Open Firmware MP specifications?

Hello! I'm trying to figure out how kernel code interacts with the Open Firmware in order to activate/deactivate processors on a multiprocessor machine. Also, I'd like to know how CPU contexts are loaded into CPUs.
I have read through IEEE1275.1994 and found no mention except for an indication that "typically, on a multiprocessor system, the firmware initialization, booting, and operating system configuration steps all execute on a single processor, and the operating system enables multiprocessor mode only after those steps are complete."
Is there any document that specifically describes the interface the Open Firmware exposes to allow kernel code to access and control multiple processors on (Ultra)SPARC? I'm running an E4500, if that helps.

Since there is no Open Firmware, there's no reason to reset the Open Firmware defaults. I would assume that since there's no current interface to reset the EFI defaults, this operation is not necessary. I can't say that for certain. But, just like "zapping the PRAM", which used to help when troubleshooting issues with Mac OS 9, doing it in Mac OS X doesn't change or affect as many settings so it's really not necessary.
-Doug

Similar Messages

Console Mode with third-party PCI card w/ open firmware bios,Open Boot Info

PPC macs used open firmware to boot, and their videocards contained forth code in their rom. There are even custom roms for PC video cards which contain code for the PPC mac open firmware.
Could such a card be initialized as the primary display device on an Ultra 5?
I'm betting I'm going to be answered with 'use a sun branded card'. I can't imagine the rom on these cards is so much different than that used on the PPC mac?
What exactly does Open Boot do to find a videocard? Are there any documents on this? I assume it finds some forth routine in the cards rom and runs that to initialize it and identify it's capabilities? Again, I would really appreciate some direction on where to look for docs.
I'm confused on the difference between openfirmware (apparently a spec), and open boot (sun's implementation? Are all implementations compatible with eachother?)
http://www.openbios.org/Welcome_to_OpenBIOS
"Open Firmware is found on many servers and workstations and there are several commercial implementations from SUN, Firmworks, CodeGen, Apple, IBM and others."
Additionaly, what is the sun4u architecture? sun4v architecture? Which workstations are which? System handbook doesn't seem to say under 'hardware specs'.
So, if all else fails and using a card with an openfirmware rom doesn't help me, how do I go about doing this myself?
I know how to work VGA console mode via the stardard vga registers, Is there a way to get open boot to do exactly what I tell it in terms of registers and addresses?
Can I get an uncompiled form of my Open Boot Prom for my Ultra 5?
All I'm really looking for is good docs/source on how Open Boot/ Open Firmware work, specificly conerning PCI video devices.
Thanks for any tips.

I haven't looked at anything beyond the OpenBoot level.
I've been neglecting this project for some time.
I just wanted to let anyone else in my situation know that the sun OpenBoot documentation was very helpfull in my sucessfully setting a mode with the card.
I don't know how the OS and later OpenWidows interact with the card, or with the information OpenBoot has about it, and it's current mode.
I hadn't really looked at any of that yet. Though this information will probably show up as soon as I bother to look for it, it'd be nice if some one recommends a specific doc, or has a short answer about the topic.
There happens to be an open source driver for my card, for XFree86 and Xorg, however, I've had enough of a challenge merely using OpenWindows.
/etc/X11/xorg.conf /etc/X11/XFree86.conf
Where are simmilar files for OpenWindows? Again, it's probably in some docs I haven't bothered to read yet.
Sparcy: Weird that the card has Fcode and OpenBoot doesn't add it's package to the device tree. I assume it treats it like a non Fcode PCI card? Does it recognize the contents of the PCI base address registers? Try proding it's PCI registers and see if they behave as expected.
If the card is actually working and you can read the expansion rom I don't see why the Fcode didn't work. Maybe it has a later incompatible Fcode revision? Open boot 4.x 5.x? sun4u as opposed to something else? Or maybe the Fcode was designed to lock the card to a certain type of system (I doubt that).
http://www.sunshack.org/data/bootroms.html
Newer versions of openboot, and new hardware series listed at that link. Where's a more complete list?
Oh well, I guess I should bother to read up on this more thoroughly and finish the job.
Let me know if you find out what the problem was, or if you try that MAC card. Thanks.

Beige G3 boot from **** problem; open firmware issues; bad motherboard?

