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interesting levco upgrade for the se


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may 1987 issue of macuser had this ad (and a few months afterward too) if anyone might be curious about its existence back then

 

I don't know a lot about 68k cpu technicals but I wonder how close a levco-upgraded se would had been to a se/30 tho?

macuser_may1987_levco.jpg

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I have one of these from an SE I picked up a few years ago but seldom use. It throws up a nice Prodigy banner during boot. I haven’t tinkered with it or run benchmarks but I do know it does not have an FPU installed. 
 

One question i have might be, if it has an 020 and MMU, is it essentially a Macintosh II, thus could be seen as such by A/UX?

 

I recall having to remove RAM on the SE logic board in lieu of the Prodigy’s RAM. Also I remember it fit kind of weird but I never really use that SE and would consider trading it away…

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Eh... 70% of the way? Perhaps 80%?

 

The 68030 had better caches, and a few optimizations to the core that the '020 did not have. Also, the underlying SE motherboard only had a 16 bit data path - depending on how the Levco board is constructed, that may or may not result in some performance bottlenecks compared to the 68030's full 32 bit bus.

 

I suspect - without proof, not having one in my possession - that the A/UX installer will check with the Gestalt Manager for the machine type; and go with whatever the ROM says it is. Someone enterprising with a hex editor could patch that if necessary.

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4 hours ago, bdurbrow said:

Someone enterprising with a hex editor could patch that if necessary.

 

The problem here is that you're likely to end up in the same situation as you do if you force it to install on other unsupported machines: the kernel may start, but there won't be drivers for the peripherals (especially video), so you won't actually be able to use it.

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I know zero about A/UX but find this interesting as it’s not obvious why this would be true:  it requires video drivers of some sort?  (Could one provide them in software?)

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Posted (edited)
28 minutes ago, Crutch said:

I know zero about A/UX but find this interesting as it’s not obvious why this would be true:  it requires video drivers of some sort?  (Could one provide them in software?)

 

Yup, this is why it won't run on an LC475, despite it in theory having all the hardware A/UX needs: or rather, it will run, but there's no video at all, which puts one at a bit of a loss.  When control is handed over to A/UX it starts using its own drivers for basically everything, not unlike a modern UNIX-like would.  In theory, I don't think there's anything stopping anyone writing drivers to make it work on unsupported machines, but I'm not sure anyone knows how to.  It'd be a really fun reverse-engineering project for anyone who really knows that vintage of UNIX, I suspect (I don't)

Edited by cheesestraws
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Hmm... I'm mostly guessing, but... I suspect that the driver for a Mac II with the dumb-framebuffer card running in 1-bit mode would be hackable into thinking it's a 512x384 framebuffer at the fixed address that the SE/30 has... or at least, I think it has. I'd have to check my documentation to be sure. Otherwise, you'd have to find where the system stuck it.

 

I have no idea if there's something else in the system that would choke on a framebuffer smaller than 640x480, though...

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Posted (edited)

You can put any resolution you want into the declaration ROM and the Mac will just address that.

The actual output resolution isn't going to change though but instead you will get a 512x384 window inside a 640x480 screen output.

 

To change the actual address range of the framebuffer in the cards address space you would have to change more than just driver code.

 

Edited by Bolle
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Um... I was referring to changing the address that the A/UX video driver was looking for; assuming that it was hard-coded... not changing what hardware or firmware was doing.

 

Come to think of it, if the SE/30 has a standard Slot Manager declaration for it's internal display, and A/UX supports arbitrary video cards; then it may just work out-of-the-box. Dunno???

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