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*** D2M (Electronic form of a CMD FD2000 1.56 Mb floppy disk)
*** DNP (Electronic form of a CMD hard Disk Native Partition)
*** Document revision: 1.3
*** Last updated: Nov 27, 2005
*** Compiler/Editor: Peter Schepers
*** Contributors/sources: Torsten Hinrichs (sample files),
Malte Munde (sample files),
Wolfgang Moser,
Roberto Muscedere,
Bo Zimmerman (sample DNP files)
Much of the information contained in this document has been gathered by
dissecting FD2000 floppy images (in D2M format) and DNP hard disk images,
comparing them, and arriving at some well-educated conclusions. Comparisons
to some other disk types (D81, D64) have helped immeasurably. Therefore,
some of the information presented here might not be accurate or complete.
CMD devices are incredibly compatible. The FD2000 is is backwards
compatible to the Commodore 1581 floppy, contains the JiffyDos fastloader,
and even supports the GEOS OS. Inserting a native-formatted FD2000 floppy
keeps the drive in its native mode support, but inserting a 1581-formatted
disk will put the drive into "1581 compatible" mode. It even supports
"emulated" partitions of 1541, 1571 and 1581 disks on native-formatted
disks.
The D2M image is considered a "container" image as it contains other
image types like D64, D71, D81 and native partitions as well. The container
nature makes supporting D2M more difficult than other image types.
The extension DNP was arrived at after discussions between Bo Zimmerman
and this document author. It stands for CM(D) (N)ative (P)artition.
Unfortunately we could not assign it CMD as that would conflict with the
Windows OS CMD interpeter batch files.
There are several different ways to view the layout of FD2000 floppies.
At the controller level, the disk has 81 tracks (physically numbered 0 to
80), 10 sectors-per-track, 2 disk sides with 1024 bytes per sector. In
Commodore logical terms, it has 81 tracks (1 to 81 logical), 80
sectors-per-track with 256 bytes per sector, totalling 6480 sectors total.
This makes the disk 1.56Mb in size. The last track (81, image offset
$190000) is reserved and should not be used for data storage. This makes
the file size 1658880 without error bytes attached, or 1665360 bytes with
error bytes attached.
Seeing as the disk is 6480 sectors large, we need 6480 error bytes
attached to the end of the image for an extended image type. About the only
use for the error bytes is when emulating 1541 or 1571 drive types, and a
bad sector for copy protection is needed. The job codes these error bytes
represent only really apply the 1541 and 1571 drives.
While it may seem logical to interact with the disk with 81 tracks, it
fails in practice and the reason is simple. Internally, all track & sector
links in the native and emulated partitions (not system) refer to the disk
as a 256 sector/track so you must work with the disk this way. This means
the FD2000 image actually has 26 tracks, 25 for the image and a partial
track 26 (80 sectors only) for the system partition. Coding a proper
support structure for one CMD device image like D2M means that it would
also be easy to make it work for any other image like DNP (except for the
lack of a system partition).
So, what does it mean when track 2 sector 233 ($02/$E9) is accessed? To
answer this, we need to convert the track and sector numbers into
HEXADECIMAL, because calculating the resulting offset location become very
simple. Taking the example above (track 2 sector 233), convert them to HEX
numbers...
track 2 -> $02
sector 233 -> $E9
subtract 1 from the track value (because all track references are from 1,
not zero), attach the sector value to the end, and then attach a $00 to the
end...
($track-1):$sector:$00 or $01E900.
This is the offset value into the existing partition to access track 1
sector 233.
Additionally, each partition internally always starts from track 1. How
is this possible? Well, the system partition table specifies what offset a
partition starts at (in system blocks), and once inside the partition, all
track references now start at 1. This means *you* must keep track of the
offset where each partition exists once you are inside. As a bonus, this
also means that moving a partition from one disk to another should be very
simple because all the track/sector references and chains are "relative"
and do not have to be adjusted.
CMD devices like the FD2000 floppy and CMD hard disks contain a "system
partition" (described later) which stores up to 31 user-created partitions
(also called segments), with the types defined below. One of the partitions
will be set as the default so that when the disk is inserted in the floppy,
the default partition will be entered automatically. The first entry is
always set as the "system" entry.
