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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: on December 19, 2002, 06:54:46 AM
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I have an 1230 accelerator for my Amiga 1200. ( A friend let me borrow it until my PPC accellerator arrives :) )
I noticed that it has a slot for an MMU unit.
Does MMU stand for Memory managment Unit?
What does it do and is it going to make my Amiga faster if I install one?
Thanks in advance.
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Yes, the MMU is the memory management unit, however this is usually built in the processor. 68030, vs the 68EC030.
Are you sure the socket isn't for the 68881 FPU (Floating Point Math Unit?)
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Well, it also has a slot for an FPU and its taken by the 68882.
I notice that the the accelerators cpu is a MC68030FE2, if that means anything.
The model of the accelerator is MTec T1230/28
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MC68030 should be a genuine Motorola "full version" '030, which means it would already have an MMU built in.
(I can't find any references to an FE2 designation, but I'd imagine it is just a manufacturing code)
So, you should already have an MMU... Now, if the MMU is enabled by default or not on your configuration, that is another question. A program like SysInfo or some other benchmark util should help here.
...And if you already have an FPU socket with a 68882, I'm fresh out of ideas on what that other socket would be for... How many pins does it have? What style socket is it? (I haven't seen an MTec board.)
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MMU (memory management unit) is a wicked little things that allows the CPU to have its Memory functions controlled by an external prossesor. This allows for things like Memory protections, and flawless integration of Virtual Memory. As well as superiour cache management.
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Also,
To anybody that has the same accelerator :
I am looking at the dip switches on the accelerator and I noticed one that has the words "turbo" next to it.
What will that do if I set it on ?
(I have this fascination with all things named turbo, super or phat)
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I thought that all AOS pre 4.0 dont have Virtual mem.
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Its this accelerator :
http://www.amiga-hardware.com/mtec1230rtc.html
In the pic, the MMU goes in the only empty slot on the board.
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I thought that all AOS pre 4.0 dont have Virtual mem.
True by default, however there are some (mostly ineffective) ways to add it to earlier Amigas that have MMU functions. The MMU does not need to be (and, in fact, usually isn't) external to the processor, but maybe that socket is for adding an external MMU to a 68EC030 processor. Your MC68030 shouldn't need one, though, as it would have MMU functions built in the chip.
The MMU features will also let you use some more advanced features in emulators. Outside of that, though, it's of little performance gain.
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In the pic, the MMU goes in the only empty slot on the board.
Hmm... After looking at the picture and description, I ask again, are you sure? I think that is a PGA socket, and can be used instead of the FPGA to house a math-coprocessor (FPU). (two different kinds of sockets, but both do the same thing, so only one needs to be in use)
Plus, as the description says, the model pictured featured an internal (on-chip) MMU. Since your model does not have an EC030, it has a full MC68030, you should also have the internal MMU functions, already.
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Thanks for all the info.
This place is great! Its my second post and again I get an instant response to my questions.
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Ilwrath,
I'm pretty sure. Thats what its written at the top of the socket.
Maybe its deactivated automaticaly because I have the 68030 proc.
Perhaps it was more cost effective for this company, to just leave the socket in when they manufactured the board. No clue!
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the socket was put there to make sure users wern't stuck with the
wrong fpu if they were buying one later on instead of with the
board.
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by the way, try running showconfig in tools, that should tell you if
you have an MMU or not.
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Looks very similer to the "Viper" series of accelerators.
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the socket was put there to make sure users wern't stuck with the wrong fpu if they were buying one later on instead of with the board.
Yep.... I tend to agree, based on what I've seen on other 68030 cards.
I think the MMU label on that socket is a mislabel. (It happens.... more often than you'd think!)
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Rob wrote:
by the way, try running showconfig in tools, that should tell you if
you have an MMU or not.
That doesn't matter.
Most EC030's have a more or less faulty MMU that show up in showconfig. ( certain series of this CPU apparently had a functional MMU aswell. They were just standard 030's relabeled as there was a higher demand for EC030's at the time )
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If you do have an MMU, Thomas Richter's MMU library is worth
looking at .
The Sinclar ZX Spectrum emulator ASP uses it to emulate the memory
bank switching features of the later 128K models. Something not
possible with other Spectrum emulators for the Amiga.
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Hmm... I had one of those MTec 1230-cards. It has one socket for
PGA-fpu (68882) AND also a socket for PLCC-fpu (68881). But you
can´t use both at the same time... :)
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So its probably a mislabeled 68881 socket then.
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The MMU features will also let you use some more advanced features in emulators. Outside of that, though, it's of little performance gain.
An MMU is required if you want Linux. Maybe there's some kernels that doesn't require it, but the ones Iv'e seen require one.
And, don't know if it's stated elsewhere, but the MMU basically just takes care of addressing addresses to other addresses. Instead of doing it in software. Atleast that's what I've been told.
So a patch to the syscall AllocMem would introduce VMM to AOS... I think, basically? :-?