At 05:25 PM 03/25/99 -0300, you wrote:
>I don't think that (mega)ROM cartridges are interesting. They're hard to
>copy, unmodifiable (in principle) and much expensive.
They are nice if you collect games. But if you only want to play them, disk
combined with mappper/MegaRAM is easier and cheaper.
>Some Brazilian guys are fanatical crackers but not for piracy, just for
>fun! Japanese software was copy protected because they knew that WE would
>copy it, not the most part of the Japaneses.
I don't think a commercial company would care if their games are copied in
a country where they aren't available in the stores.
>> Cartridge is extra quality (no loading time, more durable) compared to
>> disk. Also, it is harder to copy.
>
>And much much much more expensive! The cost/benefit relation is much
>poorer than for disks.
Most of what you pay for a game is not the hardware, but the development.
Even if ROM hardware is a lot more expensive than disks, it will make only
a small difference on the selling price.
>> Henrik Gilvad once told me.
>
>Is he the guy that created the IDE interface for MSX?
Yes. And also the MoonSound, GFX9000 and some other hardware.
>> >Then, there's still a chance only for Turbo-R.
>>
>> The built-in FDC can handle HD according to Henrik. But you would need to
>> write a new diskROM...
>
>Yes, and some hardware modifications, too.
My turbo R already has a HD drive inside, to replace the broken original
drive. Other modifications wouldn't be necessary, would they?
>> For normal MSX1/2/2+, 7MHz is an option. But old FDCs can't handle HD
>> speeds either, so they would have to be replaced.
>
>Some people say that WD2793 can handle 500kbit/s transfer rate. Is it
>true?
I'm not sure. I heard that FDCs of MSX2s (don't know the part number)
weren't fast enough. But I've never verified that.
>> But a Superdisk drive is quite expensive, maybe someone wants to make a
>> buffered HD floppy interface? It could be very simple: two banks of 512
>> bytes (1 sector) of RAM. Could be two ICs or a single dual-ported IC. One
>> bank is filled by the FDC, while the other is LDIR-ed to MSX main RAM.
>> Although 3.5MHz is too slow for polling the FDC, it would be fast enough
>> for LDIR-ing. After LDIR-ing an entire sector it would poll for moment the
>> next sector is available.
>
>My idea was a buffer for an entire track (or maybe cylinder?)
Would that make any difference in performance?
I think that if the "read sector" command can be given within the time a
sector gap takes to pass the drive head, reading single sectors will
already occur at top speed.
>> It would be a real benefit:
>> - 720K disks are hard to find, 1.44MB disks are still available everywhere
>> - double the amount of data fits on a single disk
>> - disk transfer rate is doubled, making your MSX load faster
>> Anyone interested in making a prototype?
>
>I am interested, but I don't know how should I create a diskrom compatible
>with the common diskroms.
A diskROM for 1.44MB disks has two main features:
- sector reading using the new floppy interface (easy to make)
- support for 1.44MB floppy filesystem (may be difficult?)
Anyway, the person who makes the hardware doesn't have to worry too much
about the software. Designing the hardware and designing a sector read
routine is something that should be done together. But all the other
modifications to the diskROM are purely a software issue.
>The biggest problem is that I don't have enough time, nowadays.
A big problem for many MSXers... :(
Bye,
Maarten
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