rdbtool¶
the universal Amiga disk partition tool
Introduction¶
The rdbtool
is a tool from the amitools tool set that allows to inspect or
create hard disk partitions readable by the classic Amiga family of computers.
The RDB or Rigid Disk Block is a format to describe the first blocks of a
hard disk that store information of partitions and file systems used in the
partitions.
If you want to work with files stored in the DOS file system of a partition then have a look at the xdftool of amitools.
Usage¶
Disk Image Files¶
rdbtool is a command line utility that is always called with an hard disk image file path name as the first argument and with one or more commands working on this image:
> rdbtool <image.rdb|image.rdisk> <command> [option]
You can issue multiple commands on a single image by concatenating them with a plus character:
> rdbtool <image.rdb> <command1> [options1] + <command2> [options2] ...
For example:
> rdbtool myimg.rdb create size=10Mi + init + fill
Most options in rdbtool are given as key=value
pairs. Here the option
size
is given with value 10Mi
for a 10 MiB sized disk image.
Real Block Device¶
On Unix/Linux/macOS you can also use a block device of a real hard disk or a
CF/SD flash card to directly work on a real device. The file names for the
block device differ on the different platforms but typical names are
/dev/rdisk1
or /dev/sda
.
Always make sure to select the block device of the whole drive (e.g.
/dev/hdc
) and not the device of some already existing paritioning (e.g.
/dev/hdc1
).
Warning
Also make sure (really, really sure!) to select the correct block device of
the hard disk you want to alter with rdbtool
. Otherwise you might
destroy your actual system disk!!! Most OSes need a priviliged user to
perform these operations so you need to run rdbtool
as root
or with
sudo
in this case.
Commands¶
This section describes the commands available for rdbtool. You can always
issue a help
command to see all commands:
> rdbtool test.img help
Open/Create an Image¶
In rdbtool there are two ways to access an image: open or create it. The
open
operation assumes that the disk image file already exists or is used
for existing devices available through block device names.
create
- Create a new disk image¶
create [ size=<size> | chs=<cyl>,<heads>,<secs> | from=<img> ] [ bs=<n> ]
The create
operation is used to create a new image file. The create
command needs a size parameter:
> rdbtool test.img create size=10Mi
You can either specify the total size in bytes (or here with unis M=mega Mi=Ki-Units) and let rdbtool choose a suitable disk geometry automatically or you can give the geometry with:
> rdbtool test.img create chs=10,1,32
Here 10 cylinders, 1 head and 32 sectors are defined.
Another way to specify the size of the new image is to give the file name of an existing image or real device. This is useful to create a new image of compatible size:
> rbdtool test.img create from=other.img
You can only use the create
command if the given image file does not exist
yet. If it already exists then an error message is generated. However, you can
force the creation of the image file by giving the -f
switch for force:
> rdbtool -f test.img create chs=10,1,32
By default a disk layout with a block size of 512 bytes is created. For larger
disks you may want to increase the block size to 1024, 2048, or 4096. Use the
bs`
option to select the block size:
> rdbtool create size=32Gi bs=4096
Note
Amigas only support RDBs with a 512 byte block size!
open
- Open existing image for processing¶
open [ chs=<cyl>,<heads>,<secs> | c=<cyl> h=<heads> s=<secs> ] [ bs=<n> ]
The open operation usually does not need any paramters:
> rdbtool test.img open + info
You can even omit the open
command before other commands in this case:
> rdbtool test.img info
This will implicitly open the image first.
If no option is given then the disk geometry is automatically determined from the image size. If this does not work for an image you can also specify the geometry of the image in the open command:
> rdbtool test.img open chs=10,1,32
You can also only hint the geometry by giving some geometry paramters and let rdbtool guess the others:
> rdbtool test.img open c=10 h=2 s=32
By default the block size of the disk is assumed to be 512. If an RDB is
already stored on the disk then rdbtool
automatically retrieves the block
size from there. You can force a block size by giving the bs
option with
the open
command. This is useful if you want to overwrite an existing RDB
with a different block size on a disk:
> rdbtool /dev/disk1 open bs=4096 + init
Note
Amigas only support RDBs with a 512 byte block size!
resize
- Change size of existing image¶
resize [ chs=<cyl>,<heads>,<secs> | c=<cyl> h=<heads> s=<secs> | from=<img> ] [ bs=<n> ]
Similar to the create
command you can specify the new size of an image.
