Recent content by eharmon

Feels like OpenFirmware for 68k :D. It'd be real funny if someone ported OpenFirmware to run as a bootloader. I don't know if it would be good funny or bad funny but it would be funny.

It has two modes (or in later models, only the latter mode): operate the system over nubus (with a stub running on the main CPU to route bus requests), and operate as a second computer on a daughter card which can load resources from the main system. While the former mode is interesting from...

I've been curious (but not seen benchmarks) about how much slower a fast 060 with no FPU is versus an 040 with FPU. It's gotta be "much slower" but how much, specifically? On the one hand I feel like I'd stick with an LC. On the other hand I've spent $$$ on a PowerPC card so clearly I'm not...

The screen seems surprisingly bright for the era. Camera lying, or is it really that readable?

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...