PRAM contents.

Paul Grayson wrote on :

Is there a definitive list available anywhere that goes into detail as to exactly what is stored in PRAM?

I've just zapped mine and it appears to have resolved a serious performance problem on this iBook, which I suspected was due to the hard drive being accessed using PIO instead of UDMA. To double check this, a detailed list of all the parameters set in PRAM would help.

leeg replied on :

Paul Grayson wrote:

Is there a definitive list available anywhere that goes into detail as to exactly what is stored in PRAM?

I've just zapped mine and it appears to have resolved a serious performance problem on this iBook, which I suspected was due to the hard drive being accessed using PIO instead of UDMA. To double check this, a detailed list of all the parameters set in PRAM would help. A reasonable list of what's in the NVRAM may be discovered by the 'print-env' word at the OK prompt. However Apple don't document too much of the PRAM's contents, and indeed tell us not to rely on anything we discover by reverse engineering being available. So exactly what is stored in one machine may or may not have anything to do with exactly what is stored in another :-/

Paul Grayson replied on :

On Mon, 03 May 2004 12:52:05 +0100, leeg wrote:

A reasonable list of what's in the NVRAM may be discovered by the 'print-env' word at the OK prompt. However Apple don't document too much of the PRAM's contents, and indeed tell us not to rely on anything we discover by reverse engineering being available. So exactly what is stored in one machine may or may not have anything to do with exactly what is stored in another :-/

Running 'printenv' from OpenFirmware doesn't offer any real clues.

My problem may have started after playing with a Linux bootable CD distribution, so I'm wondering if that does odd things with the PRAM? I'll have to download the Linux kernel source to find out. That could take some time.

leeg replied on :

Paul Grayson wrote:

On Mon, 03 May 2004 12:52:05 +0100, leeg wrote:

A reasonable list of what's in the NVRAM may be discovered by the 'print-env' word at the OK prompt. However Apple don't document too much of the PRAM's contents, and indeed tell us not to rely on anything we discover by reverse engineering being available. So exactly what is stored in one machine may or may not have anything to do with exactly what is stored in another :-/

Running 'printenv' from OpenFirmware doesn't offer any real clues.

No, as I said, this stuff isn't well documented and I don't think that Apple have plans to change that. Indeed even their implementation of OF is severely lacking in help [though there are a couple of technotes, they're bobbins].

My problem may have started after playing with a Linux bootable CD distribution, so I'm wondering if that does odd things with the PRAM? I'll have to download the Linux kernel source to find out. That could take some time.

Ah, is there not a CVSweb interface? There used to be one at lksr.org but it seems to have disappeared :-(.

zoara replied on :

Paul Grayson paul@redacted.invalid wrote:

Is there a definitive list available anywhere that goes into detail as to exactly what is stored in PRAM?

RATTLE, in most (but not all) cases.

    -z-
Andrew Collier replied on :

In article c758ec$hjk$1@redacted.invalid, leeg leeg@redacted.invalid wrote:

A reasonable list of what's in the NVRAM may be discovered by the 'print-env' word at the OK prompt.

Typing:

nvram -p

at the terminal is probably more convenient, as you don't need to reboot, and you can copy and paste the interesting bits into google.

Andrew

Paul Grayson replied on :

On Mon, 03 May 2004 15:07:18 +0100, leeg wrote:

Ah, is there not a CVSweb interface? There used to be one at lksr.org but it seems to have disappeared :-(.

You can't grep multiple files through such an interface, though.

Anyway I've downloaded 2.6.5 now, but it's going to take a while for me to find anything relevant. I'll probably need to get a version of 2.4 later as that's more likely to be the kernel on that CD.

Paul Grayson replied on :

On Mon, 03 May 2004 14:02:32 +0100, Paul Grayson wrote:

My problem may have started after playing with a Linux bootable CD distribution, so I'm wondering if that does odd things with the PRAM? I'll have to download the Linux kernel source to find out. That could take some time.

No, it's not that. They've come back again. They seem to happen after leaving the machine running for a long time, but not sleeping. Then the severe problems return. The only thing I can consider is the hard drive spin down. I'll turn that off, zap the pram yet again, and observe for a few days.