It will be either shrunk or grown.
Note
The RDB that may be already on the disk is not touched or adjusted!
Use the adjust
command to adjust the RDB as well.
Inspect the Partition Layout¶
info
- Show information of the RDB data structures¶
info [partition]
This command gives an overview of the partitions and file systems stored in the RDB blocks. It will return something like:
PhysicalDisk: 0 7817 7880544 3.8Gi heads=16 sectors=63
LogicalDisk: 2 7817 7878528 3.8Gi rdb_blks=[0:2015,60(60)] cyl_blks=1008
Partition: #0 'CDH0' 2 103 102816 50Mi 1.31% DOS3 bootable pri=0
Partition: #1 'DH0' 104 205 102816 50Mi 1.31% DOS3
Partition: #2 'DH1' 206 2035 1844640 900Mi 23.41% DOS3
Partition: #3 'DH2' 2036 3763 1741824 850Mi 22.11% DOS3
Partition: #4 'DH3' 3764 3909 147168 71Mi 1.87% DOS3
Partition: #5 'CDH1' 3910 3971 62496 30Mi 0.79% DOS3
Partition: #6 'DH4' 3972 4124 154224 75Mi 1.96% DOS3
Partition: #7 'DH5' 4125 5953 1843632 900Mi 23.40% DOS3
Partition: #8 'DH6' 5954 7817 1878912 917Mi 23.85% DOS3
FileSystem #0 DOS1 version=40.1 size=24588
If a partition name (.e.g DH0
) or index (e.g. 3
) is given then only
the information for a single partition is displayed:
> rdbtool test.hdf info DH0
Partition: #1 'DH0' 104 205 102816 50Mi 1.31% DOS3
list
- List information of the RDB data structures¶
list [partition]
This command is very similar to the info
command as it gives a
complete overview of the RDB data structures. But the output is more
dense and details are omitted. E.g. the DOS environment is not shown:
BlockDevice: 0 30516 976544 476Mi heads=1 sectors=32 block_size=512
PhysicalDisk: 0 30516 976544 476Mi heads=1 sectors=32 block_size=512
LogicalDisk: 1 30516 976512 476Mi rdb_blks=[0:31,#32] used=[hi=3,#4] cyl_blks=32
Partition: #0 'root' 1 6400 204800 100Mi 20.97% NBR7/0x4e425207
Partition: #1 'swap' 6401 12800 204800 100Mi 20.97% NBS1/0x4e425301 auto boot(0)
Partition: #2 'usr' 12801 30516 566912 276Mi 58.05% NBU7/0x4e425507
json
- Print the RDB data structures in JSON Format¶
json [out.json]
This command is very similar to the info
command but dumps all
information in JSON format.
If out.json
is given then the JSON output is written to this file.
Otherwise the JSON is dumped to stdout.
show
- Show internal block representation of the RDB data structures¶
show
This command is a low-level tool that shows the blocks available in the RDB data structure with their corresponding values. Use this to debug or analyze issues with complex RDBs.
Create a new RDB¶
init
- Create a new and empty RDB structure¶
init [ rdb_cyls=<cyls> ]
This command creates a new and initially empty RDB structure.
Call this command first to start building a new RDB structure on a disk or disk image:
> rdbtool test.img create size=10Mi + init
The default RDB occupies all the sectors of the first cylinder. If you have
chosen a geometry with small cylinders then a single cylinder might not be
sufficient to hold the RDB data structures. In this case use the rdb_cyls
option to set the number of cylinders to reserve for RDB:
> rdbtool test.img create size=10Mi + init rdb_cyls=2
adjust
- Adjust range of existing RDB structure¶
adjust ( auto [ force ] | [ lo=<cyl> ] [ hi=<cyl> ] [ phys ] )
This command changes the range on the disk that the current RDB covers. It is very handy if you copy a pre-existing image file to a real medium (e.g. compact flash card) with a larger size.
