What if V9938 never existed?

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By PingPong

Prophet (3448)

PingPong's picture

18-05-2019, 18:48

Following the what if tendence i post also my question.
Let's imagine that msx2 have used from the beginning a V9958 instead of V9938.
Do you think that this could have been changed the destiny of MSX in a sensible way ?
I mean for example the availability of games or interest in msx before users moved to other system?

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By erpirao

Paladin (944)

erpirao's picture

18-05-2019, 19:16

even with the limitations of 9958, if it had left in 1985 instead of 9938, it would have meant a huge change of scene.
even if the yjk (sc12) had been removed, and the sc8 had been converted into (256x212x64colors of the palette) we would have already had a system that, in 1985 would have an omnidirectional scroll, in BITMAP mode.
even with the system of sprites so strange, that scroll would have been a revolution in the computer scene.
Anyway, I think that another improvement that could have changed the 9938 is that if the sc4 instead of 2 colors for every 8 px per pattern, it would have had a mode like that of the nes, that is 4 colors (3 + 1) colors per 8 px, it would also have been a very important change.

By Manuel

Ascended (15752)

Manuel's picture

18-05-2019, 22:24

I think it would have made a much bigger impact if the MSX1 would have had the V9938...

By DanySoft

Champion (433)

DanySoft's picture

18-05-2019, 22:43

erpirao wrote:

even with the limitations of 9958, if it had left in 1985 instead of 9938, it would have meant a huge change of scene.
even if the yjk (sc12) had been removed, and the sc8 had been converted into (256x212x64colors of the palette) we would have already had a system that, in 1985 would have an omnidirectional scroll, in BITMAP mode.
even with the system of sprites so strange, that scroll would have been a revolution in the computer scene.
Anyway, I think that another improvement that could have changed the 9938 is that if the sc4 instead of 2 colors for every 8 px per pattern, it would have had a mode like that of the nes, that is 4 colors (3 + 1) colors per 8 px, it would also have been a very important change.

Unfortunately both in v9958 and v9938, the table of sprite visible on the screen is always the number 32 as maximum!
Therefore I don't find anything important with the "clone" sprites of tms9928a, v9938, v9958 ....
Bye bye
DanySoft

By PingPong

Prophet (3448)

PingPong's picture

19-05-2019, 12:38

Umh, it does depend. if v9938 had to be the msx1 vdp, i expect that TMS compatibility was not there.

An MSX1 with a dedicated VDP chip could have been
- 32KB of VRAM
- a Screen 0 mode with decent color support (8x8x2 colors)
- a Simple gfx mode like 256x192@16 color no-colourclash tilemapped mode providing more good sprite support

This could have been some interesting effects:
- Clear architecture
- Probably better sprite support
- Probably better I/O support
- Better konami games
- Less games in total since some speccy ports could have been done with greater effort and this has others effects:
- limit the number of zx ports
- increase the quality of zx ports
(look at the CPC)

By Juan Luis

Resident (46)

Juan Luis's picture

22-05-2019, 22:45

There were several limitations in MSX standard from the start. These are:

- MSX1 was based on VDP TMS9918 in 1983. TMS9918 was introduced in 1979 and there were more advanced VDP in 1983. For that age, TMS9918 was obsolete yet.

- MSX1 design had some flaw points. MSX expansion bus doesn't have Z80 Bus Request and Bus Acknowledge signals. These signals are requiere for DMA access. MSX designers chosed a 50 pins connector perhaps because this connector was cheaper than longer connectors. There were not enough pins for all Z80 signals (Z80 has 40 pins), slots, subslots, audio signal, etc. with a 50 pins connector. MSX standard never supported DMA!!! That's a big mistake! VDP and audio devices weren't able to access to CPU RAM without CPU intervention. That is a big bottleneck. Amiga used 40 DMA channels in 1985. This topic was discussed in this forum many years ago.

- MSX2 was a non finished machine (with V9938 VDP without horizontal scroll) when released because Commodore and Atari had already introduced new computers in 1985 and ASCII corporation had to give some alternative computer.

- Yamaha engineers were more interested in making good VDP designs for consoles than good VDP designs for MSX. Perhaps Sega paid them better than ASCII corp.