Dear all,
I'm having huge boot/startup problems with my beige G3 that had been happily running OSX 10.3.9, but for purposes of this discussion we can (mostly) revert to OS 9. Originally, the machine was a G3 @300; was upgraded more than a year ago to a ZIF G4 @500.
To make a long story short, it won't boot from any hard drives, will not boot from any OS X CD, and will only occasionally boot from a 9.x startup CD (whether Apple or Norton Utilities). I think it's an open firmware issue, possibly caused by a bad motherboard (rev. 2).
All this started happening after I used techtool pro, but I think that's coincidence (even though I acknowledge that, for cops and computer users, there are no coincidences.) Also, as discussed below, I'm having the same problems with an HD that wasn't even in the computer when all these things began.
Here are some of the things I've done.
--repeatedly reset PRAM, both with key combinations and removing battery. The only time it will boot from a 9.x CD is after resetting PRAM.
--removed all add-on PCI cards.
--removed additional VRAM
--removed all memory cards and tried replacing one at a time.
--disconnected both existing hard drives and replaced with an older OS 9.x hard drive (approx 60 mb) that I'd used before. Also tried different ribbon cables.
--unplugged floppy drive
--disconnected PCI ATA disk controller that I'd been using for running a large (1.8 gb) hard drive.
--regarding open firmware: readenv usually shows totally normal default AND installed settings. Using reset-all works fine -- at least it makes the machine reboot, but doesn't solve the problem. reset-nvram does NOT work -- says it's an "unknown word."
--using startup keys like holding down the option key, or shift key, or X key or cmd-option plus two others I can't remember, has no effect. Again, after I've tried any kind of reboot, the ONLY way to get the C-key at startup to boot the CD is by resetting the pram (key combination). Otherwise, the usual result of these experiments is a dark screen on startup -- nothing at all (and the LCD monitor tells me "no input.")
--regarding OSX: sometimes (and I emphasize sometimes) I can get the machine to start booting from an OSX 10.2 CD, but it won't complete the process. Sometimes I get a "prohibited" (as in no-parking, no-smoking) icon; sometimes it will start booting (grey screen, OS X Apple icon), then crash (horizontal grey and white jagged bars); sometimes it will show the OS 9 start icon (the tiny smiling Mac SE), but not boot at all.
--when I get the mac successfully booted with an OS 9.x CD (again, this works sometimes, but not always), the old hard drive with two partitions does show on the desktop and can be accessed. Using either disk repair or Norton Utilities shows the 9.2 system partition on the hard drive to be fine. But if I go to the startup disk control panel, confidently set the 9.2 partition as my startup disk, then reboot, there's no change. It won't boot and I'm back at square one.
--even when I do get successfully booted with 9.x, the machine will still occasionally crash for no reason -- ie when I'm moving a Window.
--the only thing I haven't done is slowed down the processor. It's a ZIF G4 bought more than a year ago from XLR8 your Mac. I'm running at the default 500 mhz, and it's never given me any trouble.
So I think it's a bad motherboard or ROM. Thoughts?
Thanks.

The beige Mac is now operating happily again. My original tentative diagnosis remains the same (although still tentative): corrupted PRAM from bad battery, compounded by bad cables that wrote corrupted data to hard drives, and also (possibly) allowing Tech Tool Pro (a utility that I now regard with deep suspicion) to create a "virtual" startup partition.
A few things I've learned along the way that hopefully may be useful:
--remember that the Ex Post Facto utility can be used to help OS X startup, not just installation. This applies to hard drives, emergency CDs, installation CDs, etc. If you can boot into any working hard drive partition (OS 9 or a backup OS 10), then run Ex Post Facto (same program runs on either OS 9 or X -- don't ask me how) and tell it what system you want to start up from. Also, the utility has sometimes told me that the startup extensions on the disc that I wanted to boot up from were bad, and offered to fix them (which works).
--at least on my Mac (beige, v. 2 motherboard), resetting the CUDA button, resetting the PRAM, resetting Open Firmware and "draining" the memory by unplugging the computer and disconnecting the battery for several hours ALL DO DIFFERENT THINGS.
Specifically, if I'm having trouble booting (from a hard drive or a CD), the FIRST thing I do is restart and resetting the PRAM on the fly -- holding down command, option, P and R at startup, and waiting for the chimes (preferably at least 3-4 times).
If I do that and DON'T hear the chimes, that's my cue for my SECOND action -- restarting into open firmware (command, option O and F keys on startup). That should bring up the black text on white background open firmware screen. View other posts or apple support for details, but if you do PRINTENV and see a bunch of weird gibberish after the default/installed lists, you know that it was messed up and you need to clear it through reset nvram and reset all commands. Be aware some of these commands do or do not work depending upon what version of Open Firmware you have.
After I've rebooted with Open Firmware, then on restart I should be able to reset the PRAM on the fly. If that works, then either let the machine run and see what happens, or hold down the C command and see if it will boot from the CD
Usually, if I've fixed everything as above, the machine will boot into whatever version of OS 9 it finds on a hard drive. That's fine with me -- at that point, use Ex Post Facto to reboot into your OS X. (Before I forget: I used the shareware startup CD creator program BootCD to make an emergency boot CD based on OS 10.2.8 (which theoretically will support a beige mac in native fashion) and Disk Warrior, the god of disk repair utilities. Even though the CD should boot just by holding down the C key on startup, it doesn't -- but if I use Ex Post Facto to boot it, no problems (although the process is very slow -- be patient). Then I can fix almost anything using Disk Warrior.)
If none of the above works, then I'll try resetting the CUDA (on my beige minitower, it's a very small black button inconveniently located between a PCI slot and the side of the computer housing). Hold it down for 15 seconds. That should REALLY clear the PRAM. I know this does something different from the previous steps because this is the only action (except the battery disconnect -- next) that clears the date and time from the memory.
If all else fails, I will unplug the computer and disconnect the battery, then push the CUDA button for 15 seconds and let the machine sit overnight.
One final finding -- I thought I'd fixed everything, but both my hard drives suddenly quit working, I discovered that during all this repeated connect/disconnect of things, one of the male pins inside one of the connectors on my Acard ATA PCI card had broken off. Not good. Fortunately, the card had a second connector, which works fine. And I did some extensive shaking of the computer to make sure (I hope) that the broken pin hadn't landed on a circuit board.
All this took more than two weeks, and the advice of this board was much appreciated. Now I'm on to my next adventure -- trying to figure out why a combo Firewire/USB PCI card won't mount an external drive on Firewire, but will on USB. I've tried two cards with same result -- but a Firewire-only card works just fine.)
Regards to all,
Graham

