Diskrom mirror differences between openMSX en BlueMSX

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Por Manuel

Ascended (18704)

Imagen del Manuel

01-02-2007, 20:12

Yes, you can use an external drive. The dump of the slot with the disk drive interface would also be nice, but do tell me what kind of drive it is exactly (e.g. Philips VY-0010).
I'm interested in the slot with the subROM and the slot with the diskROM.
The subROM of the 8220 is also in slot 3-0.

You can find out in which slot the diskROM and/or subROM is located by using getrom.bin, which is on the same page as saverom.com. YOu don't need to dump the ROMs with that (they can be extracted from the slot dumps you make with saverom.com), but you can just see in which slot the ROMs are located.

In this program (start with: BLOAD"GETROM.BIN",R), you can see output like this:

No. Slot Description
1   0-0  MSX2 BIOS
2   3-0 MSX2 Extended BIOS
3   3-3 BDOS (Disk BIOS) Version 2.2

This means I'm interested in slot 3-0 (sub ROM) and slot 3-3 (disk ROM).

With this info, it should be possible to find out the FDC register mirroring and sub ROM mirroring behaviour of any MSX machine Smile

Por msxrestarter

Master (224)

Imagen del msxrestarter

01-02-2007, 21:15

@ manuel : romdumps of 8220 and 8235 are in your mailbox Wink

Por Manuel

Ascended (18704)

Imagen del Manuel

01-02-2007, 23:17

Interesting, the FDC mirroring of the 8235 is the same as the '45: only in page 2, unlike the 8230 (no mirroring).

I made a simple overview of the data here: http://openmsx.sourceforge.net/techinfo/mirroring.html

Por dvik

Prophet (2200)

Imagen del dvik

01-02-2007, 23:34

@manuel: Very nice table Smile interesting results too.

Por Manuel

Ascended (18704)

Imagen del Manuel

02-02-2007, 20:50

Interesting: a dump from the disk ROM of the Philips VY-0010 shows at the end:
MSX disk basic system... 1985/06/20 version....presented by JVC... (MAEBASHI) Japan. Designed by S. Isozaki..

Um, JVC??

A little bit before that, you can find:
MSX disk basic system presented by Victor company of Japan, LTD.
VICTOR
This driver soft is made for 3.5 inchesfloppy disk drive with side detector. Formatter automatically selects side. May 21st,1984 by K.Totsuka
Victor Company of Japan, Limited
JVC KT2

The best thing of all: the text at the end of the ROM is printed when you type CALL GETVER!

How interesting...

Por zeilemaker54

Champion (338)

Imagen del zeilemaker54

02-02-2007, 22:44

@manuel: thanx for your e-mail. A first look at the diskdrivers of the VY-0010, VG-8230 and VG-8235 learns that they are indeed close relatives! You can see the evolution in the drivercode. So it looks like the first version of the diskdriver was developed by JVC and adjusted by Philips on the VG-8230 and VG-8235. It looks like VY-0010 and VG-8230 are working with a drive WITHOUT the READY signal. That is why the driver must detect the not-ready status otherwise. Most likely some bug is in this routine, that is why in this case "Write Protect" error is generated. More to come....

Por Kwik

Expert (127)

Imagen del Kwik

03-02-2007, 15:06

@zeilemaker: What about the kernel part (i don't know if it is called that, but i mean the part with the INIT, BDOS calls, bootsector execution, etc.). Is that the same in every diskrom? We have developed a patch for a 8250 diskrom, to use with our Nowind USB diskrom. We only replaced the driver part. If the kernel part is the same in every diskrom, then the patch could be applied to all diskroms (not only the 8250).

Por zeilemaker54

Champion (338)

Imagen del zeilemaker54

05-02-2007, 14:32

@Kwik: If you mean DOS1: As far as I know, there are two versions. There only a small number of bugfixes in the second version but have no impact on the driver section. You can see which bugs are fixed in the msxsyssrc project, disk.mac in folder disk100 and look for BUGFIX.

@zeilemaker: What about the kernel part (i don't know if it is called that, but i mean the part with the INIT, BDOS calls, bootsector execution, etc.). Is that the same in every diskrom? We have developed a patch for a 8250 diskrom, to use with our Nowind USB diskrom. We only replaced the driver part. If the kernel part is the same in every diskrom, then the patch could be applied to all diskroms (not only the 8250).

Por Kwik

Expert (127)

Imagen del Kwik

05-02-2007, 20:05

@zeilemaker: I've said it before, but those sources are great!

Por zeilemaker54

Champion (338)

Imagen del zeilemaker54

07-02-2007, 12:00

It seems that the VY0010 has a very early version of the DOS1 kernel, which I have not seen before. Very interesting stuff......

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