The sprites support of V9938 and V9958 was very limited. They only supported a bank of 32 sprites and 8 sprites with just 1 color plus transparency per sprite on same scanline. If you want sprites with 3 colors per scanline, you have to draw overlapped sprites with OR effect. With this, MSX2 and MSX2+ can only put 4 sprites (4 pairs of sprites) with 3 colors plus transparency on same scanline. On the other hand, a bank of 32 16x16 sprites is too short without flip x or y.

- For me, this is the main reason. MSX2 was released in 1985 and it was based on Z80. MSX2 should have been based on the succesor, the Z800, but Zilog released late (in 1985) and with poor tech specs. ASCII corporation wasn't able to design a 16 bit computer on time because Z800 wasn't available. If you want to release a computer based on Z800 in 1985 you need Z800 available a few years before.

Z800 was able to manage larger quantities of memory than Z80 (upto 16MB), but Z800 performance was similar to Z80. That's the reason of R800 existence. ASCII corporation wanted a quicker CPU.

Large applications require managing large quantities of memory. MSX Z80 can manage more than 64KBytes of memory by memory page swapping, but this method is slow and it has many drawbacks. If you make visible a memory page above 64KBytes of main RAM, you will have to loose the visibility of one of the current memory pages. This is a very big problem if you are programming large aplication with large and complex data structures. In fact, as far as I know, there isn't any C compiler for MSX that produces code that manages more than 64 KBytes of data and code. The development of such C compiler would be very complex and the code produced would be very slow.

Computers based on Motorola 68000 didn't have these kind of problems, and MC68000 had many succesors. Atari and Commodore paid a a little price, because ST and Amiga didn't have compatibility with 8bits systems, but the benefits were great from the point of view of development.

MSX standard couldn't change CPU because to do this would have been to destroy the MSX standard.

Wikipedia says that Z800 was released late because Zilog was most interested in the succesor of Z8000, the Z80000. Z8000 was an alternative CPU to Motorola 68000 and Zilog wanted to conquest servers market, but the main income of Zilog was Z80 solds. It was a very risky decision.

Anyway, the destiny of MSX had been the same. Perhaps MSX was a little bit longer. Its competitors didn't last much more.

By enribar

Paladin (1000)

enribar's picture

23-05-2019, 00:34

I think MSX2 was the only right thing to do in the 80s.
Your point o view is centered on videogames, and real powerful business machines were too expensive in 1985 (IBM PCs).
In 1985 MSX2 was:
- a standard that guaranteed profit margins to many companies;
- a backward generation compatible standard, it saves your past investments in hw and sw;
- a low cost mid-professional machine compatible CP-M and MS-DOS;
- a multimedia computer thank to great resolution, superimposing and digitization;
- an advanced music computer thank to Yamaha OPL;
- a very good game machine with a huge software catalogue, international and localized, with many killer applications and exclusives, all compatible across different countries;
- a technology that can be embedded or "hidden" in other devices like digital audio-video boards, coin-ops, communication terminals, public information totems, etc.;
- technologically more advanced than any other at that time, think about the many peripherals made by the great electronic companies;
- so, who really needed DMA and 16bits in 1985 with a machine like that and at that price?
For me, the only bad point about v9938 and the MSX concept was:
too ahead for those years ---> a computer system like the MSX2 came in 1995 with the multimedia PCs and Macs.

By Juan Luis

Resident (46)

Juan Luis's picture

23-05-2019, 01:42

I write this text extracted of Wikipedia:
https://en.wikipedia.org/wiki/MSX#Evolution