There are several different types of partitions, which are...
Type Description Size
---- --------------------------- -----------------------------------
00 No partition 0
01 Native partition variable (min 256 512-byte blocks)
02 Emulated 1541 drive (D64) 342 512-byte blocks (684 sectors)
03 Emulated 1571 drive (D71) 684 512-byte blocks (1368 sectors)
04 Emulated 1581 drive (D81) 1600 512-byte blocks (3200 sectors)
255 System partition (track 81)
The emulated drive partitions are a direct sector copy of the disk type.
This means the track/sector references are just as a normal disk would be,
even though the FD2000 doesn't normally do things this way. If you were to
sector-by-sector copy the data out from this emulated partition to a new
file, you would have a D64 (or D71/D81) image file in all respects.
There are two things to watch out for if you intend to copy the data from
emulated partitions out to a real disk. Both the 1541 and the 1571 contain
extra "filler" sectors on the end. The 1541 contains one, and the 1571
contains two. A partial explanation for this behaviour is that the FD2000
system partition works with 512-byte blocks, meaning all partitions must be
even numbers (in 256-byte blocks). Therefore the 1541 size is incremented
to the next logical size (684) to make is an even value. The 1571 is simply
a doubling of the 1541 size, even though this means it now contains *two*
extra filler sectors (which are now completely unnecessary).
For more information on the layout of 1541 (D64), 1571 (D71), 1581 (D81),
GEOS, REL or any of the specific file types on the disks, see the
appropriate documentation which should be included with this one.
It is the native partition type which is the most powerful to use because
it is capable of so much, being a greatly improved disk format over the
D64.
The System Partition (D2M/D4M images only)
------------------------------------------
Every CMD storage device contains a system partition, but not all the
images do. The D2M and D4M images do contain the system partition, but the
DNP image does not as it is only a copy of the native partition portion
from a CMD hard disk. Therefore this section only refers to the floppy
(D2M) images.
The system partition exists at track 26 (offset $190000), and is broken
up into several different areas. With only 80 sectors on this track
(instead of the normal 256), there is potentially a lot of information.
However, only sector 5 and 8-11 seem to be used.
The system partition contains no BAM map. In order to add new partitions,
a pseudo-map would need to be built based on the existing partition entries
starting positions and sizes to know where there is empty space on the disk
for more partitions.
Sector 5 (offset $190500) holds the DevBlock, the "device information
block". Most of the information here is unknown, but it likely contains
information about the device itself, and possibly which partition is set as
the default. This block should be duplicated as-is when generating a D2M
image file as it does not appear to change across any of the images that
have been seen.
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
190500: 00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190510: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190520: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190530: FF FF FF FF FF FF FF FF 00 00 FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190540: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190550: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190560: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190570: 00 0C FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190580: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190590: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1905A0: FF FF FF FF FF FF FF FF 00 80 FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1905B0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1905C0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1905D0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1905E0: 00 00 01 01 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1905F0: 43 4D 44 20 46 44 20 53 45 52 49 45 53 20 20 20 CMD<4D>FD<46>SERIES<45><53><EFBFBD>
Byte:$00-EF: unknown
F0-FF: Disk identifier string (in ASCII, padded with $20)
Sectors 8-11 (offset $190800-190BFF) hold the system partition directory
containing information for as many as 31 separate partitions. The example
below shows the 4 allowed partition types along with the required "SYSTEM"
entry. All partition entries are 32 bytes long but the first two bytes are
not used for the entry.