Rebooting in Open Firmware

I have a MacBook, with 10.5, and I've noticed that these MacBooks can no longer boot up in open apple firmware by holding down COMMAND-OPTION-O-F. I've tried it on two MacBooks and it didn't work on either. Is this a MacBook thing? Or a Leopard thing?

It's a Macbook, or more specifically, a Intel-based Mac, thing. Open Firmware is a PowerPC only thing, so that command is no longer used.

Open Firmware Can't boot my WinXP install disc (although the OS sees it)

So I've been unable to play ANY games on my MacBook Pro under Crossover (games that worked fine under my old 1.8Ghz MacBook Pro) because I get all sorts of weird graphical rendering issues.
So I thought I'd reboot into windows, install the games there, and see if the problems were related to Crossover or not.
So I launch Bootcamp Assistant to install Windows XP. I pop in the Windows XP disc (under MacOSX) and I see the disc and all the installer files, and I click to reboot into the Windows installer.
The laptop reboots and when it comes up I can hear it trying to read the cd. I can hear it switching speedings up and down and moving the read headers. But it never starts the installer, instead it spits out the disc and prompts me to insert a bootable disc.
Problem is I know this disc works. I've used it many times. And back over under MacOSX it reads the disc just fine.
So I know this "new" laptop I got from work was actually refurbished, and I think they messed with it. Specifically I wonder if they mess with the open firmware. Because again, MacOSX (the software) could see and read the disc just fine. But when I'm in the open firmware loader it can't read the disc.
Also, if I hold down Option at boot time, I get the option to select my WindowsXP disc because it sees it, but again, it can't load it...
Is this a 32-bit/64-bit issue? I don't know. All I know is I can't boot my XP CD to install XP....
Is there a way for me to reinstall the open firmware?

I've now tried my buddy's WindowsXP SP2 disc and the first time, it loaded the windows installer (boot and held down Option and selected the disc) but the install failed. On reboot the windows partition will not boot.
So I tried again, and now his disc and responding the same way my disc responds.
I reboot, hold down Option, select the Windows XP disc, and then the screen goes black. I hear it trying different speeds to read the disc, then finally it stops and spits the disc back out and tells me to insert a bootable disc.
So that's two separate WindowsXP install discs. Both are known to work.
So why can this drive see the disk and files just fine under MacOSX -but not- under the EFI bootloader?? And yes I've tried resetting the NVRAM/PRAM.
Message was edited by: general_error

Open Firmware Password; not on Snowy Upgrade DVD; how do I get hold of it?

hey;
my MBP15 came with 10.5 & i got the snowy upgrade dvd from apple; there's no Open Firmware Password utility on the upgrade DVD (i even searched using pacifist) and it cannot be downloaded from apple's downloads. this seems a serious omission since i protect my mac (somewhat) with it.
does anyone know how i can get it, since i think it's pretty product specific; if it's actually different from the version on the original 10.5 disk that shipped with the machine or would some kind soul with the same machine (MacBookPro5,1 MBP51.007E.B05) have to share it with me?

actually, don't trust me; i'm wrong.
thank you so much, roam! you do indeed have to boot from the dvd!
what had me fooled is that pacifist didn't find it, and it used to be a discrete file which you could simply drag from the utilities folder of the install disk on to your mac.
i have now enabled the firmware password!
thanks again!

Start-up problems, black screen or open firmware

My iBook G4 1.33GHz Dual USB, with 1 gb RAM memory has been troublesome lately. It's installed with the latest version of OS 10.4.9
When starting up the ibook, it will sometimes only show a black screen after the boot chime. Repeated force restart sometimes makes it boot up the open firmware (white screen).
Then I see the error message:
"Illegal instructions at: %SRR0:ff85e778 %SRR1:00081000"
When I continue on with "mac-boot", I get the blue screen with a question marked box. So it can't find the startup disk.
This usually only happens when I'm done working for the day and close the lid on my ibook without manually clicking on the sleep mode when I put in in my drawer,. I've seen several times that the screen is still on when I close the lid, so it will continue to burn battery time.
I've managed to get the ibook to boot properly after removing the battery and letting it "cool-down" for 15-20 min. Also, zapping pram, vram sometimes works, but I don't know how much that actually helped. It worked once when I typed in the reset-nvram in the open firmware screen too.
I'd rather not have this happen at all! Any suggestions? Is this the much-talked about RAM memory failure?
Any suggestions would be very appreciated.
Message was edited by: antony chen