"Evolution
MSX spawned four generations: MSX (1983), MSX2 (1985),[14] MSX2+ (1988), and MSX TurboR (1990). The first three were 8-bit computers based on the Z80 microprocessor, while the MSX TurboR was based on a custom 16-bit R800 microprocessor developed by ASCII Corporation. By the time the MSX TurboR standard was announced in 1990, only Panasonic was manufacturing MSX computers. Its initial model FS-A1ST met with moderate success, but the upgraded model FS-A1GT introduced in 1991 sold poorly due to its high retail cost of 99800 yen. Production of the TurboR ended in 1993 when Panasonic decided to focus on the release of 3DO.[citation needed]
The MSX3 was scheduled for market in 1990. Delays in the development of its VDP—then named V9978 on the pre-release spec sheets—caused Yamaha to miss its time to market deadline.[15] In its place, an improved MSX2+ was released as the MSX TurboR; features of the new R800 processor such as DMA and 24-bit addressing were disabled. The VDP was eventually delivered two years after its planned deadline, by which time the market had moved on. In an attempt to reduce its financial loss, Yamaha stripped nearly all V9958 compatibility and marketed the resulting V9990 E-VDP III as a video-chipset for PC VGA graphic cards, with moderate success. Sony also employed the V7040 RGB encoder chip on many other products. MSX-FAN Magazine also mentions the impressive power of the V9990, being able to compete with much more expensive hardware such as Sharp's X68000. "

About CP/M, this video of 8 bits guy about Commodore 128 says that CP/M OS was dead in 1985. See the video between 22min44s and 23min11s. About MS-DOS, was MSX2 a MS-DOS compatible?
https://www.youtube.com/watch?v=wzMsgnnDIRE

By enribar

Paladin (1000)

enribar's picture

23-05-2019, 09:07

> About CP/M, this video of 8 bits guy about Commodore 128 says that CP/M OS was dead in 1985. See the video between 22min44s and 23min11s.

This was a feature +1 for a computer with his own operating system MSX-DOS, why not to consider the CP/M compatibility a good point: many professional applications of that time were compatible (Wordstar at the office, Wordstar at home, so why not?).

> About MS-DOS, was MSX2 a MS-DOS compatible?

Here in msx dot org I'm talking to an audience that clearly knows what "MSX-DOS compatible" means (= floppy disk format) ;-)
What an HELL with Commodore formats, a very closed system that it was clear it didn't go so far...

By PingPong

Prophet (3448)

PingPong's picture

23-05-2019, 11:32

Juan Luis wrote:

There were several limitations in MSX standard from the start. These are:

- MSX1 was based on VDP TMS9918 in 1983. TMS9918 was introduced in 1979 and there were more advanced VDP in 1983. For that age, TMS9918 was obsolete yet.

Excluding the VIC-II can you mention some more advanced VDP providing sprites/scroll abilities and other similar features?
I think there is no much choice as proved by contemporary computer design.
ZX Spectrum had it's own hw (ULA)
Amstrad CPC relied on MC6845 that i can hardly consider a better VDP than TMS. The major drawback in VDP is the absence of hw scrolling. Even the sprites, as limited they were is a less limiting factor than hw support for scrolling.

Please consider that the VIC-II had sprites (more advanced) like VDP because the idea of sprites was borrowed from TMS as said by a commodore VIC-II designer.

By DarkSchneider

Paladin (869)

DarkSchneider's picture

23-05-2019, 13:23

For me the changer was the MSX2+. Take a Zemmix and set it in Turbo Mode, with CPU around 10MHz? and VDP WAIT signal connected. With 256KB of RAM (and we can see that it was the original idea looking at Panasonic boards) and MSX-DOS2, we have a very good computer as an economic PC alternative (the DOS runs nicely).
I am very sure it was the original design, but manufacturers wanted to sell their refurbished MSX2 and other typical problems so the 2+ was finally a (short, 64KB) MSX2 with V9958.
That "real" MSX2+ can stand well until the release of the MSX3, with a new CPU, linear memory, and eveything improved, and not the improvised solution like the TurboR was.

The MSX2 is not bad with its V9938, the important thing is the software, and using SC4 and some tricks you can achieve many kind even console-style games, with its own style. Take more "Space Manbows" and probably there would be few complaints, but it was more easy no need to convert graphics to tiles, and screen type design is much easier than open map. What I miss more from MSX2, as the computer it is, is more CPU, it should have incorporated the Z80B, it is a good boost in general.

The MSX1 was made with fully computer in mind, so they focused about defining the standard and in text mode. Then it is true that we have a problem, as there was many MSX1 to ignore them when making software. And with the high cost of the computers, it is not easy to demand users to renew their machines by the new model.

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