[rescue] ultra-1 question

[Lionel Peterson]

Fromthe file cited below:

# Copyright 1998 Sun Microsystems, Inc.
# All Rights Reserved.
#
# /platform/sun4u/boot.conf
#
# name/value pairs used to augment boot(1M) policy.
#
# ALLOW_64BIT_KERNEL_ON_UltraSPARC_1_CPU
#
# On systems containing 200MHz or lower UltraSPARC-I processors,
# it is possible for a user to run a 64-bit program designed to exploit
a
# problem that could cause the processor to stall.  Since 64-bit
programs
# cannot run on the 32-bit kernel, the 32-bit kernel is chosen as the
# default boot file on these systems.
#
# The code sequence that exploits the problem is very unusual and is
not
# likely to be generated by a compiler.  Assembler code had to be
# specifically written to demonstrate the problem. It is highly
unlikely
# that a legitimate handwritten assembler routine would use this code
sequence.
#
#
# Users willing to assume the risk that a user might accidentally or
# deliberately run a program designed to cause a processor to stall
# may choose to run the 64-bit kernel by uncommenting the following
item:
#
ALLOW_64BIT_KERNEL_ON_UltraSPARC_1_CPU=true

The above shows the line uncommented, thus allowing the Ultra 1 to boot
in 64 bit mode. As shipped by Sun, that file has the last line
commented out.

OBP needs to be 3.11 or greater, and as Dave said, if that is an issue
with the machine in question, the OS will offer to update it - but, a
jumper will need to be set allowing the OBP to be rewritten.

Enjoy,

Lionel

--- Dave McGuire <mcguire at neurotica.com> wrote:
>    Other folks have adequately explained why this machine defaults to
> 
> 32-bit mode...as far as actually changing it to 64-bit mode though, 
> edit /platform/sun4u/boot.conf...The variable to set will be obvious.
> 
>    As others have also mentioned, you may need to upgrade OBP for
> this 
> to work.  A Solaris install will offer to do this for you, though I 
> don't know offhand how to do it manually.


=====
Lionel

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