10 Oct
2009
10 Oct
'09
7:24 p.m.
Hi! Why does sector numbering start with physical Sector 1 on floppy and
hard disks?
Cylinders and Heads begin at 0 but sectors start at 1. What happened to
Sector 0?
I am referring to physical address not LBA.
I am just wondering. Thanks and have a nice day!
Andrew Lynch
10 Oct
10 Oct
8:14 p.m.
On Sat, 10 Oct 2009, Andrew Lynch wrote:
Hi! Why does sector numbering start with physical
Sector 1 on floppy and
hard disks?
Cylinders and Heads begin at 0 but sectors start at 1. What happened to
Sector 0?
I am referring to physical address not LBA.
I am just wondering. Thanks and have a nice day!
Track numbering goes bask to the designers of the disk controller.
Sector numbering, on the other hand, is a creation of the systems
programmers who design that particular disk format.
SOME sector numberings start with 0.
SOME sector numberings start with 1.
SOME sector numberings start with 17
SOME sector numberings start with 129
The programmers who design the individual disk format do not have much
control over track numbering, but can do anything that they want with
sector numbers.
--
Grumpy Ol' Fred cisin at xenosoft.com
8:18 p.m.
On 10 Oct 2009 at 22:24, Andrew Lynch wrote:
Hi! Why does sector numbering start with physical
Sector 1 on floppy
and hard disks?
Cylinders and Heads begin at 0 but sectors start at 1. What happened
to Sector 0?
Convention, mostly. At least for soft-sectored media, the sector
(and side and cylinder, really) can be anything the person who writes
the low-level formatting software wants it to be.
There are systems out there that use sector 0 as the first sector (HP
125, for example or several Kaypro formats). By the same token,
there are systems that use 65, 128 or 192 as the first sector. I
know of at least one system that used the sector ID to differentiate
between single- and double-sided formats.
There is at least one PC AT ST412 interface hard disk controller out
there that uses a "hidden" 256-byte sector 0 to record the drive
parameters.
Cylinder, head and sector numbers need not even be consecutive,
although that does make things easier when a controller capable of
multi-sector transfers is used.
--Chuck
10:09 p.m.
Hi! Why does
sector numbering start with physical Sector 1 on floppy and
hard disks?
Cylinders and Heads begin at 0 but sectors start at 1. What happened to
Sector 0?
Amiga floppies have sectors numbered 0-10.
5551
days inactive
5551
days old
4 comments
5 participants
participants (5)
-
cclist＠sydex.com -
cisin＠xenosoft.com -
keithvz＠verizon.net -
lynchaj＠yahoo.com -
spectre＠floodgap.com