You can either use the auto
mode that automatically increases the RDB
range to cover the full image or medium. If the cylinder number gets too
large then you need to add the force
option to allow the change.
> rdbtool /dev/disk4 adjust auto
In manual mode you have to specify the new range of the RDB by giving either
the lo
and/or hi
cylinder. If you add the phys
option then
not only the logical range of the RDB will be changed but also its
physical extend.
> rdbtool test.img adjust hi=1000 phys
The adjust
command will abort with an error if the existing partitions
do not fit into the new range.
remap
- Change geometry of existing RDB structure¶
remap [ s=<sectors> ] [ h=<heads> ]
This command allows to change the interal geometry of the disk image. The geometry consists of cylinders, heads, and sectors. Typically, the number of heads and sectors is chosen in such a way that the number of cylinders spanning the image does not grow too large.
If you want to adjust
an RDB to a larger device size then the cylinder
ranges might get too large. In this case use the remap
command first
to increase the sectors and/or heads to keep the cylinders in a reasonable
range.
> rdbtool image.rdb remap s=32 h=8
Note that the remap
operation is only allowed if the physical and logical
disk layout can be converted to the new values without any resizing.
Additionally, all partition ranges must be mappable as well.
add
- Add a new partition¶
add <size> [ name=<name> ] [ dostype|fs=<dostag> ]
[ bootable[=true|false] ] [ pri=<priority> ]
[ automount=true|false ] [ bs=<n> ]
This command creates a new partition.
You have to give the size of the partition in one of the following ways:
Give start and end cylinder:
start=<cyl> end=<cyl>
Give start cylinder and size:
start=<cyl> size=<cyl|percent|bytes>
Only give size:
size=<cyl|percent|bytes>
For the size you can specify a number of cylinders, a percent value, or a byte size (The percent value gives the ratio of the total logical disk size):
> rdbtool test.img add start=2 end=5 ; give start and end cylinder
> rdbtool test.img add start=4 size=10 ; give start and number of cylinders
> rdbtool test.img add size=10MiB ; give size in bytes
> rdbtool test.img add size=50% ; use half the disk size
If no name
option is given then the defaul name DH
is used appended
with the current partition number starting with 0: DH0, DH1
. You can alter
the base name by giving the -p
switch (for drive prefix):
> rdbtool -p CH test.img init + add size=10% ; create partition CH0
The dostype
or fs
switch can be used to select the file system you
will use to format the partition. The default is DOS3
, i.e. Fast Filing
System with International Support. You can give the dostype with DOS<n>
or
as a hex number 0x44556677
or for standard DOS file systems with ofs
,
ffs
and append dc
or dircache
or intl
flags:
dostype=DOS0 ; OFS
dostype=ofs+dc ; OFS + dircache
dostype=ffs+intl ; FFS + international mode
dostype=0x44556677 ; give hex of dostype
You can make a partition bootable by setting the bootable
flag.
Additionally you can select the boot priority with pri=<n>
:
> rdbtool test.img add size=10% bootable pri=10
The bs
option allows you to specify the block size of the file system.
By default rdbtool
uses the block size of the RDB parition itself, e.g.
512. The file system block size must be a multiple of the parition block
size, e.g. 1024, 2048, 4096, or 8192.
addimg
- Add a new partition from an image file¶
addimg <file> [ start=<cyl> ]
[ name=<name> ] [ dostype|fs=<dostag> ]
[ bootable[=true|false] ] [ pri=<priority> ]
[ automount=true|false ] [ bs=<n> ]
This command creates a new partition from the contents of a given partition
image file. The size of the partition is automatically derived from the file
size. The start of the partition is either given with the start
option
or selected automatically from the next free range in the partition table.
Note that the image size must be a multiple of the cylinder size. Otherwise the partition can’t be added.
The dostype
is automatically derived from the first four bytes of the
image file. The file system block size can’t be detected automatically and
must be given with the bs
option if a non-standard (512 bytes) size is
used.
See the add
command for an explanation of the other options.
change
- Modify parameters of an existing partition¶
change <id> [ name=<name> ] [ dostype|fs=<dostag> ]
[ bootable[=true|false] ] [ pri=<priority> ]
[ automount=true|false ] [ bs=<n> ]
The <id>
is the number of the paritition as given in the info
command.