HI,
*"I get the blue screen with a question marked box."*
That can mean several things. One, the drive is failing. Two, your iBook can't find a System Folder to boot from. Try booting while holding down the Option key which will prompt the Startup Manager window.
MemTest
Boot from your install disk and check the hard disk for errors.
Insert Installer disk and Restart, holding down the "C" key until grey Apple appears.
Go to Installer menu (Panther and earlier) or Utilities menu (Tiger and later) and launch Disk Utility.
Select your HDD (manufacturer ID) in the left panel.
Select First Aid in the Main panel.
(Check S.M.A.R.T Status of HDD at the bottom of right panel. It should say: Verified)
Click Repair Disk on the bottom right.
If DU reports disk does not need repairs quit DU and restart.
If DU reports errors Repair again and again until DU reports disk is repaired.
When you are finished with DU, from the Menu Bar, select Utilities/Startup Manager.
Select your start up disk and click Restart
While you have the Disk Utility window open, look at the bottom of the window where you see Capacity and Available. Make sure there is always 15% free disk space. Not enough disk space can cause directory corruption.
If you cannot boot from your install disk, try booting in Safe Mode
A flashing question mark appears when you start your Mac
Carolyn

PowerBook G4 boots to Open Firmware without keyboard access

Summary:
Let me provide a little backstory.
According to the [DARPA Visitor Guidelines|http://www.darpa.mil/body/visitor_guidelines.html] wireless network technology is prohibited from DARPA facilities. Laptops with a wireless card are required to be "disabled at the BIOS level".
Before an upcoming visit to DARPA I was told that I would need to make sure my laptop wireless card was disabled. I mentioned that Macs don't have BIOS but I'd look into doing it in Open Firmware. The response from DARPA was that no one has ever successfully brought an Apple laptop into the facility, and that I should procure a PC laptop for my visit. Ah, a challenge!
I booted into Open Firmware (⌘⌥OF), located the wireless card in the device tree, and removed two properties I figured the driver would be searching for: the vendor ID, and the product ID. I exited Open Firmware and continued to boot into Mac OS X v10.5.2.
Sure enough the System Profiler showed that no wireless card was installed. Success! Now I just need to make the device tree modifications persist between reboots.
It seemed the solution was to place the Open Firmware commands I issued to disable the card into nvramrc. So I set nvramrc to contain the same commands, and set use-nvramrc? to be true. I rebooted the machine but the card was still detected.
A bit [more research|http://docs.sun.com/app/docs/doc/805-4436/6j4719c8v?a=view] revealed that the device tree is not created by Open Firmware until after the nvramrc is executed. The solution is to build the device tree in the nvramrc and tell Open Firmware not to rebuild it. The documentation states that this is accomplished with the probe-all, install-console, and banner Forth commands. I added those commands to my nvramrc and rebooted. The contents of nvramrc:
probe-all install-console banner
dev wireless
" device-id" delete-property
" vendor-id" delete-property
The outcome... well technically the laptop has wireless disabled. Almost everything is disabled. The machine now boots directly into Open Firmware with a few ominous bits of output and no response from the keyboard.
no active package
Apple PowerBook5,6 6.4.9.1f1 BootROM built on 01/21/05 at 10:51:16
Copyright 1994-2005 Apple Computer, Inc.
All Rights Reserved.
Welcome to Open Firmware, the system time and date is 05/06/2008 10:00:00
Command security mode
To continue booting, type "mac-boot" and press return.
To shut down, type "shut-down" and press return.
ok
0 > _
The first sign that something has gone wrong is no active package. The second message just throws another wrench into the works: Command security mode. Yes, the Open Firmware password was enabled. In retrospect this was a bad thing to have set when mucking about in OF. I knew of the RAM change trick (see below) so this was not an issue at the time.
Question:
So the question is: What actions do I need to take to return the laptop to a useable state. That is, booting into Mac OS X.
*Attempted solutions:*
+1. Reset nvram+
The first and most obvious solution is to reset nvram using the snag key combination ⌘⌥PR. Unfortunately do to the firmware password being set, [all snag keys have been disabled|http://support.apple.com/kb/HT1352]. This means no target disk mode (⌘T), boot from CD (⌘C), boot from network (⌘N), etc... In any case an attempt at resetting nvram yields an additional message being appended to the Open Firmware screen:
Release keys to continue!_
+2. Reset nvram after changing amount RAM in system+
Luckily there is a work-around to firmware password protection. Changing the amount of RAM installed in the machine should allow the nvram zap snag to function. I removed one of the two 512MB DIMMS in the laptop and started up while holding down ⌘⌥PR. This results in the same message as above:
Release keys to continue!_
Not so lucky.
+3. Reset the Power Management Unit+
[Resetting the Power Management (PMU)|http://docs.info.apple.com/article.html?artnum=14449] is accomplished by removing the battery and disconnecting the power cord, and then holding down the power button for about 5 seconds. This had no effect besides resetting the system clock to 01/01/1904 00:00:41.
Getting more desperate...
+4. Search logic board for CUDA+
I [opened the machine|http://www.ifixit.com/Guide/Mac/PowerBook-G4-Al-15-Inch-1-5-1-67-BT-2-0 -LR/64] to search for a hidden [CUDA button|http://docs.info.apple.com/article.html?artnum=86760]. As expected, a CUDA button does not exist on this model and the PMU reset is accomplished as noted in attempted solution 3.
+5. Remove internal battery+
Well the laptop is open now, so I tried removing the internal memory backup battery and revisited each of the above solutions. No success.
+6. Remove hard drive+
Again, since the laptop was open, why not remove the hard drive and see what happens. The machine wasn't even making it to the boot-loader hand-off so I didn't expect this to produce any results. No results produced.
Thinking crazy thoughts...
+7. Attempt a firmware update+
Firmware updates have a side effect of resetting the nvram. Also firmware updates are initiated very early in the startup process by holding down the power button until a tone is heard and the power light flashes. My thought was that I would grab a previous firmware update for this laptop and force it to be reapplied. Unfortunately there have been no updates to this model's firmware.
+8. Write my own firmware update script+
While investigating solution #7 I realized that the file BootROMFirmware installed by the firmware updaters for G5s and G4s machines are just Forth programs with a binary payload attached to the end. I learned [Forth|http://en.wikipedia.org/wiki/Forth(programminglanguage)]. The BootROMFirmware files are really cool, since they do everything from drawing the progress bar during the update, uncompressing and check-summing the binary payload, and generally making sure you don't brick your machine. In any case it seem entirely doable to write my own program in Forth and undo the evil I did before. I really only need to flip one bit. I needed the use-nvramrc? variable set to false. So I created this very simple Forth program:
\ debrickifier
setenv use-nvramrc? false
reset-all
The original firmware file had additional attributes set, a creator and file type of fw99. So I set those two attributes on my file as well. I ran strings on the firmware installer program and guessed that it was copying the file to /System/Library/CoreServices. So this is where I placed my Forth file. Reinstalled the drive and rebooted the laptop while holding down the power key to initiate a firmware install. No dice.
Its hard to tell why this is failing. The file may in the wrong place, have the wrong permissions. From what I've reviewed in the original files, the setenv and reset-all words should be available. Maybe the Firmware Update utilities are setting some other magic in nvram before the reboot.
I think I've covered all the different major solutions that I've attempted. Their might be a few more that I've forgotten to mention (like using an external USB keyboard). I still think that getting some Forth to execute via the firmware update mechanism could use some more exploration. My current worst case is that I'll replace the logic board, although I'd hate to do that when I know there are only a few bad bits flipped in a CMOS somewhere.
I'm hoping to snag the attention of the resident hardware/firmware guru that can shed some light upon the firmware update process, but any help or suggestions would be greatly appreciated.
Cheers,
Mark

