In computing, a rigid disk block (RDB) is the block on a
hard disk where the
Amiga series of computers store the disk's partition and filesystem information. The
IBM's PC equivalent of the Amiga's RDB is the
master boot record (MBR).
Unlike its PC equivalent, the RDB doesn't directly contain metadata for each partition. Instead it points to a
linked list of partition blocks, which contain the actual partition data. The partition data includes the start, length, filesystem, boot priority, buffer memory type and "flavor", though the latter was never used. Because there is no limitation in partition block count, there is no need to distinguish primary and extended types and all partitions are equal in stature and architecture.
Additionally, it may point to additional filesystem drivers, allowing the Amiga to boot from filesystems not directly supported by the ROM, such as
PFS or
SFS.
The data in the rigid disk block must start with the
ASCII
ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...
bytes "RDSK". Furthermore, its position is not restricted to the very first block of a volume, instead it could be located anywhere within its first 16 blocks. Thus it could safely coexist with a master boot record, which is forced to be found at block 0.
Nearly all Amiga hard disk controllers support the RDB standard, enabling the user to exchange disks between controllers.
See also
*
Master Boot Record (MBR)
*
Extended Boot Record
An extended boot record (EBR), or extended partition boot record (EPBR), is a descriptor for a logical partition under the common DOS disk drive partitioning system. In that system, when one (and only one) partition record entry in the master boot ...
(EBR)
*
GUID Partition Table
The GUID Partition Table (GPT) is a standard for the layout of partition tables of a physical computer storage device, such as a hard disk drive or solid-state drive, using universally unique identifiers, which are also known as globally unique i ...
(GPT)
*
Boot Engineering Extension Record
The host protected area (HPA) is an area of a hard drive or solid-state drive that is not normally visible to an operating system. It was first introduced in the ATA-4 standard CXV (T13) in 2001.
How it works
The IDE controller has registers ...
(BEER)
*
Apple Partition Map (APM)
*
BSD disklabel
In BSD-derived computer operating systems (including NetBSD, OpenBSD, FreeBSD and DragonFly BSD) and in related operating systems such as SunOS, a disklabel is a record stored on a data storage device such as a hard disk that contains informatio ...
External links
The .ADF (Amiga Disk File) format FAQ; 6. The structure of a hard disksPrints out information stored in RigidDiskBlocks of any device
including source
Amiga
AmigaOS
MorphOS
Booting
Disk partitions
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