Data General AViiON 4600 Series, Customer Documentation

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Using the System Control Monitor
B-10
014–002091
BOOT (cont)
Specifying a Device Unit: Second Parameter
The second parameter ( unit ) specifies the identification number of the device on the
specified controller. Different controller types have a different unit parameter. As
shown in Table B-5, the
unit parameter for your SCSI devices is the SCSI ID number.
Logical numbering for the unit parameter begins at 0 and is determined by
configuration jumpers. By omitting the second parameter, you specify the first unit for
that device type (that is, SCSI ID 0).
Table B-5 defines factory-default SCSI ID numbering for bootable devices on AViiON
systems.
Table B–5 Default SCSI Device ID and LUN Numbers
Drive SCSI ID LUN
First disk 1 0 N/A
Second disk 1 N/A
Third disk 2 N/A
First cartridge tape 4 N/A
Second cartridge tape 5 N/A
Third cartridge tape 6 N/A
1
Hard disk drives include Winchester and CD-ROM types.
Specifying a Logical Unit: Third Parameter
The third parameter specifies a drive's logical unit number (LUN). You rarely use the
third parameter (
lun# ); it supplies additional information when the second parameter
( unit ) does not uniquely identify the bootstrap device.
If you have more than one drive managed by the same SCSI adapter board, the drives
have the same SCSI ID number. The LUN differentiates drives managed by the same
SCSI adapter. As seen in Table B-5, two drives managed by the same adapter will
have the same SCSI ID, but different LUNs.
Second–Stage Argument
Typically, the first-stage boot brings up the operating system second-stage bootstrap.
The secondĆstage bootstrap uses any text it finds after the device specification in the
boot path to bring up and properly initialize your operating system. You can use this
second stage, or
file path , argument to specify any executable file or program
parameter (such as run level).
To specify a file path, append its specification just after the device specification (do not
type a space after the right parenthesis), as described in the following subsections.