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
190800: 01 01 FF 00 00 53 59 53 54 45 4D A0 A0 A0 A0 A0 <20><><EFBFBD><EFBFBD><EFBFBD>SYSTEM<45><4D><EFBFBD><EFBFBD><EFBFBD>
190810: A0 A0 A0 A0 A0 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190820: 00 00 04 00 00 31 35 38 31 2F 50 41 52 54 49 54 <20><><EFBFBD><EFBFBD><EFBFBD>1581/PARTIT
190830: 49 4F 4E A0 A0 00 00 00 00 00 00 00 00 00 06 40 ION<4F><4E><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>@
190840: 00 00 03 00 00 31 35 37 31 50 41 52 54 49 54 49 <20><><EFBFBD><EFBFBD><EFBFBD>1571PARTITI
190850: 4F 4E A0 A0 A0 00 06 40 00 00 00 00 00 00 02 AC ON<4F><4E><EFBFBD><EFBFBD><EFBFBD>@<40><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190860: 00 00 02 00 00 31 35 34 31 50 41 52 54 49 54 49 <20><><EFBFBD><EFBFBD><EFBFBD>1541PARTITI
190870: 4F 4E A0 A0 A0 00 08 EC 00 00 00 00 00 00 01 56 ON<4F><4E><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>V
190880: 00 00 01 00 00 4E 41 54 49 56 2D 50 41 52 54 49 <20><><EFBFBD><EFBFBD><EFBFBD>NATIV-PARTI
190890: 54 49 4F 4E A0 00 0A 42 00 00 00 00 00 00 02 00 TION<4F><4E><EFBFBD>B<EFBFBD><42><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1908A0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1908B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1908C0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1908D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1908E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1908F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190900: 01 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190910: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190920: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190930: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190940: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190950: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190960: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190970: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190990: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1909A0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1909B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1909C0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1909D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1909E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
1909F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A00: 01 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190A90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190AA0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190AB0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190AC0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190AD0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190AE0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190AF0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B00: 00 FF 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190B90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190BA0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190BB0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190BC0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190BD0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190BE0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
190BF0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Notice that the chain links are 1/1, 1/2, 1/3, and ends with a $00/$FF.
What is happening here is the drive is using 26/5 as the start of the
system partition, which now make 26/5 appear as logical 1/0. This is an
example of partitions starting at track 1 internally even though they
physically reside elsewhere. Therefore, even though the system partition
starts at 26/5, this is actually logical track/sector 1/0 and you need to
keep track of the starting offset of this partition so that accesses still
start as 26/5.
The first entry is the root name. This entry must exist first...
190800: 01 01 FF 00 00 53 59 53 54 45 4D A0 A0 A0 A0 A0 <20><><EFBFBD><EFBFBD><EFBFBD>SYSTEM<45><4D><EFBFBD><EFBFBD><EFBFBD>
190810: A0 A0 A0 A0 A0 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Byte:$00-01: track/sector reference to next partition block
02: Partition type (255=system partition)
03-04: unknown, set to $00
05-14: root name (16 characters, padded with $A0)
15-1F: set to $00
The next entry is the first partition...
190820: 00 00 04 00 00 31 35 38 31 2F 50 41 52 54 49 54 <20><><EFBFBD><EFBFBD><EFBFBD>1581/PARTIT
190830: 49 4F 4E A0 A0 00 00 00 00 00 00 00 00 00 06 40 ION<4F><4E><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>@
Byte:$00-01: not used
02: Partition type
00 - No partition
01 - Native FD2000 partition
02 - Emulated 1541 disk (D64)
03 - Emulated 1571 disk (D71)
04 - Emulated 1581 disk (D81)
03-04: unknown, set to $00
05-14: Partition name (16 bytes, padded with $A0)
15: unknown, set to $00
16-17: Starting offset to partition, in hi/lo format (note that
these blocks are 512-byte blocks)
18-1D: unknown, set to $00
1E-1F: Partition size, in hi/lo format (note that these blocks
are again 512-bytes in size)
*Note: the "partition size" and "starting offset" values are some other
examples of the oddities of the FD2000 layout. They are counted in 512-byte
sectors, not the standard 256-byte sectors of other Commodore disks. What
this means is you must double the value to get the actual size in 256-byte
sectors.
In the case of emulated drive partitions, the size is already known, as
it is a sector-for-sector duplicate of the emulated disk. An emulated 1541
disk will have one extra sector at the end of the image because it is an
odd size (683) and the size must always be even, being multiples of 512
bytes.
