Mapper Megaram 512kb Belavenuto

By nico24

Supporter (3)

nico24's picture

28-10-2017, 22:05

Hi,
I purchased a Mapper Megaram 512kb from Ebay. I own the Panasonic A1-Mkii, although I am using an improvised power supply. The MSX itself works just fine. However when I plug the Megaram into the unit I can get it to recognize it, but it never boots into a DOS environment (Nextor I assume). I can get it to boot into Nextor Basic, but from there can seem to do anything useful.

Is there anyone out there that can guide me? Is my MSX not really capable or maybe the Basic environment is okay to do what I need to do given more commands. I don't think it is recognizing any extra ram though.

Anyway - many thanks in advance.

Nick.

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By gdx

Prophet (3037)

gdx's picture

29-10-2017, 12:06

Do you have the SD Mapper & Megaram 512Kb Expansion interface?
Is the switch well placed on Memory Mapper mode?

By Pentarou

Master (223)

Pentarou's picture

29-10-2017, 13:48

nico24 wrote:

it never boots into a DOS environment (Nextor I assume).

Do you have an SD Card with the correct Nextor/DOS2 files?

nico24 wrote:

I don't think it is recognizing any extra ram though.

You are saying that because the initial blue boot screen doesn't show the RAM or have you done some tests?
Set the switch correctly and use a memory test.

By NYYRIKKI

Enlighted (5384)

NYYRIKKI's picture

29-10-2017, 13:58

Yes, good to notice that MegaRAM <> memory mapper. MegaRAM can't be used to run DOS2 or Nextor, but if it can be configured to emulate memory mapper then it should work fine as long as you have DOS2/Nextor ROM in some other slot.

By nico24

Supporter (3)

nico24's picture

29-10-2017, 16:01

OK - so i worked out (probably should have known) that the 2GB card is the limit. I had switched it out for an 8GB version. So when I switched the 2GB back it works fine.

So now my issue is that I can load the low size ROMs up to 32k but not the megaroms or anything above 32k. Is there anything specific I should be doing with the megaram? I don't know what a megaram interface is - is that specific hardware? The system is using SofaRun to load the software.

I'm really novice on this subject sorry. The 512K - is it an assumed system requirement - or is it able to apply 512k memory?

By l_oliveira

Hero (526)

l_oliveira's picture

29-10-2017, 17:40

To be able to use the megaram function to load megaroms you need to install a memory mapper cartridge on the MSX.

The reason being that MSX DOS2 (Nextor is an enhanced DOS2 rebuilt from source code) requires at least 128KB of memory mapper connected to the system to boot and your MSX2 machine only have 64KB of normal RAM. If you select MEGARAM mode you lose NEXTOR (it will quit booting) and you will end with no access to the SD card because NEXTOR is required for that. Unfortunately the MEGARAM feature is only usable on computers which have a built in memory mapper or the user have another memory mapper connected. That's why they added a switch to the cartridge so you can select mapper or megaram. Unfortunately it can't be both memory types at the same time.

By NYYRIKKI

Enlighted (5384)

NYYRIKKI's picture

29-10-2017, 17:42

MegaRAM is a device that assigns the memory in the cartridge in a way it looks like MegaROM to the computer. Memory mapper is another way of assign memory that is defined in MSX2 standard. These two methods are different from each other and not compatible. Memory mapper is meant for expanding the usable RAM for application while MegaRAM is used to play cracked MegaROM games. The 512K in the name refers to the size of RAM in the device. (512KB)

If you have some memory cards involved then this might be some combination cartridge that has some other features as well build in to same case. (In this case the cartridge includes slot expander as well and it can't be placed in to a already expanded slot on MSX.)

By l_oliveira

Hero (526)

l_oliveira's picture

29-10-2017, 17:52

As per NYYRIKKI's suggestion, having a MMM (Musical Memory Mapper) cartridge connected to slot 2 would enable you to use the SD in MegaRAM mode for loading MegaROM games.

By nico24

Supporter (3)

nico24's picture

29-10-2017, 19:17

OK - so I don't totally understand the above info at the moment - I'll try and work through it. I did update the SofaRun to the latest and it seems to work just fine to load the Megaroms. so for now I'm happy.