For your next DARPA visit, another option might be to buy the cheapest possible third-party wireless card — it doesn't even need to work. Insert it into your Powerbook's CardBus slot before visiting DARPA, and turn Airport off in System Prefs. On arrival at DARPA, remove the card from the Powerbook and hand it to the security guard. Retrieve it from the guard as you leave, and turn Airport back on again when you get home or back to your office. Unable to comply with the letter of the dunderheaded regulation because you have no BIOS, you will be complying with the spirit of it instead, and no one will be the wiser.

I am having a Startup problem. Someone comes on the screen with Open Firmware to Startup. How can I reset the PRAM myself to solve this problem?

I am having a Startup problem. Someone comes on the screen with Open Firmware to Startup. How can I reset the PRAM myself to solve this problem?

Read these.
http://support.apple.com/kb/HT1431
http://reviews.cnet.com/8301-13727_7-10330118-263.html

Start-up Problem - White Screen Open Firmware

Hi
Just turned my eMAc on and got a new beeping sound, the little light on the front flashed several times and then the screen went completely white with the following message;
Apple PowerMac 6,4 4.8.2f1 BootROM built on 03/11/04 at 09:18:55
Copyroght 1994 - 2004 Apple Computer, Inc.
All Rights Reserved
Welcome to Open Firmware, the system time and date is: 07:26:35 10/20/2006
To continue booting, type "mac-boot" and press return
To shut down, type "shut-down" and press return
ok
0 >
I typed in 'mac-boot' and return and everything starts and 'appears' to work as normal.
I have shut down and restarted twice and the same thing happens. I also noticed that the push button switch seems to be sticking.
My question is - Is this a hardware issue (the start button is faulty) or is it a software (firmware, corrupt file)?
Many thanks for help and advice
Mick

It's possible it's a hardware problem, but first I'd suggest you try resetting Open Firmware:
At the 0 > prompt, type:
reset-nvram
and press Return
At the 0 > prompt, type:
set-defaults
and press Return
At the 0 > prompt, type:
reset-all
and press Return.
With luck, that will clear things and you'll be back to booting normally.
Hope this helps.

