Appendix C Hard Drives; Device 0/Device 1 Relationship; Smart; Automatic Soft-Drive Types - Compaq Deskpro EN Series Maintenance & Service Manual

C
appendix
HARD DRIVES
Compaq Computer Corporation uses IDE hard disk drives that conform to two different
primary/secondary implementations. These are Conner mode and ATA-compatible mode. These
two modes are incompatible with one another.

Device 0/Device 1 Relationship

A device 0/device 1 relationship exists when there are two hard drives connected to a single port.
In this situation, one drive must be designated as the device 0, or primary drive and the other as
the device 1, or secondary drive. This designation is necessary because both drives cannot work
simultaneously.

SMART

The SMART IDE hard drives for the Compaq Deskpro Personal Computers have built-in drive
failure prediction that warns the user or the network administrator of an impending failure or crash
of the hard drive.

Automatic Soft-Drive Types

An automatic soft-drive type is a mechanism where the system ROM and Computer Setup
automatically build a soft-drive type to provide support for IDE hard drives that are not in the hard
drive parameter table.
The soft-drive types are assigned according to the table below:
Drive
0
1
0
1
For hard drives that are greater than 528 MB, the system automatically translates the hard drive
parameter for DOS by logically halving the cylinders and doubling the heads. This allows DOS to
access greater than 528 MB. The translated hard drive parameters are put into the hard drive
parameter table in the shadow RAM copy of the system ROM. When using any operating system
other than DOS, you must use F10 Setup to set up the hard drive parameter table without
translation.
Hard Drive Type
65
66
68
15
Controller
Primary
Primary
Secondary
Secondary
Compaq Deskpro EN Series, Small Form Factor and Net PC Models C-1