FS-A1ST vs FS-A1GT vs MSX2+ (Advice Needed)

This is all very interesting
So is it pointless getting the extra 512kb, or not?

You do not need to keep a key pressed to activate the extra RAM on turboR. That’s just false.

The question is really, what do you need the extra RAM for.

For MSX computers with less than 128K, you need it for DOS2 support, which is the primary reason to have RAM built into the SD interfaces with DOS2. ASCII’s original DOS2 cartridge also had extra RAM for that reason. So if you ever might be using it with an earlier generation MSX, then it will be good to have the 512K memory. For this reason I recommend getting the MFR with 512K option.

There is very few software which needs more than 128K though, and the turboR has either 256K or 512K, so in principle that’s plenty for most things.

Now about software which does want more than 128K, one category of those is game cracks, which are made useless by the MegaFlashROM. Of the remaining software, well behaved DOS2 software is able to access all the memory. One example of memory-hungry software is VGMPlay, to play music files. VGMPlay will use all available memory just fine.

Not all DOS2 software with high memory requirements is well behaved though, which is where the “4” key comes into play. Nextor contains a little hack for the turboR where if this key is pressed on boot-up, the largest memory is selected as the primary memory. This is how it used to work on previous MSX generations, but on the turboR the internal memory is much faster, so it always picks that first.

@Meits I wonder why you do keep harping on about that particular detail... What memory hungry software are you using on that has issues with secondary mappers? I only had to use the 4-key once in the past four years. I think it’s a fairly theoretical issue. As said, the real question is, what do you need extra RAM for in the first place on the turboR. There are uses for it such as VGMPlay, but not everybody will be going to use that.

I think you’re misunderstanding a bit. I don’t do any searching, DOS2 has already found it for me. Software only needs to store the mapper segment and slot number when requesting memory, and select the slot when switching mapper segments. It’s extremely low-effort.

Software which is not well-behaving and only supports the primary mapper explicitly tells DOS2 to only return memory segments from the primary mapper, and ignores the slot number. In other words, they do not support it on purpose, for no real reason. That’s fine if you use less than 256K, but if you use more then you’re excluding turboR ST and/or GT users, and IMO that’s not OK.

It’s only an issue if the software does the wrong thing. And software has good motivation to do the right thing: turboR support. So I don’t think there is many software which has this problem, or that a software developer would reject a bug report if it did (like RoboIMF was fixed recently).

Anyway, my point was that it’s an uncommon issue, so shouldn’t factor into the decision. If you feel like you would do more than playing games only, and use software that needs more than the system’s built-in amount of memory, regardless of the MSX version, then getting the 512K option is a good idea.

Thanks very much for clearing that up, Grauw.

As long as it's not useless, I'll probably get the 512k just for the hell of it. I can't really imagine what I'd use the system for apart from games, but who knows.