I think it's because the ARC uses the multi(0) parameter. The following is direct from Microsoft. If I understand it correctly, your boot.ini is using the machine's BIOS to tell it where to boot form. See if you agree:
MULTI(X) Syntax
The MULTI(X) syntax of the ARC path is only used on x86-based computers. In Windows NT version 3.1 this path is only valid for IDE and ESDI drives; in Windows NT version 3.5, 3.51 and 4.0 it is valid for SCSI drives as well.
The MULTI() syntax indicates to Windows NT that it should rely on the computers BIOS to load system files. This means that the operating system will be using interrupt (INT) 13 BIOS calls to find and load NTOSKRNL.EXE and any other files needed to boot Windows NT.
The X, Y, Z, and W parameters have the following meaning:
• X is the ordinal number of the adapter and should always be 0 (see the text below for the reason).
• Y is always 0 (zero) if the ARC path starts with MULTI(), because MULTI() invokes the INT 13 call as described above and therefore does not need the DISK() parameter information.
• Z is the ordinal for the disk on the adapter and is usually a number between 0 and 3.
• W is the partition number. All partitions receive a number except for type 5 (MS-DOS Extended) and type 0 (unused) partitions, with primary partitions being numbered first and then logical drives. NOTE: The first valid number for W is 1, as opposed to X, Y, and Z which start at 0 (zero).
Theoretically, this syntax could be used to start Windows NT on any drive in the system. However, this would require that all drives are correctly identified through the standard INT 13 interface; since support for this varies from disk controller to disk controller and most system BIOS only identify a single disk controller through INT 13, in practice it is only safe to use this syntax to start Windows NT from the first two drives connected to the primary disk controller, or the first four drives in the case of a dual-channel EIDE controller.
In a pure IDE system, the MULTI() syntax will work for up to the four drives maximum on the primary and secondary channels of a dual-channel controller.
In a pure SCSI system, the MULTI() syntax will work for the first two drives on the first SCSI controller (that is, the controller whose BIOS loads first).
In a mixed SCSI and IDE system, the MULTI() syntax will work only for the IDE drives on the first controller.
Back to the top
SCSI(X) Syntax
The SCSI() syntax is used on both RISC and x86-based computers and is used in all versions of Windows NT. Using SCSI() notation indicates that Windows NT will load a boot device driver and use that driver to access the boot partition.
On an x86-based computer, the device driver used is NTBOOTDD.SYS, which can be found in the root of the system drive (generally of drive C) and is a copy of the device driver for the drive controller in use.
On a RISC computer, the driver is built into the firmware as required by the RISC standards, so no file is required.
The X, Y, Z, and W parameters have the following meaning when using the SCSI() syntax:
• X is the ordinal number of the adapter as identified by the NTBOOTDD.SYS driver.
• Y is the SCSI ID of the target disk.
• Z is the SCSI logical unit number (LUN) of the target disk. This number is almost always 0 (zero).
• W is the partition number. All partitions receive a number except for type 5 (MS-DOS Extended) and type 0 (unused) partitions, with primary partitions being numbered first and then logical drives.
NOTE: This first valid number for W is 1, as opposed to X, Y, and Z which start with 0.
When using SCSI() notation the value of X depends upon NTBOOTDD.SYS. Each SCSI driver under Windows NT has its own method of ordering controllers, although generally they conform to the order that the BIOS on the controllers load (that is, if the BIOS is loaded).
Additionally, if you have multiple controllers that use different device drivers, you should only count those controlled by NTBOOTDD.SYS when determining the value of the X parameter. For instance, if you have an Adaptec 2940 (which uses the driver AIC78XX.SYS) and an Adaptec 1542 (which uses AHA154X.SYS) X will always be 0. What will change is the NTBOOTDD.SYS file:
