UPGRADING REPAIRING PCs

Improving Hard Disk Speed 107
Figure 4.4 Normal (top) and Alternative (bottom) jumpers for Western
Digital 32GB or larger IDE hard disks with 10-pin jumper blocks.
The Alternate configurations (bottom)are used to limit the drive’s
reported capacity to less than 32GB. This configuration is required
if installing a drive with more than 32GB of capacity causes the
system to lock up because of BIOS incompatibilities. This condition
affects many systems with BIOS dates before 6/1/1999. While
jumpering details vary from brand to brand, two jumper blocks are
used in almost all cases.
A drive configured this way requires the use of EZ-Drive, MAXBlast,
or other drive-manufacturer–supplied disk utility programs to
access the full capacity of the drive. In some cases, the system
might need to be shut down at the end of a session rather than
warm-booted. Check with the drive manufacturer for details on
using this configuration with Windows NT/2000 or with Linux,
UNIX, or Novell NetWare.
Improving Hard Disk Speed
Although the ATA-2/EIDE standard is best known for establishing
LBA mode as a means of allowing larger hard drives to be used on
the IDE interface, a second major benefit of ATA-2/EIDE was
improving data transfer rates, as shown in Table 4.10.
Table 4.10 PIO Modes and Transfer Rates
Cycle Time Transfer Rate
PIO Mode (ns) (MB/Sec) Specification
0 600 3.33 ATA
1 383 5.22 ATA
2 240 8.33 ATA
3 180 11.11 ATA-2, EIDE, fast-ATA
4 120 16.67 ATA-2, EIDE, fast-ATA
PIO modes 0–2 could be achieved with the original 16-bit motherboard
or expansion slot-based IDE/ATA host adapters, but PIO