Panasonic JB-3300 Technical Manual page 412

Dual buffer
When a dual buffer is used for the HDC, the host side's DMA transmission
speed can be as fast (but not faster) than the disk drive's transmission
speed, and even when the multisector mode is used, on-sector interleave
transmission is possible with the host side's DMA transmission speed.
o DMA transmission speed can be as fast (but not faster) then the disk
drive's transmission speed.
o The load for the host side hardware is light.
o Cycle stealing and high-priority processing is possible for the host
side. an
o Processing efficiency does not decrease when the multisector mode is
used.
Example: Read data (from disk to host)
Disk drive transmission speed: 5M bit/s (1.6 us/byte)
Host computer transmission speed: 3.2 us/byte
| SECTOR
4
SECTOR |},epreave [SECTOR 2 SECTOR 3 SECTOR
SECTOR| DATA SECTOR 3 DATA
DISK DISK ,
BUFO |—=BuFo —~ BUF O
| SECTOR I DATA
+ SECTOR 3 DATA
BUF O - HOST
BUF O—HOST
SECTOR 4
SECTOR 2 DATA
DATA
DISK : DISK
BUF | —> BUF | | '—~ BUF |
y SECTOR 2 DATA
BUF | ~» HOST
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