The third partition example from above ("1571PARTITION") shows a block
offset of $0640 and a block size of $02AC. Since these are in 512-byte
blocks, we need to double them to get the real 256-byte sector values
($0C80 and $0558). This means that this partition starts at file offset
$0C8000, and is $0558 (or 1368) sectors large. The file offset number must
be remembered as all references within the partition must be added to the
above offset value to get the real offset into the D2M image.
Native Partitions (D2M and DNP images)
--------------------------------------
All partitions inside of a D2M image must start on a 512 byte boundary,
and end on one as well. The minimum size for a native partition is 256
system blocks (or 512 sectors in 256-byte sectors). Part of the reason for
the minimum size is the number of blocks that the BAM and other areas
allocate (35 blocks) even before you get a chance to do anything.
Keep in mind that a DNP image does not contain a system partition but is
only the native partition from a CMD hard disk. It is therefore not
considered a "container" image type. The maximum track size for DNP is 255.
This puts the upper limit on this image at 16,711,680 bytes. To determine
the track size of a DNP image, simply divide the image size by 65536. If
there is any remainder, this means there is a partial track stored at the
top so increment the track size by one.
The first sector ($01/$00) of a native partition is reserved for the C128
boot block. CMD designed the drive this way, allocating the first sector
automatically, so the partition HEX dump will start at the next sector,
$01/$01.
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
0000: 01 24 48 00 53 55 42 44 49 52 31 38 A0 A0 A0 A0 <20>$H<>SUBDIR18<31><38><EFBFBD><EFBFBD>
0010: A0 A0 A0 A0 A0 A0 54 49 A0 31 48 A0 A0 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>TI<54>1H<31><48><EFBFBD><EFBFBD><EFBFBD>
0020: 01 23 01 01 01 22 02 00 00 00 00 00 00 00 00 00 <20>#<23><><EFBFBD>"<22><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
00A0: 00 00 00 00 00 00 00 00 00 00 00 01 25 47 45 4F <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>%GEO
00B0: 53 20 66 6F 72 6D 61 74 20 56 31 2E 31 00 00 00 S<>format<61>V1.1<EFBFBD><EFBFBD><EFBFBD>
00C0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
00D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
00E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
00F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Byte:$00-01: Track/sector reference to root directory block of this
partition ($01/$24).
02: Disk format type ("H")
03: unknown, set to $00
04-15: Disk name (16 characters, padded with $A0)
16-17: Disk ID's ("TI")
18: Set to $A0
19: DOS Version ("1")
1A: Disk format type ("H")
1B-1C: Set to $A0
1D-1F: unknown, set to $00
20-21: Track/Sector pointer to present directory header block
22-23: Track/Sector pointer to parent directory header block
(set to $00/$00 when at the top of the directory)
24-25: Track/Sector pointer to dir entry in previous directory
(set to $00/$00 when at the top of the directory)
26: Index pointer to dir entry in parent directory (set to
$00 if at the top of the directory)
27-AA: unknown, set to $00
AB-AC: GEOS border sector
AD-BC: GEOS format string (GEOS format Vx.x)
BD-FF: Unknown, set to 00
The references at $20 through $26 take a little more explanation. The
track/sector link at $20-$21 points to the header of the present directory.
This way when you are in the directory listing, you know where the header
block is, and it can be accessed to find out how to go back one level, or
change the header name, etc.
The t/s link at $22-23 points back to the immediately previous directory
(parent entry), allowing you to go backwards up the directory tree one step
at a time. Note that there is no value for a jump back to the top level
directory. This value is known only when you enter the partition.
The t/s link at $24-25 points to the sector where the entry for the
present directory name exists (one level up), and the value at $26 is the
real index into this sector pointing directly at the name. This entry is
important because if you add extra entries to a directory, forcing the
addition of another sector, the parent entry must be updated with a new
block count. The reference at $24-26 tells you exactly where the parent
entry is.
If the directory header contains the GEOS format signature at offset $AD,
then the directory is ready for GEOS use. See the GEOS.TXT document for
more explanation of GEOS features. It is not known if children
subdirectories under a parent which is GEOS formatted must also be GEOS
format. However, each directory, regardless of where it is, uses it's own
GEOS border sector if it is formatted for GEOS.