Long tone on start up and then goes into open firmware

I stumbled upon the older posts here and thought I'd add a solution.
http://discussions.apple.com/thread.jspa?messageID=6115258
It was about an emac starting up with a long tone and the led flashes a few times and then goes into Open firmware, and when doing "mac-boot" in open firmware, it attempts to start, shows the apple symbol, the screen goes dim and crashes.
It could be a bad power switch. To confirm - you can remove the emac case, be careful not to touch the motitor's picture tube. Find the cable to the power switch; with a small wire just touch together the black and red wires on the power switch cable (or it might be red and green). This will start the emac. If it boots up and runs OK then the power switch was bad. Not sure where to buy a new switch. I soldered and glued my switch together.
<Edited by Moderator>

Or, you'll find both the short pigtail-cabled nVidia graphics driven power switch and the version with a longer cable used with the AIT graphics driven models here* for a good deal less.
Note that the later ATI version can actually be used with either product generation.
*I may receive compensation as a result of parts or services being ordered by users specified at the link shown in this message.

IBook G4 - Black screen in open firmware

Hi, i have a strange problem with my iBook G4.
When switched on it chimes and starts loading but the screen is completely black (not no backlight but completely black). In otherwords it does not show the grey screen or apple logo.
Once the OS boots the blue screen comes up and everything works perfectly.
So the problem is that anything before the actual OS loads is black. That means the grey screen with apple logo, open firmware and the drive selection screen (if you boot holding ALT/OPT) are all black.
I have tried resetting the PMU, Pram and blindly (with black screen) in open firmware did reset-nram and reset-all but nothing changed.
It is a late 2004 iBook G4 1.2Ghz with 512MB ram, 30GB HD and OSX Leopard 10.5.8.

This is a strange one, isn't it?
I'd count my lucky stars that it will boot into the OS, and I'd be saving up for a new MacBook Pro (or used MacBook).
I'm going to kick this one around with some of the gang in the Lounge and see if any of them have any ideas about what may be causing this.
Good luck with it.

How do I install an open firmware password on my 10.6.8 OSX Macbook?

I tried to download the lastes version of open firmware, but it is incompatible with the version of my computer. Don't tell me to use a disk I got with my computer, that would be for a Macbook Pro, not a Macbook, which is what I have. Please tell me if you can find a link to a firmware password program for Mac OSX 10.6.8, or if you have another way of installing a firmware password. Thanks.

You have other problems on your computer, then, or not reading carefully. Note this:
"For Mac OS X v10.5.x, start from the Leopard Install DVD and choose Firmware Password Utility from the Utilities menu, then skip to step 5."
For Snow Leopard if the above does not work, then look for the Firmware Password utility on your Snow Leopard DVD.
Oh, and please don't click on the Helpful or Solved buttons for your own posts.

Bug in Excel's handling of metadata? Or at least a deviation from the Open Office XML specification?

