DosFox

“If a thing is worth doing. It’s worth doing badly” To get a Macintosh ii system to boot, it needs an Apple Sound Chip (ASC). HOWEVER. If you replace the ASC with an octal buffer and eight pull down resistors to provide 0x00 onto the bus, it’ll boot. This means you only need a single IC from a Macintosh ii system to make a booting system - that being the GLUE

Continuing on with the OSHintosh IIxi malarkey. So there is a pretty neat modern app that implements the techstep diagnostic serial commands. It’s called reconnaissance, and you need an RS232 to appletalk cable for it to run: https://recon-68k.github.io/

I think I just found a 40 year old Easter egg. I was looking into the Levco Monster Mac, which is an upgrade board for the original Macintosh 128k/512k which adds up to 2mb of ram as well as SCSI. An interesting feature is that this upgrade doesn't necessarily require Macintosh plus ROMs to work (most expansion cards do, as the original ROMs only work with 512k of ram, and don't have SCSI support). Fortunately the ROMs for the Levco Monster Mac have been dumped. https://archive.org/details/levco-monstermac-2mxs-rev-d-proms_202505 I reassembled the ROM from the high and low ROM dumps, looked at the resulting binary with a hex editor and there's a nice little greeting for people poking around the ROM 😂

Oh god. I’ve somehow nerd sniped myself into investigating whether building a powerpc PPC 601 homebrew computer is even feasible.

🥳

And yes, with shapeshifter it can act like a shitty Macintosh ii!

For context: https://www.folklore.org/Evolution_of_a_classic.html I've also confirmed that yes, it is present in MacPaint 2.0 from December 1987. The later 1988 version appears to have removed the Easter egg

Also I really should start ordering more black PCBs - this is my take on the nanomig Amiga FPGA board, which includes a serial port and ADB converter. Look how swish it looks!

I'm considering making this an SE footprint (or maybe a Plus footprint! That could be fun), or an ATX ish PCB. It'll probably be used as a test bed for creating implementations of those two ICs. Or at least replacements that work just well enough to get the thing to boot.

24,000 steps. Whoooo.

My current thinking is that the ASC could be replaced with literally a buffer, some glue logic and a 555 timer - though a dual ported 4K SRAM and a Pico may make for a more functional ASC replacement. The GLUE.... Is going to be trickier

@snowfox@tech.lgbt I mean, the GLUE can be broken down quite nearly into several functions. If you tackle each one as an independent module, it wouldn't be completely outside the realm of possibility to figure out how to make a work-alike solution. That, or down enough monster so that you can perceive the fifth dimension, and use the very nice silicon shots, degate, and the VLSI manual to figure out a 1:1 functional replica

There are currently two ICs that will need to be sourced - namely the Apple Sound Chip (ASC), as well as the GLUE.

@6a62 boards were made by apple ;p

@_the_cloud@mastodon.social LocalTalk also worked on the IIe with the workstation card!

@JetForMe@geekstodon.com I still need to complete the PCB fixes!

@cccpresser oh huh, so they're basically 22V10 shaped CPLDs? Cute!

@colinstu @6a62 as far as I'm aware, the TNT and Tanzania boards were from apple. Or at the very least, used apple parts

@Geekman that technically doesn't count as it's emulation rather than actually running on the bare metal 😅

@aidan solid blobject

@aidan oh god same!

@hkz@social.chinwag.org damnit I even double checked what I sent 😅 I meant the '21 Know that feeling 😬

@hkz@social.chinwag.org ah! Did the 74LS10 and 74LS21 combination work?

@colinstu it's cleaning up alright, but I'm pretty concerned that theres a lot of dead vias, as well as a good chance of dead chips as well It's going to be a long, long project

@aidan I'm not sure if that's CHRP 😅

@jamesb@fedi.duckduckpigeon.co.uk shopping centres mayhaps?

@jamesb@fedi.duckduckpigeon.co.uk bold of you to assume I would knowingly set foot into a spoons

@me_@sueden.social ahhh, now the interesting thing is that there's a dump of ROMs of another variant of the monsterMac that doesn't include SCSI. The ROMs are identical! This begs the question - does this ROM only fix the RAM limitation, or does it actually include a SCSI driver?

@littlemisssynth Mac on Linux still doesn't count in my mind ;) But as far as I'm aware, Mac OS can load without a video adapter. The graphics driver should be able to initialise the card once you're in the desktop

@bakkus oh!! I did not know Bolle redid the schematics as well

@jamesb@fedi.duckduckpigeon.co.uk at 10pm it'll be whatever bar you just came from

@littlemisssynth hm, I wonder if a modded GPU would be necessary - perhaps Mac flashed PCI card could work?

@bakkus@bitbang.social oh yes!. Soon!

@isonno@mastodon.social woah you worked on Scorpius? That's brilliant!

@whitequark may the cube be with you

@bakkus@bitbang.social I think I need to make sure the OSHintosh actually works first 😅😅

@bakkus@bitbang.social not a bad idea to be honest, although my approach to design is quite cautious - sort of only doing one change at a time. I'll have to play around with 72 pin SIMMs with one of my clones to understand how they work

@bakkus ah yes the bomarc ones. Still a bit worried that I won't be able to repair it 😬😅

@Geekman CHRP has allowed system 6.0.8 to run on PowerPC hardware. The problem is it's still running on a Mac, and WiiMac only targets Mac OS X