Problem with yaboot on 333MHz iMac

[Michael Jaffe]

I found the source of my problem and have solved it.

The Open Firmware of early iMacs and Power Macs cannot "see" beyond the
first 8 gigabytes of physical storage memory address space.  Any code
to be accessed from open firmware, including yaboot, has to
*physically* (not just "logically") reside within the first 8 GB of
addressible memory.  I've found that the /root partition of Linux needs
to be located within the first 8GB of physical address space as well
(your mileage may vary).

Developers of LinuxPPC installers should take this limitation into
account, especially as the early iMacs were very popular.

My partition table is now set up as follows:

 #:                type name               length  base      ( size )
1: Apple_partition_map Apple                  63 @ 1 
2:    Apple_Driver_ATA*Macintosh              54 @ 64
3:    Apple_Driver_ATA*Macintosh              74 @ 118      
4:       Apple_Patches Patch Partition       512 @ 192      
5:     Apple_Bootstrap bootstrap            1600 @ 704      
6:     Apple_UNIX_SVR2 root              4585472 @ 2304      (  2.2G)
7:     Apple_UNIX_SVR2 swap               737728 @ 4587776   (360.2M)
8:           Apple_HFS untitled 2       98304000 @ 5325504   ( 46.9G)
9:     Apple_UNIX_SVR2 home             12582912 @ 103629504 (  6.0G)
10:     Apple_UNIX_SVR2 usr             29360128 @ 116212416 ( 14.0G)
11:     Apple_UNIX_SVR2 tmp              2097152 @ 145572544 (  1.0G)
12:     Apple_UNIX_SVR2 var              8631792 @ 147669696 (  4.1G)

Interested parties should read the Apple Developer document at
http://docs.info.apple.com/article.html?artnum=106235

I spent about a week hunting down this little tidbit.  If you know of
anyone having booting problems with any of the following computers,
please let them know about the 8 GB boot limitation.

PowerBook G3 Series, excluding PowerBook G3 Series (Bronze Keyboard).
See Related documents below.
Power Macintosh G3 Desktop
Power Macintosh G3 Mini Tower
Power Macintosh G3 All-In-One
Macintosh Server G3
iMac 233 MHz
iMac 233 MHz/B
iMac 266 MHz
iMac 333 MHz

Michael Jaffe

--- Michael Jaffe <jmichaeljaffe@yahoo.com> wrote:
> 
> I have been trying to boot linux on my 333MHz (Rev. D, I think) iMac
> for about 2.5 weeks now.  No problems installing.  I've tried Debian,
> SuSE, and YDL.  Each time, after installing, I can't boot.  I've
> booted
> into Open Firmware and zapped the PRAM so often I can find the keys
> blindfolded.


=====
-------------------------------------------
J. Michael Jaffe, Ph.D.
jmjaffe@research.haifa.ac.il
phone: +972 4 6398160
fax: +972 153 4 6398160

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