDD. When this HDD was installed, partitioned, formatted,
etc., a "Block Information" program shows this HDD has "128"
heads, which I assume to be "logical" heads. What "logical"
heads would physical head "0" (zero based) represent?

Hi Steve,

The "block information" (HDD is a "block" device) program is a feature
built into "Sector Access" which you can download from

www.simtel.net/pub/pd/52692.html

When you select view a physical sector/s, the "block information"
is shown.
Brad


On Fri, 25 Jun 2004 18:49:51 -0000, "Steve Baron - KB3MM"
wrote:


"Brad" wrote in message
...
Hi,

I have a HDD with 16 physical heads according to the label

Ever since ZBR came on the scene the sectors per track, heads, cyl are
basically funny numbers which have no relationshp to reality.

on the HDD. When this HDD was installed, partitioned, formatted,
etc., a "Block Information" program shows

What is ithat? Program name ? Source ?
this HDD has "128"
heads, which I assume to be "logical" heads. What "logical"
heads would physical head "0" (zero based) represent?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.

I see the [[program download but not sure what else you might be
hoghlighting.

"Brad" wrote in message
...
Hi Steve,

The "block information" (HDD is a "block" device) program is a
feature
built into "Sector Access" which you can download from

www.simtel.net/pub/pd/52692.html

When you select view a physical sector/s, the "block information"
is shown.
Brad


On Fri, 25 Jun 2004 18:49:51 -0000, "Steve Baron - KB3MM"
wrote:


"Brad" wrote in message
...
Hi,

I have a HDD with 16 physical heads according to the label

Ever since ZBR came on the scene the sectors per track, heads, cyl are
basically funny numbers which have no relationshp to reality.

on the HDD. When this HDD was installed, partitioned, formatted,
etc., a "Block Information" program shows

What is ithat? Program name ? Source ?
this HDD has "128"
heads, which I assume to be "logical" heads. What "logical"
heads would physical head "0" (zero based) represent?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.