The BAM map for a native partition starts at track 1 sector 2 and extends
up to sector 33. Why is it 32 sectors long? A native partition supports up
to 255 tracks (at 256 sectors per track). Doing the math, this makes the
BAM table 8160 bytes long, or approximately 32 sectors. A native partition
inside of a D2M image can only go up to track 25 of 255 due to the physical
size limits of the D2M, so most of the table is unused and filled with
$FF's. However, a DNP image can use up to 255 tracks, so the entire BAM
will be used.
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
000200: 00 00 48 B7 4A 4F C0 00 19 00 00 00 00 00 00 00 <20><>H<EFBFBD>JO<4A><4F><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000210: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000220: 00 00 00 00 0F FF FF FF 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000230: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000240: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000250: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000260: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000270: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000290: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0002A0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0002B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0002C0: 00 00 00 00 00 00 00 00 00 00 00 00 40 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>@<40><><EFBFBD>
0002D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0002E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0002F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
..
000500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000510: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000520: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000530: 00 00 00 00 00 00 00 07 FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000540: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000550: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Byte:$00-01: unknown, set to $00
02: Disk format type ("H")
03 1's complement of format type ("H" EOR $FF)
04-05: Disk ID's ("JO")
06: unknown (seems to be the same value from the 1581 image,
I/O byte)
bit 7 set - Verify on
bit 7 clear - Verify off
bit 6 set - Check header CRC
bit 6 clear - Don't check header CRC
07: unknown, set to $00
08: Last available track # in partition ($19=#25)
09-1F: unknown, set to $00
20-FF: BAM for tracks 1-7
BAM block Covers tracks
------------ ------------------------------
1 (#01/#02) 01-07 (starts at offset $20)
2 (#01/#03) 08-15 (starts at offset $00)
3 (#01/#04) 16-23 ''
4 (#01/#05) 24-31 ''
... ...
30 (#01/#31) 232-239 ''
31 (#01/#32) 240-247 ''
32 (#01/#33) 248-255 ''
Track Offset Range
----- --------------
01 $000220-00023F
02 $000240-00025F
03 $000260-00027F
04 $000280-00029F
..
253 $0021A0-0021BF
254 $0021C0-0021DF
255 $0021E0-0021FF
The BAM bit breakdown is not very complicated. Each track allocation
takes exactly 32 bytes. Looking at the above entry, we can extract the
entry for track 1 (all 256 sectors), which starts at track 1, sector 2,
offset $20 ($000220)...
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
000220: 00 00 00 00 0F FF FF FF 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
000230: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Each byte represents 8 sectors. The first series of six bytes are broken
down as follows...
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
76543210 76543210 76543210 76543210 76543210 76543210
-------- -------- -------- -------- -------- --------
00000000 00000000 00000000 00000000 00001111 11111111
<20> <20> <20> <20> <20> <20> <20> <20> <20> <20> <20> <20>
<20> <20> <20> <20> <20> <20> <20> <20> <20> <20> <20> <20>
<20> <20> <20> <20> <20> <20> <20> <20> <20> <20> <20> <20>
<20> <20> <20> <20> <20> <20> <20> <20> <20> <20> <20> <20>
<20> Sec 7 <20> Sec 15 <20> Sec 23 <20> Sec 31 <20> Sec 39 <20> Sec 47
Sec 0 Sec 8 Sec 16 Sec 24 Sec 32 Sec 40
Byte #0 covers sector 0-7, #1 covers 8-15 and so on. A '1' bit means the
sector is free, and a '0' bit means the sector is allocated (used). For an
empty partition, sectors 0-34 are always allocated. Note that even though
sector 0 is not used (completely empty), it is still allocated.
Looking back to the first sector of the partition block, it had the next
t/s link set as $01/$22 (offset $002200), so here is the dump of that
sector, which is the first directory block. This block is very similar in
layout to a normal disk (D64, etc) containing GEOS files.