I've discovered some very strange behaviour in Excel which seems to be contrary to that documented in the Open Office XML specification (OOXML). I couldn't find a way to report bugs against Excel, so I thought I'd try to explain the issue here.
In short it seems that Excel is removing, and incorrectly re-indexing the metadata I programatically associate with cells.
First, a summary of the relevant parts of the specification:
From OOXML 18.9: There are two types of metadata: "cell metadata" and "value metadata".
Cell metadata follows the cell as it moves. Value metadata follows the value through formulae etc.
From OOXML 18.3.1.4: The c (cell) element has cm and vm attributes which are both documented as "The zero-based index of the [cell|value] metadata...in the Metadata Part"
From OOXML 18.9.17: The valueMetadata is "a collection of block element that each define the value metadata for a particular cell". "Cells in the workbook index into this collection".
The valueMetadata contains bk elements which in turn contain rc (metadata record) elements
From OOXML 18.9.15: rc elements have t (type index) and v (value index) attributes. t is a 1-based index into metadataTypes and v is a 0-based index into the futureMetadata element which matches the name of the metadata type.
Here's an example of what this might look like:
<c vm="0"> 
<x:valueMetadata>
<x:bk>
<x:rc t="1" v="0" /> 
</x:bk>
</x:valueMetadata>
<x:metadataTypes>
<x:metadataType name="MyMetaType" ... /> 
</x:metadataTypes>
<x:futureMetadata name="MyMetaType" ...>
<x:bk>
<x:extLst>
<x:ext xmlns:x="http://schemas.openxmlformats.org/spreadsheetml/2006/main" uri="http://example.com/extension" p5:value="test value" xmlns:p5="http://example.com/extension" />
</x:extLst>
</x:bk>
</x:futureMetadata>
The Problem
From what I can tell, for values of n > 2, if you associate n cells with metadata, Excel will drop the last piece of metadata, and the one at index 1, and it will do so silently. The indices are then 0..n-3, and the association for all but the first (0
index) will be wrong. This renders the future metadata totally useless.
For n == 1, Excel just removes the last piece of metadata (index 1). If we try 1-based indexes for the vm attribute on the c element, we get different behaviour. This may not be relevant as it is contrary to the specification, but the slightly better behaviour
might indicate an off-by-one error:
n
Deleted Indices (0-based) when using 0-based indices
Deleted Indices (0-based) when using 1-based indices
1
0
None
2
1
1
3
1,2
1
4
1,3
1
5
1,4
1
6
1,5
1
Demonstrating the Problem
I have some example code[1] that demonstrates the problem. You will need a file called test.xlsx with cells A1..C2 populated.
Compile the source as AddMetadata.exe then run with the test file as the only parameter:
> AddMetadata.exe test.xlsx
You can look at test.xlsx in Excel, Visual Studio (with the Open XML Package Editor Power Tool for Visual Studio 2010) or the Open XML SDK 2.0 Productivity Tool for Microsoft Office. Looking at the file before and after running AddMetadata.exe you should
be able to reproduce the behaviour documented above.
Summary
It would be good to know if this is really an Excel bug or whether we're doing something wrong / unsupported. Any insight would be very much appreciated.
[1] The Example code:
namespace AddMetadata
using System;
using System.Linq;
using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;
public class Program
// The cells to associate with metadata
private readonly static CellSpec[] CellSpecs = new[]
new CellSpec{ Sheet = "Sheet1", Column = "A", Row = 1 },
new CellSpec{ Sheet = "Sheet1", Column = "B", Row = 1 },
new CellSpec{ Sheet = "Sheet1", Column = "C", Row = 1 },
new CellSpec{ Sheet = "Sheet1", Column = "A", Row = 2 },
new CellSpec{ Sheet = "Sheet1", Column = "B", Row = 2 },
new CellSpec{ Sheet = "Sheet1", Column = "C", Row = 2 },
private static readonly uint NumCells = (uint)CellSpecs.Length;
private const string SPREADSHEET_ML_NS = "http://schemas.openxmlformats.org/spreadsheetml/2006/main";
private const string METADATA_TYPE_NAME = "MyMetaType";
private const string EXTENSION_URI = "http://example.com/extension";
public static void Main(string[] args)
if (args.Length != 1)
Console.Out.WriteLine("AddMetadata <doc.xslx>");
Console.Out.WriteLine(" Adds metadata to the specified document to demonstate some strange Excel behaviour");
Environment.Exit(1);
try
var doc = SpreadsheetDocument.Open(args[0], true);
StripMetadata(doc);
AddMetadata(doc);
AddMetadataType(doc);
AddFutureMetadata(doc);
AddMetadataRecords(doc);
AssociateCellsWithMetadata(doc);
doc.WorkbookPart.Workbook.Save();
doc.Close();
catch(Exception e)
Console.Out.WriteLine(e);
/// <summary>
/// Strip any existing metadata.
/// </summary>
/// <param name="doc">The document</param>
private static void StripMetadata(SpreadsheetDocument doc)
var wbPart = doc.WorkbookPart;
var cellMetadataPart = wbPart.GetPartsOfType<CellMetadataPart>().FirstOrDefault();
wbPart.DeletePart(cellMetadataPart);
/// <summary>
/// Add basic metadata part structure.
/// </summary>
/// <param name="doc">The document</param>
private static void AddMetadata(SpreadsheetDocument doc)
doc.WorkbookPart.AddNewPart<CellMetadataPart>();
doc.WorkbookPart.CellMetadataPart.Metadata = new Metadata { MetadataTypes = new MetadataTypes() };
/// <summary>
/// Add the metadata type used by all the metadata we're adding
/// </summary>
/// <param name="doc"></param>
private static void AddMetadataType(SpreadsheetDocument doc)
var metadata = doc.WorkbookPart.CellMetadataPart.Metadata;
var metadataType = new MetadataType
Name = METADATA_TYPE_NAME,
Assign = false,
CellMeta = false,
ClearContents = false,
ClearAll = false,
ClearComments = true,
ClearFormats = true,
Coerce = false,
Copy = true,
Delete = false,
Edit = true,
Merge = true,
MinSupportedVersion = 0U,
PasteAll = true,
PasteBorders = false,
PasteColWidths = false,
PasteComments = false,
PasteDataValidation = false,
PasteFormats = false,
PasteFormulas = false,
PasteNumberFormats = false,
PasteValues = true,
RowColumnShift = true,
SplitAll = false,
SplitFirst = false
metadata.MetadataTypes.AppendChild(metadataType);
/// <summary>
/// Add future metadata blocks which contain the actual metadata for each cell.
/// They are referenced by the metadata records.
/// </summary>
/// <param name="doc">The document</param>
private static void AddFutureMetadata(SpreadsheetDocument doc)
var metadata = doc.WorkbookPart.CellMetadataPart.Metadata;
var futureMetadata = metadata.AppendChild(new FutureMetadata());
futureMetadata.Name = METADATA_TYPE_NAME;
futureMetadata.Count = NumCells;
// Future metadata area
for (var i = 0; i < NumCells; i++)
// The metadata for each cell will be single FutureMetadataBlock containing an extension list with a single extension.
FutureMetadataBlock futureMetadataBlock = futureMetadata.AppendChild(new FutureMetadataBlock());
ExtensionList extLst = futureMetadataBlock.AppendChild(new ExtensionList());
Extension ext = extLst.AppendChild(new Extension());
ext.Uri = EXTENSION_URI;
ext.AddNamespaceDeclaration("x", SPREADSHEET_ML_NS);
ext.SetAttribute(new OpenXmlAttribute("value", ext.Uri, string.Format("test value {0}", i)));
/// <summary>
/// Add metadata records which point to each future metadata block.
/// They are in turn referenced by the cells.
/// </summary>
/// <param name="doc">The document</param>
private static void AddMetadataRecords(SpreadsheetDocument doc)
var metadata = doc.WorkbookPart.CellMetadataPart.Metadata;
// Value metadata area
ValueMetadata valueMetadata = metadata.AppendChild(new ValueMetadata());
for (uint i = 0; i < NumCells; i++)
// Type is 1-indexed, index into future metadata is 0-indexed
var metadataBlock = valueMetadata.AppendChild(new MetadataBlock());
var metadataRecord = metadataBlock.AppendChild(new MetadataRecord());
metadataRecord.Val = i;
metadataRecord.TypeIndex = (uint)1;
/// <summary>
/// Associate existing cells with existing metadata.
/// </summary>
/// <param name="doc">The document</param>
private static void AssociateCellsWithMetadata(SpreadsheetDocument doc)
for (uint i = 0; i < CellSpecs.Length; i++)
var cellSpec = CellSpecs[i];
var cell = GetCell(doc, cellSpec.Sheet, cellSpec.Column, cellSpec.Row);
if (cell == null)
throw new ArgumentException(string.Format("Cell {0} not found in row {1} of sheet {2}", cellSpec.Column, cellSpec.Row, cellSpec.Sheet));
cell.ValueMetaIndex = i;
/// <summary>
/// Get a cell given the document, sheet name, column name and row index.
/// </summary>
/// <param name="doc">The document</param>
/// <param name="sheetName">The sheet name</param>
/// <param name="columnName">The column name</param>
/// <param name="rowIndex">The row index</param>
/// <returns>The cell</returns>
private static Cell GetCell(SpreadsheetDocument doc, String sheetName, String columnName, uint rowIndex)
var row = GetRow(doc, sheetName, rowIndex);
if (row == null)
throw new ArgumentException(string.Format("Row '{0}' not found", rowIndex));
return row.Elements<Cell>().Where(c => c.CellReference.Value.StartsWith(columnName)).FirstOrDefault();
/// <summary>
/// Get a worksheet part by sheet name.
/// </summary>
/// <param name="document">The document</param>
/// <param name="name">The sheet name</param>
/// <returns>The worksheet part</returns>
private static WorksheetPart GetWorksheetPartByName(SpreadsheetDocument document, string name)
// Get Sheet by name from Sheets in Workbook
var sheet = document.WorkbookPart.Workbook.GetFirstChild<Sheets>().Elements<Sheet>().Where(x => x.Name == name).FirstOrDefault();
// Lookup WorksheetPart by Id
return sheet == null ? null : (WorksheetPart)document.WorkbookPart.GetPartById(sheet.Id.Value);
/// <summary>
/// Get a row given the document, sheet name and row index.
/// </summary>
/// <param name="doc">The document</param>
/// <param name="sheetName">The sheet name</param>
/// <param name="rowIndex">The row index</param>
/// <returns>The row</returns>
private static Row GetRow(SpreadsheetDocument doc, String sheetName, uint rowIndex)
var worksheetPart = GetWorksheetPartByName(doc, sheetName);
if (worksheetPart == null)
throw new ArgumentException(string.Format("Sheet '{0}' not found", sheetName));
return worksheetPart.Worksheet.GetFirstChild<SheetData>().Elements<Row>().Where(r => r.RowIndex == rowIndex).First();
struct CellSpec
public string Sheet;
public string Column;
public uint Row;

