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Once PBX has mapped it, yes, e.g. bank 6 could be mapped to 64MB to 79MB, but that 16MB would just wrap around to 0. When checking RAM earlier, each Bank 1..7 can be mapped to the 16MB to 31MB region so they can be checked individually. Pretty good! I don't know why PBX works the way it does...

The PBX chip, which manages the physical to physical mapping, is on the Motherboard. So, if the Ram is plugged in the normal way, which I think it must be, then the limit must still be 64MB. To repeat. PBX is a 32-entry array of nibbles; one entry per 2MB of physical memory the motherboard can...

The way it works is that the serial port can be driven by an external clock. So, if the clock is at, e.g. 1MHz and you select 1MHz, then the SCC does a ÷32 to get 31250. But I think, also the MIDI Patchbay control panel sets it accordingly. I have used my Mac Plus with my MIDIMAN: I think you...

Excellent! Oh, you're using BBEdit. Didn't know you've never used a proper Mac Portable! I've had a very short go on one back in the early 1990s (or maybe just shortly before the PB100 came out) when someone brought one into the Nottingham Microcomputer Club. It was a big, heavy dude! Also, as...

This is truly astounding. An article about the various control panel designs of Macs during from System 1.0. However, the demonstrations of the Macs are emulations run via Infinite Mac (you can embed emulations from there in other websites now, well done @mihai !! ). What's even more amazing is...

Well, it's an interesting feature to explore. Let's say we're in the Classic Mac OS era (7.x to 9.x) and we want to implement this feature. I think the neatest method is a RHS menu bar option (what's that called in Classic Mac OS?) with an icon. Maybe it should look like a drive, but the...

The question is still fairly confusing. You don't want it unmounted, you just want to be able to "Hide" the volume like you can with an application. So, if this is possible [looks like it isn't], then it's possible to write a small app/ extension or Control Panel which allows you to select a...

I didn't know that, but if it's the case, then I guess it's because it only has a 68020. But that can be fixed by adding the MMU, right? I may still have it at my Dad's house somewhere. We thought it was special. The layout of the labs was: ----+----------+---------------+----------+--- ...

I guess many people on the 68KMLA haven't even used the Mac II. I first heard about it through Personal Computer World (UK) in April 1987: The artist took a ray-traced image and extended it to the edges of the magazine. Then PCW also packed an A2-sized poster (folded 4x) in the magazine with...

It's amazing how one encounters cognitive hurdles (mostly abstractions) when learning new languages. First computer (aged 12-13, 1980-1981): ZX80. Personal Computer World listed a ZX80 "Duck Shoot" reaction game, which contained some machine code to pause the screen until a key was pressed. On...

Can anyone help me here? I wanted to play around with a bit of Swift and SwiftUI (because that's what Apple are promoting). I've read quite a bit in the documentation and watched a few videos, but frankly there's something I'm not getting about declarative UIs. Here's some code that illustrates...

LOL! I like AARCH32 assembly as well as Thumb, but my favourite still has to be Motorola 68000 (though I quite like MSP430 for the simplicity). All of these trace their ancestry back to the 6502, 6800 which in turn derive from the pdp-8 and pdp-11; which may also be inspired by the MIT...

That sounds amazing, like the inverse concept of the on-disk New World ROM with OF chip-ROM!! I guess it'll work on my PB1400c? I've done a lot of Z80, 68000, 8086, ARM(Cortex) assembly and PPC asm scares me too! The real problem for me is that the mnemonics are all a bit mad: random lengths...

I didn't know that. I knew that there were debates in the Houses of Parliament after the TV show "The Mighty Micro" was aired, on ITV (at the time, only 3 TV channels in the UK). https://en.wikipedia.org/wiki/BBC_Micro#History Although the UK never had minitel, there are probably a few more...

So, just to recap (sic). If I get 250ml of IPA from trade-chem.co.uk for £5.99 I can use a microfibre cloth (from a spec-saver's glasses case) to clean it? https://trade-chem.co.uk/liquids/isopropanol-alcohol-printer-cleaner/ Is it OK to use cotton-buds instead, or is there too much of a...

Great, I've just read it in French and understood it all! Fantastic sleuthing! I realise you've not yet managed to trigger the Easter egg, so it still remains as an image within PowerPC Enabler 1.1. It's really great to get a bit practice in French!

Part of the fun of this thread is finding the quirks in the 603 and P5200 specs. The 32-bit/64-bit hardware bus select is a good reminder though. Good point, it was a 68030-style PDS. It's OK, I've misunderstood a few things here - at least once I've gone back & repeated a previous...

Can you actually run System 1.0 to 7.5.3 on a 68010? Some instructions are privileged, like MOVE SR,dn; whereas they're not on the 68000. OTOH, the Mac's 68000 was always in Supervisor mode.

Hmm, but now I'm thinking it's quite hard to get standard bench tests onto it, so .. maybe not!

SpecInt92 and SpecFP92 (as well as Spec89) were measured against the VAX 11/780 which was defined to have a performance of 1 MIP (though in fact it was less than that). And for those not familiar, the VAX 11/780 was an early 32-bit Super-minicomputer developed at the end of the 1970s, around the...