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
002200: 01 23 86 01 40 45 43 48 4F 20 48 41 57 4B A0 A0 <20>#<23><>@ECHO<48>HAWK<57><4B>
002210: A0 A0 A0 A0 A0 00 00 00 00 60 01 02 15 13 02 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>`<60><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
002220: 00 00 86 02 32 50 4C 55 52 41 4C A0 A0 A0 A0 A0 <20><><EFBFBD><EFBFBD>2PLURAL<41><4C><EFBFBD><EFBFBD><EFBFBD>
002230: A0 A0 A0 A0 A0 00 00 00 00 60 01 02 15 19 02 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>`<60><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
002240: 00 00 86 03 04 52 45 41 43 54 4F 52 A0 A0 A0 A0 <20><><EFBFBD><EFBFBD><EFBFBD>REACTOR<4F><52><EFBFBD><EFBFBD>
002250: A0 A0 A0 A0 A0 00 00 00 00 60 01 02 15 20 04 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>`<60><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
002260: 00 00 86 04 D8 54 48 45 20 54 52 41 49 4E A0 A0 <20><><EFBFBD><EFBFBD><EFBFBD>THE<48>TRAIN<49><4E>
002270: A0 A0 A0 A0 A0 00 00 00 00 60 01 0A 10 23 03 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>`<60><><EFBFBD>#<23><>
002280: 00 00 86 06 62 49 4E 46 49 4C 54 52 41 54 4F 52 <20><><EFBFBD><EFBFBD>bINFILTRATOR
002290: A0 A0 A0 A0 A0 00 00 00 00 60 01 0A 10 2B 06 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>`<60><><EFBFBD>+<2B><>
0022A0: 00 00 86 08 FE 53 54 4F 4E 45 20 41 47 45 A0 A0 <20><><EFBFBD><EFBFBD><EFBFBD>STONE<4E>AGE<47><45>
0022B0: A0 A0 A0 A0 A0 00 00 00 00 60 01 0A 12 04 05 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>`<60><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0022C0: 00 00 86 0A D6 4E 49 43 4B 20 46 41 4C 44 4F 20 <20><><EFBFBD><EFBFBD><EFBFBD>NICK<43>FALDO<44>
0022D0: 47 4F 4C 46 A0 00 00 00 00 60 01 0A 12 09 02 00 GOLF<4C><46><EFBFBD><EFBFBD><EFBFBD>`<60><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0022E0: 00 00 86 0A D8 52 2D 54 59 50 45 A0 A0 A0 A0 A0 <20><><EFBFBD><EFBFBD><EFBFBD>R-TYPE<50><45><EFBFBD><EFBFBD><EFBFBD>
0022F0: A0 A0 A0 A0 A0 00 00 00 00 60 01 0A 12 0D 05 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>`<60><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Byte:$00-01: T/S link to next directory block (set to $00/$FF if it's
the last sector of the directory)
02: Entry type. Typical values for this location are:
$00 - Scratched (deleted file entry)
80 - DEL file
81 - SEQ file
82 - PRG file
83 - USR file
84 - REL file
85 - 1581 partition (only in emulated 1581 disks)
86 - Native FD2000 subdirectory
Bit:0-3: The actual filetype
000 (0) - DEL
001 (1) - SEQ
010 (2) - PRG
011 (3) - USR
100 (4) - REL
101 (5) - 1581 partition
110 (6) - FD2000 subdirectory
Values 7-15 are illegal
4: Not used
5: Used only during SAVE-@ replacement (?)
6: Locked flag (if set produces ">" locked files)
7: Closed flag (Not set produces "*", or "splat"
files)
03-04: Track/sector location of first sector of entry
05-14: 16 character filename (in PETASCII, padded with $A0)
15-16: Starting track/sector of REL super-side-sector info (If
GEOS file, t/s link to info block)
17: REL record length (if GEOS file, GEOS file structure
descriptor, $00=sequential, $01=VLIR file)
18: unknown, set to $00 (If GEOS file, GEOS file type
descriptor)
19-1D: File time/date stamp (seconds are not stored). This is
the same timestamp that GEOS uses.
19: Year (add 1900 for real year)
1A: Month (1=JAN, 2=FEB etc)
1B: Day (#1-#31)
1C: Hour (24 hour time, #00-#23)
1D: Minute (#00-#59)
1E-1F: Size in sectors, low/high byte order ($1E + $1F * 256).
