HP Vectra VE5 3 Series Technical Reference Manual page 27

Disk Capacity Versus
Modes of Addressing
The three DMA modes allow the following transfer rates:
Mode
Cycle time (ns)
Transfer rate (MBytes/s)
Operated in slave mode, the IDE controller saturates the PCI bus with
transfers, thus limiting the actual achieved transfer rate to 10 MBytes per
second. Operated in master mode, though, the IDE controller is allowed to
work autonomously of the processor, and the full 16.7 MBytes per second
transfer rate can be achieved, with less than 33% occupancy of the PCI bus
(so allowing the processor to get on with other work for more than 67% of
the cycle times, whilst the IDE transfers are going on in parallel).
The amount of addressable space on a hard disk is limited by three factors:
the physical size of the hard disk, the addressing limit of the IDE hardware,
and the addressing limit of the BIOS. The Extended-CHS addressing scheme
allows larger disk capacities to be addressed than under CHS, by performing
a translation (for example regrouping the sectors so that there are twice as
many logical tracks as is possible under the CHS addressing scheme).
Cylinders per
Device
CHS 64
ECHS 64
LBA -
If the Setup field has been set to
(LBA) mode will be selected for each device that supports it.
0 1
480 150
4.2 13.3
Heads per
Sectors per Track
Cylinder
16 1024
256 1024
- 256 M (=2
automatic
2 System Board
Devices on the PCI Bus
2
120
16.7
Bytes per
Sector
512
512
28
) 512
, the logical block addressing
Bytes per
Device
528 M
8.4 G
137 G
19