Maxtor DiamondMax 21 Manual page 46

Note.
See the bit descriptions below for words 63, 88, and 93 of the Identify Drive data.
Description (if bit is set to 1)
Bit Word 63
0 Multiword DMA mode 0 is supported.
1 Multiword DMA mode 1 is supported.
2 Multiword DMA mode 2 is supported.
8 Multiword DMA mode 0 is currently active.
9 Multiword DMA mode 1 is currently active.
10 Multiword DMA mode 2 is currently active.
Bit Word 88
0 Ultra DMA mode 0 is supported.
1 Ultra DMA mode 1 is supported.
2 Ultra DMA mode 2 is supported.
3 Ultra DMA mode 3 is supported.
4 Ultra DMA mode 4 is supported.
5 Ultra DMA mode 5 is supported.
6 Ultra DMA mode 6 is supported.
8 Ultra DMA mode 0 is currently active.
9 Ultra DMA mode 1 is currently active.
10 Ultra DMA mode 2 is currently active.
11 Ultra DMA mode 3 is currently active.
12 Ultra DMA mode 4 is currently active.
13 Ultra DMA mode 5 is currently active.
14 Ultra DMA mode 6 is currently active.
38 DiamondMax 21 Serial ATA Product Manual, Rev. A