The filesize in bytes is <= #sectors * 254
20-3F: Second dir entry. From now on the first two bytes of
each entry in the sector should be $00/$00, as they are
unused.
40-5F: Third dir entry
60-7F: Fourth dir entry
80-9F: Fifth dir entry
A0-BF: Sixth dir entry
C0-DF: Seventh dir entry
E0-FF: Eighth dir entry
The above "size" at $1E-1F can either be the sector count of the file
entry (file size), or the directory size if it's a directory. If it is a
directory, it counts both the header and directory blocks but not any files
or subsequent subdirectory blocks. This value will increment if any extra
directory blocks that need to be allocated to store more files/directories.
Directory space is allocated dynamically, so the size will vary depending
on how many entries are in the subdirectory, and how many blocks the whole
directory takes. It might help to think of the native partition directory
structure and capabilities as you would on a MSDOS machine. They are both
dynamic, and appear to support as many subdirectories as disk space allows.
There does not appear to be any limit on how many directory levels deep one
can go. The "xxx blocks free" that would be seen after a directory listing
would apply across the entire partition, as does the BAM for the partition.
Also note the timestamp on bytes $19-1D. The FD2000 drive has a built-in
real-time clock, allowing for an accurate time/date stamp on file and
directory creation. It is the same stamp that GEOS has used for years. For
more info on GEOS files, read the GEOS.TXT document.
Looking back at the first directory block, it had the entry "ECHO HAWK"
set as a subdirectory, with it's T/S location as $01/$40 (offset $004000),
and it's block size as 2. Here is the dump of the first block of that
subdirectory.
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
----------------------------------------------- ----------------
004000: 01 41 48 00 45 43 48 4F 20 48 41 57 4B A0 A0 A0 <20>AH<41>ECHO<48>HAWK<57><4B><EFBFBD>
004010: A0 A0 A0 A0 A0 A0 4A 4F A0 31 48 A0 A0 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>JO<4A>1H<31><48><EFBFBD><EFBFBD><EFBFBD>
004020: 01 40 01 01 01 22 02 00 00 00 00 00 00 00 00 00 <20>@<40><><EFBFBD>"<22><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
004030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
004040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
004050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
004060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
004070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
004080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
004090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0040A0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0040B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0040C0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0040D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0040E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
0040F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Byte:$00-01: Track/sector link to next directory block ($01/$41, or
$004100)
02: Disk format type ("H")
03: unknown, set to $00
04-15: Directory name (16 characters, padded with $A0)
16-17: Disk ID's ("JO")
18: Set to $A0
19: DOS version ("1")
1A: Disk format type ("H")
1B-1C: Set to $A0
1D-1F: unknown, set to $00
20-21: Track/Sector pointer to present directory header block
($01/$40, points to itself)
22-23: Track/Sector pointer to parent directory header block
($01/$01, points to previous directory)
24-25: Track/Sector pointer to dir entry in previous directory
($01/$22)
26: Index pointer to dir entry in parent directory ($02)
27-FF: unknown, set to $00
Each directory is preceeded by this "header" block, including the root
(from above). This block is necessary because it is the only location which
can hold the "directory" name, and all the track/sector pointers into
various levels of the directory structure.
From here, we go to the next block of the directory, holding the actual
file listing, possibly with more subdirectories. This is block #2 (out of
2) of the entry total. The layout and description is the same as the
previous example of the first directory block.
Creating A D2M Image
--------------------
Follow these steps to create a D2M image. These instructions do not
describe how to create a partition entry or subdirectories. For this info,
you will need to read the above information very carefully.
1. Create a new file, and write out 6480 256-byte blocks of zero's.
2. If you need error bytes, write out another 6480 bytes of $01's. This
is the job code for "no error".
3. Copy the DevBlock exactly, as shown previously (located in an existing
image at track 26, sector 5, or offset $190500).
4. Create the system partition as described above (track 26, sector
8-11).
5. Make sure the "SYSTEM" entry exists as the first entry in the system
partition.
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