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View Full Version : 24-bit FastRAM oddities



AndyLandy
3rd December 2009, 20:37
There's a guy on ebay.de selling an A600 with an E-Matrix 68030 accelerator. (Won't link, since it's auction only -- search for Amiga 600 turbokarte) -- Thing is, the accelerator puts the 8MB FastRAM into the 24-bit address space, ruling out the PCMCIA port. Except that he's also using a 4MB PCMCIA RAM module. The Workbench title bar happily claims 12MB FastRAM, and SysInfo confirms that the E-Matrix is really using 24-bit addressing on the RAM. I guess it could be an elaborate hoax, but I doubt it. So, my question for our resident techies is:

WTF?

chiark
3rd December 2009, 20:54
I think it doesn't really put it in the 24 bit address space - if you look at it, the 8mb and 4mb space have overlapping address ranges.
It can also support up to 32MB, so that can't fit in the address space. Sysinfo could be wrong/outdated/confused.

The accelerator must know that the local memory is on its local map and not on the main amiga memory map... I guess they may be using the MMU - would be interesting to know if that's in use.

edit:
Actually, I think I'm talking rubbish. I was talking about the Apollo 630... The M-Tec seems a completely different beast!
The M-Tec 8MB apparently "wipes out" the PCMCIA port if you go on data on amiga.resource.cx, however according to bboah it is PCMCIA friendly...

It would appear odd if it maps memory onto the same area as shown in those screenshots... The MMU is not in use... Hmm...

Kin Hell
4th December 2009, 04:01
I've not had any experience of this Accelerator, but I've been reading about it & it is indeed PCMCIA friendly. Linky (http://www.amiga-hardware.com/showhardware.cgi?HARDID=92)

I'm only guessing PCMCIA is 16Bit & feel our beloved Zeets will have some usefull knowledge here. ;)

@ AndyLandy

Yeah m8, WTF??

@ Zetr0

Wazzon m8y?

Kin

Zetr0
4th December 2009, 11:01
hmmm it looks like I missed the auction on fleabay.de,

Although it is possible for it to be PCMCA friendly, the fact you have only a 16 bit accessible ram would cripple the CPU.

the Ram onboard is in Z2 24bit space BUT is 32bit accessable. I am curious on how they manage to get-over the reserved 4MB space for the PCMCIA thought.

Conflicting reports eitherway. they should just send it to me for testing....

with Alien Breed 92 SE, Tower Assualt, a little Sensi and a lot of Captive +D