You can also use the device name to select a partition:
> rdbtool test.img change 0 name=CH0 bootable=true
For options see the add
command.
free
- Show free cylinder range in partition layout¶
free
This command returns one or more cylinder ranges that are currently not occupied by partitions. You can use this command to find out the range for a new partition.
If the current partition layout aready occupies the whole disk then this command will return nothing.
fill
- Fill the remaining space in the partition layout¶
fill [ name=<name> ] [ dostype|fs=<dostag> ]
[ bootable[=true|false] ] [ pri=<priority> ]
[ automount=true|false ] [ bs=<n> ]
This command takes the free space in a partition layout and creates a new partition that fills this space.
This command supports the same options as used in the add
command above.
If multiple holes are in the current partition layout then this command creates a new partition for each existing hole.
With this command you can easily finish paritioning without the need of calculating the size of the final partition:
# create 2 partitions with 50% size each
> rdbtool test.img init + add size=50% + fill
> rdbtool test.img init + add size=10% + add size=20% + fill
For options see the add
command.
delete
- Delete an existing partition¶
delete <id>
This command removes an existing partition and frees all associated resources.
The <id>
is the number of the paritition as given in the info
command.
You can also use the device name to select a parition:
> rdbtool mydisk.rdb delete 0
> rdbtool mydisk.rdb delete dh1
map
- Show the allocation map of the RDB blocks¶
map
This command lets you look under the hood of the RDB. It will print all blocks associated with the RDB and shows their current contents. A two char code is used for each block:
-- block is empty and not used for RDB
RD the main rigid disk block
P? partition <n>
F? file system <n>
Example:
> rdbtool mydisk.rdb map
Import/Export Partitions¶
export
- Export Data of a Partition into a File¶
export <partition> <file_name>
Store the raw byte contents of a partition into the given file.
As a result a file system image will be written. You can use the result
as a RDB-less image in xdftool
.
import
- Import Data from a File into a Partition¶
import <partition> <file_name> [pad]
Read the raw partition data from a given file into an existing partition. You typically use a RDB-less file system image as input.
The size of the input file has to match the partition size.
If you give the pad
option the input file may be smaller and overwrites
only the beginning of the partition area.
Working with File System Drivers¶
The RDB data structure allows to store file system drivers for classic AmigaOS, so the Kickstart can load the driver before mounting a parition in the RDB.
File systems are LoadSeg()able Amiga Hunk binaries directly embedded in the RDB blocks.
Use the info
command to see if any file systems are already stored in the
RDB. In the output you can see that the file systems are numbered in rdbtool
starting with 0.
fsget
- Retrieve the file system driver from a RDB structure¶
fsget <id> <filename>
This command extracts the file system numbered <id>
and stores the
LoadSeg()able Amiga binary on your local system into a new file with the given
<filename>
:
# create a new file "ffs" with the first driver
> rdbtool mydisk.rdb fsget 0 ffs
fsadd
- Add a new file system driver¶
fsadd <filename> [version=<x.y>]
Add the LoadSeg()able file system driver stored in file <filename>
to the
current RDB.
Every file system driver needs a version information given as <x>.<y>
,
e.g. 40.63
. When a file is loaded the version is automatically extracted
from a VER:
tag inside the binary. If this tag cannot be found you can
specify the version with the version
option:
> rdbtool mydisk.rdb fsadd ffs version=60.32
fsflags
- Change flags of file system¶
fsflags <id> [ clear | key=value ... ]
With this command you can alter the device node flags of a file system.
The file system <id>
is the number of the file system as listed with the
info
command.
The following keys are supported:
type
task
lock
handler
stack_size
priority
startup
seg_list_blk
global_vec
The clear
option will remove all flags first. All other commands add the
corresponding flag:
> rdbtool mydisk.rdb fsflags 0 clear stack_size=8192
Have a look at the output of the info
command to see the flags set for a
file system.
fsdelete
- Remove a file system¶
fsdelete <id>
The file system with the given number is removed. All associated blocks of the file system are free’d in the RDB structure.