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I wrote up a little guide to identify fakes via chip markings. It'll never help you catch everything but it might be helpful when browsing online since I've seen a lot of the blatant errors listed here: https://eharmon.net/retro/macintosh/identify-fake-68k/ Let me know if you're willing to share...

You'd be surprised. So much was still emulated on PowerPC, and it was "fast enough" that applications took awhile to transition. In the same vein, obviously running System 7 on a New World G4 will smoke any '060 anyway, but that's no fun (well it is fun, but differently fun). That said, I...

Some more info on async in DV26: https://wiki.preterhuman.net/DV_26_-_I_am_Curious_SCSI

Chapter 4 has some of this information, at least: https://wiki.preterhuman.net/Apple_A/UX_2.0_Toolbox:_Macintosh_ROM_Interface_030-0787-A

Some results from 4.3 today. As a reminder, I've got this in a Wombat board, which doesn't have native 4.3 support in ROM. So: You can't boot from drives attached to the SE IV. It doesn't seem to provide non-4.3 compatibility so presumably this requires a Quadra AV or PowerPC. Or at least it...

Great to have more hardware developers in the community! Overall I think you'll find the Mac ROM is much, much less auto-configurable (more like Kickstart 1.x than 2.x+). Using your memory example: ROMs are "universal", but only in theory. Despite many machines shipping with ROM SIMM slots...

FWIW, a driver can support both in a single binary, but it's basically two drivers in one. One old API, one new API. IIRC 4.3 drivers are always required to be backwards compatible (or at least, the documentation instructs you to). If you have an Apple_Driver43 partition, a 4.3-supporting...

I haven't timed it (someone else might have stats), but it's definitely noticeable. Not as much as the low latency from solid state, but it helps large programs load. SCSI is pretty complex. There's interactions between async bus communication, async drivers, and bus disconnect. I'll go first...

Yeah, I'm gonna try a Stage II. The docs claim they're wired for 20MHz operation, but I'll take a look at the board! Interesting. So maybe they really are faster, or maybe there's an interaction between the SE IV and a ZuluSCSI Blaster. There's a number of improvements in later machines that...

Interesting, so from those benchmarks, you can't really break the 10MB/s barrier on an 8100 either. I also noticed the same dip with a PowerPC card in the Quadra. The RP2040 Zulu is quite a bit faster than the SCSI2SD v6. I wonder if the card's read ahead cache makes up for lower transaction...

Continuing my SiliconExpress experimentation, I've been doing some benchmarks on my Quadra 650 board with ZuluSCSI. Read Native SCSI ZuluSCSI (RP2040)4,700KB/s SiliconExpress IV (8-bit) - 1.6.5 ZuluSCSI (RP2040)8,123KB/s SiliconExpress IV (16-bit) - 1.6.5 ZuluSCSI Wide 8,959KB/s Write...

With the right factory software, some CF cards can have their CHS values re-programmed, if you want an emulator-less experience. Unfortunately I've never had the right combo of card and software to try it myself, so I can't recommend a specific model.

Norton UnErase didn't find anything interesting on the disk image.

It seems like it's offsetting to 0x40800000 twice, even when I tell it to load at 0x0 manually. Loading it at 0x100000000 (overflowing it back to zero) works though, amusingly. add-symbol-file Quadra800ROM.elf 0x100000000

This is great! I was giving this a try today and newer gdb doesn't seem to like it...am I just doing it wrong? The target architecture is set to "m68k". ⚠️ warning: BFD: warning: Quadra800ROM.elf has a section extending past end of file Reading symbols from Quadra800ROM.elf... ⚠️ warning...

It's very low level and pretty difficult to use. That's exactly why I was interested in it (well, that and I'd really like to find out what's wrong with my on-board ethernet and the SONIC self-tests should help). I wanted to replicate this with QEMU for easier local experimentation and it turns...

Welp, I still haven't gotten the overrides to enter diagnostic mode to work quite right...scratching my head still. But I can tell you how to get into serial diagnostics on newer machines with no fuss, tested on my Wombat: Put a moderate amount of RAM in the system so the memory check takes at...

That should be PRAM at offset 0078 OR 00F8 set to "SCBI" (0x53434249). If I reboot with this set the machine resets its PRAM, so it appears to be taking the correct code path. Setting it to something like 0x11111111 it just ignores. So I took the external SCSI connector and jumped: 2 -> 14 3...

Okay, made some progress reverse engineering from these clues and the 53c96 data sheet.. I haven't tried this on a real machine yet, but I believe for machines without an edge connector, the following should work, approximately: Connect a serial cable and configure 19200 baud. PRAM at 007800F8...

Interesting, so my hunch PA0 had been relabeled as TEST was incorrect...it's not connected at all. So for Wombat the implication is the test can only run if you have an SCC (Wombat should pass that), set a specific PRAM value, and bridge some SCSI pins? Or was the PRAM value a red herring and...