]
] Alex,
]
] > ] With DOS2 cartridges, DOS1 bootsectors (yes, UZIX disk bootsector is DOS1)
] > ] also enable BDOS2???
] > ] If the answer is yes, HOW can I disable DOS2?
] > Answer is yes.
] > Answer to second question is: NOT. Though, there are three different
] > solutions to follow:
] > 1) Use the DOS2 mapper routines if DOS2 is present.
]
] The problem happens before it...
] A UZIX disk contains a DOS1 bootsector.
] Based on Duddu report, even the bootsector isn't executed
] correctly.
] I don't use DOS2 mapper routines, I have my own interrupt handler,
] I access diskROM directly (4010h). I don't use a single DOS2 function.
] Well, it's not very true. The bootsector uses BDOS to read the
] secondary bootstrap. It's all BDOS based, and should work with DOS2. Seems
] that even the string "UZIXboot: loading ZILO", printed by BDOS function
] #9, is not printed, based on Duddu's report. :/
I have had a look at your bootsector with a sectoreditor (called diskview)
under DOS2 and encountered a problem that might be related to the bootproblem.
What happened is the following:
1) I booted the TR from harddisk
2) I started the sectoreditor
3) I commanded the sectoreditor to look at the floppy drive
4) I received a 'Disk I/O error' message!
I have had this before, so the next thing I did was inserting some other
floppy and pointing the sectoreditor to the floppy drive again. The
sectoreditor switched to the floppy drive and showed me the contents of the
bootsector. After that I could insert the UZIX disk again and tell the
sectoreditor to re-read sector 0. Which worked. I looked at the DPB and saw
that you had set the following entries to zero:
0x10 : # Fat tables
0x11/0x12: # Directory entries
0x16/0x17: # Sectors per Fat
I rebooted my MSX, started the sectoreditor again with the UZIX disk in the
floppy drive. Again, the sectoreditor/dos2 refused to read the disk. I used
the diskchange trick again. After that I could change the boot sector of the
UZIX disk. I changed the above mentioned entries to one and wrote the boot
sector to disk.
After a second reboot of my MSX, I started the sectoreditor again. Now, the
sectoreditor could read the UZIX disk at one, without any error messages.
So, to make a long story short: it seems like DOS2 does some sanity checks on
the information in the drive parameter block and refuses to read a disk with
'invalid' parameters in the DPB.
You can try to make a new disk with these three parameters changed to one in
stead of zero. Thus:
change byte 0x10, 0x11 and 0x16 of the bootsector into one. After that, every
DOS2 cartridge should boot the disk.
Kind regards,
Alex Wulms
--
Alex Wulms/XelaSoft - MSX of anders NIX - Linux 4 ever
See my homepage for info on the *** XSA *** format
http://www.inter.nl.net/users/A.P.Wulms
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