OC-misc/partition/README.md

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2020-02-19 18:39:48 +11:00
# Simple partition table format
This document specifies a general partition table format suitable for both unmanaged disks, and tapes.
## Partition table
The partition table resides at the end of the disk - the last sector of the disk, for several reasons:
- Ease of implementation for firmware to load from first partition
- Compatibility with existing partition table formats
The partition table takes one sector (512 bytes) and is divided into 16 entries, 32 bytes each.
### Partition entry
Each entry consists of:
- A 20 byte name field, padded with null characters.
- A 4 byte type field. This can be used either as a number or a string.
- A 4-byte start sector field.
- A 4-byte length field.
Any entry with no name should be ignored.
## Tape considerations
It may prove easier to use a tape if one were to implement a virtual drive component that maps to the data on a tape.
## Booting
It is suggested that firmware loads and runs the first partition with type "boot". More advanced booting logic may be implemented if desired.