Recent content by joevt

Service Source for the 7300 says the DIMMs must be 5V and that fast paged DIMMs also work. http://www.applerepairmanuals.com/the_manuals_are_in_here/PM7300_7500_7600_WS7350.pdf It says you can increase the memory to 512 MB. That would require eight 64 MB DIMMs. I'm pretty sure 128 MB DIMMs...

They all have different version numbers and therefore different 3 MiB checksums and different 4 MiB checksums. They all have different Open Firmware code. Rev A and Rev B are both 2.0f1 but Rev B has some updates. Rev C and Rev D are both 2.4 but Rev D has a small change. 077d.40f2.1 "Boot...

I had some more Serial Test Manager notes at https://tinkerdifferent.com/threads/new-diagnostic-tool.4593/post-39652

Does that apply to all 4 revisions of the Beige G3 firmware? Does that apply to Mac OS 9 as well? I've seen Mac OS 9 is able to see partitions beyond 128 GiB. I know that early versions of Open Firmware (e.g OF 2.4) have bugs related to detecting LBA28 and don't have code for LBA48. I think...

Was this image 2352/2048 times bigger than the partition created from disk2s1? If so, then it does contain all of the partitions. It's just in a different format than expected. Examine your disk images with this (replace path1 with paths of folders that contain disk images, separated by...

A CD has multiple "slices": diskutil list /dev/disk18 /dev/disk18 (internal, physical): #: TYPE NAME SIZE IDENTIFIER 0: CD_partition_scheme *755.4 MB disk18 1: Apple_partition_scheme ⁨⁩...

My serial cable notes at #10

Old World Power Macs have a Serial Test Manager (STM) On a Power Mac G3, it has a menu and prompt like this: > *************************************** * * * Serial Test Manager * * *...

The default boot-device is disk2:aix disk2 is a devalias for /bandit/53c825@11/sd@2,0 The default diag-device is cd fd:diags which I guess is a list of devices? I'm not sure how to interpret this because cd is not a devalias. It appears that cd is a special device that initiates a search for a...

Is it the first of these? 1987-03 - 97851DB6 - MacII (800k v1) 1987-12 - 9779D2C4 - MacII (800k v2)

My suggestion of creating an Open Firmware script to patch the firmware won't work if you can't boot into Open Firmware. Startup the B&W G3 with the programmer switch held down as if you were going to perform a firmware update (read the firmware updater instructions from Apple). Let go of the...

Apple II sound is 1-bit but it's not just a square wave. There's same oscilloscope captures in this video:

The firmware updaters from PowerLogix and Sonnet for G4 upgrades do not appear to be in the form of an Open Firmware script so they cannot be applied from Open Firmware. https://www.sonnettech.com/support/kb/kb.php?cat=317&expand=_a3&action=b153#b153 Apple's Firmware Updater (to upgrade to...

@startvec.>'excp stores the default exception handler which is _exception This does a throw of the exception vector number. Maybe it can be replaced by something that saves more info (copy all the registers and the stacks?). @startvec.>'syscatch stores the default catch handler which is...

I have a Trace for Open Firmware script that can show what's getting executed. It needs more work but can do some simple stuff. It works by patching every word or words that you explicitly ask to patch. Then when you enable tracing, it will output each word as it enters and exits, and displays...