What if PC ..... never existed?

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By PingPong

Prophet (3459)

PingPong's picture

14-11-2019, 06:27

Grauw wrote:

IMO for MSX2 the CPU upgrade was not needed yet, the VDP upgrade alone was major and justified the release. Only two years after MSX1 the CPU was still good enough. But for MSX2+ it was definitely due, especially since it was otherwise a lackluster upgrade that got poor reviews and didn’t offer much incentive for both users and manufacturers to invest in a new computer.

Panasonic made a half-assed attempt at it, but the BIOS didn’t support it and they didn’t fix the PSG clock either.

Msx was primarily aimed at games.
What does matter in this situation is a good video hardware. (good sprites, scroll support, fast bitter, no quirks or exotic limitations) and good sound hardware.
Even a 3.5 mhz z80 can do amazing things if supported by good hw as proved by some games that use v9990 and oplx chips

The power of computer is not only in the 16 bit cpu.
Look at the ti/99.16bit cpu but it is not more faster than msx1
Look at C64. With its underpowered cpu can do things that a msx2 cannot. Why? The Vic and the sid

By Parn

Champion (424)

Parn's picture

14-11-2019, 18:28

@gdx mentioned the Amiga and the Atari ST, but let's not forget about the Japanese scene, where MSX had to compete with NEC, Fujitsu and Sharp's own computer architectures. Compared to those, even in their 8-bit incarnations, MSX looks more playful, less serious. I think this ended up positioning the MSX against video game consoles with which it couldn't really compete.

And even the mighty IBM PC with anything less than a VGA card doesn't look good compared to even the puny MSX2. Of course it's very difficult to make a direct comparison, but Firehawk comes to mind. The MSX version looks and sounds better, IMHO.

By AxelStone

Prophet (2701)

AxelStone's picture

14-11-2019, 19:27

Grauw wrote:

This is exactly what the turboR does (specifically, the S1990 controller). The OCM and all 7 MHz upgrades that I know of do this incorrectly, resulting in bad cartridge compatibility in turbo modes. The Panasonic MSX2+ correctly provides the 3.58 MHz clock on the bus, and I suppose due to the modest increase in CPU speed the bus timings stay within tolerances (I don’t think it has a bus controller).

Mmm from my personal experience is just the opposite, turbo mode in Zemmix is clearly better implemented than MSX2+. First of all PSG remains working at 3,58Mhz, in Panasonic PSG clock is connected to CPU clock so in turbo mode the sound is buggy.

In the same way, the timming with the VDP is better. For example games like patched versions of Zanac-Ex and Space Manbow have graphic glitches in MSX2+ not present in Zemmix.

As I say, is my personal experience with both machines.

By Grauw

Ascended (8508)

Grauw's picture

14-11-2019, 21:14

I’m particularly referring to the external cartridge slot compatibility. The OCM / Zemmix Neo simply disregards any standard bus timing compatibility in turbo mode, so for example the SFG-05 turns into a glitchy mess of noise, and other sound cartridges have the wrong pitch.

For the PSG this is indeed a very annoying quirk of the Panasonic MSX2+ due to the internal PSG in the T9769 MSX-Engine being linked to the CPU clock rather than the 3.58 MHz one, even though it has a separate output for that. I consider it a bug in the MSX-Engine that the Panasonic engineers decided to leave in (hence my half-assed remark) rather than fixing the MSX-Engine or adding a discrete PSG. All signs point to them having put some effort in upgrading the MSX2+ CPU to 5.37 MHz and then giving up, I bet for time or cost reasons. There is a software workaround btw: multiply all periods by 1.5.

For the VDP, the Zemmix Neo does not have a real V9938 but a faster FPGA approximation of it, so it is not bound to its timing restrictions and can cheat compared to the original hardware. You will note that unlike a real VDP it’s not possible to access the VRAM too fast, so it doesn’t need to have waits at all.

By AxelStone

Prophet (2701)

AxelStone's picture

14-11-2019, 22:29

I agree, for me PSG issue is clearly a bug in Panasonic models. Even MSX1 has PSG conected to a independent clock, so I can't understand why in moderm MSX2+ Panasonic took this weird solution.

About Zemmix, for me is one of the best MSX models available because of I have the impression that have solved some problems and bugs of the original model: PSG one, VDP limitation, CPU at 8,06Mhz...is like having some kind of MSX2++.

By gdx

Prophet (3083)

gdx's picture

15-11-2019, 00:38

Grauw wrote:

For the VDP, the Zemmix Neo does not have a real V9938 but a faster FPGA approximation of it, so it is not bound to its timing restrictions and can cheat compared to the original hardware. You will note that unlike a real VDP it’s not possible to access the VRAM too fast, so it doesn’t need to have waits at all.

This is same like emulators and this is a problem for software developers. They make programs that seem to work, but they are not.

AxelStone wrote:

About Zemmix, for me is one of the best MSX models available because of I have the impression that have solved some problems and bugs of the original model: PSG one, VDP limitation, CPU at 8,06Mhz...is like having some kind of MSX2++.

The majority of these "problems and bugs" are not. It's just the OCMs hardware that is different and that acts differently. CPU at 8,06Mhz is a real good point though.

By AxelStone

Prophet (2701)

AxelStone's picture

15-11-2019, 15:59

gdx wrote:

The majority of these "problems and bugs" are not. It's just the OCMs hardware that is different and that acts differently. CPU at 8,06Mhz is a real good point though.

I know, I want to say that for me OCM / Zemmix is simply a new MSX model, and a very good one. In MSX we know there weree hundreds of different models with different manufacturers, Zemmix is simply one more launched in XXI century Smile

For me has tons of advantages: CPU at 8,06mhz, perfect VDP sync, PSG clock fixed, FM, dual SCC, SD card reader, VGA support...a very nice new model. It maintains the feeling of having a MSX, but with very good updated to feel you have a good revision.

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