home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Vectronix 2
/
VECTRONIX2.iso
/
FILES_01
/
SMON_1B3.LZH
/
HARDDISK.INF
< prev
next >
Wrap
Text File
|
1991-02-28
|
3KB
|
71 lines
066000003000000132000000006000000
1 0
2 0
F0110000001
9[..........................................................]0110
Ç THE HARD DISK PARTITION (OR ROOT) SECTOR
This is some information shamelessly stolen from various sources,
and which may be of some interest to hard disk users. None of it
is guaranteed to be accurate or complete. If you REALLY want to
get into your hard disk, look elsewhere.
This only deals with standard Atari partition hard disks.
LAYOUT
The hard disk itself is layed out as follows:
ROOT SECTOR
BAD SECTOR LIST
PARTITION 1
ANY FURTHER PARTITIONS
Each partition has it's own BOOT sector (sector zero).
The root sector could be regarded as the DRIVE's boot sector.
The first few hundred bytes are taken up with boot code. This
checks the keyboard to see if the Alternate key is pressed, if
so, it disables auto booting. If not, it finds out if there is a
self booting partition, and establishes contact. I think at this
stage the hard disk driver is loaded and tied into the system.
So we start with the information at:
(B) $1B8 Number of heads (2 ARE better than 1, but usually
there are more than that)
(B) $1BE Landing track number
(B) $1BF Seek rate (in milli secs)
(B) $1C0 Interleave (normally 1)
(B) $1C1 Sectors per track
(68) $1C2 Total number of sectors for the ENTIRE disk (lots)
(B) $1C6 p0-fig 1 byte indicates partition exists (bit 0)
and whether bootable (bit 7)
$1C7 p0-id 3 bytes identifier (GEM if Gemdos partition,
BGM for >16Meg partition, XGM for extended,
but can be other things for other purposes.
$1CA p0-st Start of partition (in sectors) from the
very beginning of the hard disk.
$1CE p0-siz Size of the partition in sectors (512 bytes)
$1D2 to $1DD More of the same for partition 2
$1DE to $1E9 And again for partition 3
$1EA to $1F5 And 4
(68) $1F6 BSL_ST Offset to the beginning the bad sector list
(68) $1FA bsl_cnt Size of the bad sector list (number sectors)
$1FE Reserved
(B) means byte, (68) means a 68000 format (high/low) long word.
The p-fig byte: If bit 7 is set, the partition is bootable. Dos
will simply boot the first partition it comes to with this bit
set. The Atari DOS will always give info for 4 partitions, if it
doesn't exist bit 0 is simply turned off.
So, a quick look in the root sector at location $1FA will show
you how many bad sectors your hard disk has.
Looking at the p- blocks gives info on the partitions.
So, what do you do with this information? Who cares, it's here.
Ç Will Visser
