A+ Certification / Beginners

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ARC pathnames

Advanced RISC Computing Specification (ARC) is a rigid set of standards that has been presented by the ACE (Advanced Computing Environment) initiative. This initiative has been sponsored by major vendors in the industry, and one of the standards that arose was a naming convention to refer to disk partitions. To understand the parts of this name, refer to Table below.

ARC Path Components

Tyoe	Class	Description
SCSI	Adapter	This is the ordinal number of the SCSI controller that is located in the system. The ordinal number refers to the order in which the controller was located. The hardware is scanned according to the buses that exist on the motherboard, and each bus is scanned starting with slot number 1. If controllers were located in slots 1 and 3, then the controller in slot 1 would be SCSI(0) and the controller in slot 3 would be SCSI(1). SCSI is only used in cases where the SCSI controller either does not have an on-board BIOS, or is disabled.
multi	Adapter	The ordinal number of the Multifunction controller in the system. Multifunction is used for all devices that do not use the previous listing for SCSI. This includes IDE controllers and SCSI controllers with the BIOS enabled.
Signature	Non-Classed	This notation can be used in place of SCSI or Multi, in order to help conform to Plug and Play specifications. Each drive that is identified by the Windows XP OS has a Signature written to it. The signature notation looks like Signature(8765bfa4), and tells ntldr to look for a drive that has that signature and load the OS from there, regardless of which controller it happens to be found on.
disk	Controller	The SCSI ID number that has been assigned to the SCSI drive on the system. This is set to 0 when using the Multi (multifunction) adapter.
rdisk	Peripheral	The rigid disk number, referring to the physical location on the controller rather than the logical ID. The SCSI ID number refers to a logical ID.
partition	Block Device	The partition number for the partition that the OS will be found on. Partition(0) would refer to a drive with no partitions. Since Windows XP requires a partitioned drive to store files, the partition number will always be 1 or greater.

In the code from Listing-1 in the previous section, multi(0) referred to the first non-SCSI controller on the system; disk(0) did not refer to anything, as it would be a SCSI ID of a disk; rdisk(0) referred to the first disk on the controller; and partition(4) would be the fourth partition on the disk. Windows XP uses this specification since the assignment of drive letters to partitions is flexible, but partition locations are very rigid, thus preventing errors.