SEGA Partition Structure

Games on the Ring* series use MBR partitioned drives. The core partition structure is as follows:

Partition Size Format Content
1 1.5GiB NTFS Windows XP Embedded 2009
2 1.5GiB NTFS Windows recovery partition
3 remaining space Extended Partition (LBA) Game data

Extended partitions are structed by a linked list of partition headers at the beginning of each partition. These headers reserve 3Fh blocks for their information, however only use a single block at the start of this for actual data. SEGA make use of the remaining blocks in the first extended partition header for SEGA boot records.

Partition offset (blocks) Content
0 Extended partition header
1 SEGA Partition Description
2 SEGA Boot Record (1)
3 SEGA Boot Record (2)
4-63 Additional data storage
64-... Actual partition data

Two identical copies of the SEGA Boot Record are present. This is for redundancy; if either is corrupted, an attempt will be made to restore it from the other copy.

SEGA Partition Description

The SEGA Partition Description (SPD) largely echos the structure laid out by the extended partition headers, however is the table SEGA loaders preferentially read. It takes up all 512 bytes of the block; it's structure is as follows:

0 1 2 3 4 5 6 7 8 9 A B C D E F
00h CRC32 Ver
10h Slot content ? Block size Block count
20h Slot content ? Block size Block count
30h Slot content ? Block size Block count
F0h Slot content ? Block size Block count

The slot content types are:

Value Meaning
10h original0
11h original1
20h patch0
21h patch1
30h os
40h app_data

SEGA Boot Record

The SEGA Boot Record (SBR) contains detailed information about the content of each slot.

0 1 2 3 4 5 6 7 8 9 A B C D E F
00h CRC32 Ver
20h Bootslot 5x slot status