If you create a metadatatype with a single metdata block, and you reference that in your vm/cm cell attribute using a *one* based index, Excel seems to see the link and it honors it when saving the spreadsheet.
So, I ended up with something like:
<c ... cm="1"/> (I'm dealing with cell metadata, but the concept is equivalente to value metadata)
<metadataTypes count="1">
  <metadataType name="MyMetaType" .../>
</metadataTypes>
<futureMetadata count="1" name="MyMetaType">
  <bk>
    <extLst><ext
uri="http://example" xmlns:x="http://example"><x:val>87</x:val></ext></extLst>
  </bk>
</futureMetadata>
<cellMetadata count="1">
  <bk><rc
t="1" v="0"/></bk> 
</cellMetadata>
Hope this helps.

Open firmware startup disk by default

I have an iMac which by default always goes to the open firmware startup disk screen. How do I get rid of this? I have tried zapping the PRAM, reinstalling the OS and a different hard drive. There are no problems w/ the functionality of the computer or the software and there are no symptoms to say that there is anything wrong w/ the computer. Just want to get rid of having to hit enter at the firmware startup disk screen every time I turn it on. Any suggestions please.

Mark, it appears that the defauly startup mode has been changed on your Mac.
Probably the easiest way to get back to normal is using a utility. I use the free utility OnyX. In OnyX go to Parameters>Login and at the bottom of the pane you can change your Mac's default startup mode.

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