Hardware Reference
In-Depth Information
can later lead to data loss when the user no longer remembers what parameters he used
during setup.
The Identify Drive data can tell you many things about your drive, including the follow-
ing:
• Number of logical block addresses available using LBA mode
• Number of physical cylinders, heads, and sectors available in P-CHS mode
•Numberoflogicalcylinders,heads,andsectorsinthecurrenttranslationL-CHSmode
• Transfer modes (and speeds) supported
• Manufacturer and model number
• Internal firmware revision
• Serial number
• Buffer type/size, indicating sector buffering or caching capabilities
Several freely available programs can execute this command and report the information
onscreen, including ATAINF, which is available as part of a free collection of diagnostic
tools called the Ultimate Boot CD. You can download the entire disc or most of the util-
ities individually from
www.ultimatebootcd.com/
. I find these programs especially useful
when I am trying to install ATA drives on a system that has a user-defined drive type but
doesn't support autodetection and I need to know the correct parameters for a user-defin-
able BIOS type. These programs get the information directly from the drive.
Two other important commands are the Read Multiple and Write Multiple commands.
These commands permit multiple-sector data transfers and, when combined with block-
modePIOcapabilitiesinthesystem,canresultinincredibledata-transferratesmanytimes
faster than single-sector PIO transfers. Some older systems require you to select the cor-
rect number of sectors the drive supports, but most recent systems automatically determ-
ine this information for you.
Manyotherenhancedcommandsareavailable,includingroomforagivendrivemanufac-
turer to implement what are called
vendor-unique
commands. Certain vendors often use
these commands for features unique to that vendor. Often, vendor-unique commands con-
trol features such as low-level formatting and defect management. This is why low-level
format programs can be so specific to a particular manufacturer's ATA drives and why
many manufacturers make their own LLF programs available.
ATA Security Mode
Support for hard disk passwords (called
ATA Security Mode
) was added to the ATA-3
specification in 1995. The proposal adopted in the ATA specification was originally from
