Personal Computer User Manual

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PPCBug Firmware
3
Refer to the PPCBug Firmware Package User's Manual for a description
of the use of ENV. Additional information on registers in the Universe
ASIC that affect these parameters is contained in your MVME5100
Programmer’s Reference Guide, listed in Appendix C, Related
Documentation.
Listed and described below are the parameters that you can configure
using ENV. The default values shown were those in effect when this
publication went to print.
Configuring the PPCBug Parameters
The parameters that can be configured using ENV are:
Bug or System environment [B/S] = B?
Maximum Memory Usage (MB,0=AUTO) = 1?
This parameter specifies the maximum number of megabytes the bug is
allowed to use. Allocation begins at the top of physical memory and
expands downward as more memory is required until the maximum value
is reached.
If a value of zero is specified, memory will continue to be increased as
needed until half of the available memory is consumed (that is, 32MB in a
64MB system). This mode is useful for determining the full memory
required for a specific configuration. Once this is determined, a hard value
may be given to the parameter and it is guaranteed that no memory will be
used over this amount.
The default value for this parameter is one.
B Bug is the mode where no system type of support is
displayed. However, system-related items are still
available. (Default)
S System is the standard mode of operation, and is the
default mode if NVRAM should fail. System mode is
defined in the PPCBug Firmware Package User's
Manual listed in Appendix C, Related
Documentation.