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Grub4DOS - DOS 6.22 Boot Problem


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#1 wiesl

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Posted 20 February 2012 - 07:16 AM

Hello,

I'm having the following problem with Grub4DOS (grub4dos-0.4.5c-2012-02-14.7z). I'm starting (currently) grub4dos from NT4 BOOT.INI:

Config:
BOOT.INI:
C:\GRLDR="GRUB4DOS"

MENU.LST (partly):

# OK:
title MS-DOS 6.22 (find and load BOOTSECT.620 of MS-DOS 6.22)
find --set-root --ignore-floppies /BOOTSECT.620
chainloader /BOOTSECT.620
#savedefault --wait=2

# NOT OK:
title SEGMENT MS-DOS 6.22 (find and load IO.SYS of MS-DOS 6.22)
find --set-root --ignore-floppies --ignore-cd /io.sys
chainloader --force --load-segment=0x70 --msdos /io.sys
#savedefault --wait=2

# NOT OK:
title MS-DOS 6.22 (find and load IO.SYS of MS-DOS 6.22)
find --set-root --ignore-floppies --ignore-cd /io.sys
chainloader --msdos /io.sys
#savedefault --wait=2

Message is:
Will boot MS-DOS from drive=0x80, partition=0x0(hidden sectors=0x3f)
Starten von MS-DOS...
(Starting MS-DOS)

Any ideas?

Thnx.

Wiesl

BTW: Following works well (MENU.LST)
title Windows NT 4.0 (find and load NTLDR of Windows NT 4.0)
find --set-root --ignore-floppies --ignore-cd /ntldr
chainloader --force --load-segment=0x2000 /ntldr
#savedefault --wait=2

title Windows NT 4.0 (find and load NTLDR of Windows XP SP3)
find --set-root --ignore-floppies --ignore-cd /ntldrxp
chainloader /ntldrxp
#savedefault --wait=2

title FREELDR
find --set-root --ignore-floppies --ignore-cd /freeldr.sys
kernel /freeldr.sys
#savedefault --wait=2

#2 steve6375

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Posted 20 February 2012 - 09:06 AM

I just use

chainloader /io.sys

or chainloader /kernel.sys for FreeDOS

which seems to work OK.

In what way does it not work?

#3 Wonko the Sane

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Posted 20 February 2012 - 09:42 AM

Historically DOS 6.22 io.sys was not supported, did it change with a newer 0.4.5? :unsure:
http://reboot.pro/14013/

:cheers:
Wonko

#4 wiesl

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Posted 20 February 2012 - 10:52 AM

Historically DOS 6.22 io.sys was not supported, did it change with a newer 0.4.5? :unsure:
http://reboot.pro/14013/


I'm using as discussed in original post already latest version 0.4.5: grub4dos-0.4.5c-2012-02-14.7z

Is already supported since commit:
https://code.google....ce/detail?r=169

What's strange, that it is booted, but then it crashes/doesn't continue. So it looks like an environmental issue.
Will boot MS-DOS from drive=0x80, partition=0x0(hidden sectors=0x3f)
Starten von MS-DOS...
(Starting MS-DOS)

Any ideas?

Thnx.

Wiesl

#5 wiesl

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Posted 20 February 2012 - 10:54 AM

I just use

chainloader /io.sys

or chainloader /kernel.sys for FreeDOS

which seems to work OK.

In what way does it not work?


Which exact version do you use?

As discussed startups MS-DOS but then hangs.
Starten von MS-DOS...
(Starting MS-DOS)

Thnx.

Wiesl

#6 Wonko the Sane

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Posted 20 February 2012 - 11:05 AM

Strange.
The commit is on May 18, 2011
If I were you - for test - I would try the immediately later build:
https://code.google....-19.7z&can=2&q=
(there is a possibility of a "regression bug")
From changelog:

2011-05-19 applied Roy's patch(Issue 27: adding PC-DOS/MS-DOS chainloading support).



Have you tried it with an ENGLISH MS-DOS 6.22 IO.SYS? :unsure:
It is possible that the patch is language-dependant? :dubbio:

:cheers:
Wonko

#7 steve6375

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Posted 20 February 2012 - 11:10 AM

I get the same issue - but is there a difference between a floppy and a hard disk set of MSDOS boot files - are you using the 'floppy' files to boot a 'hard disk' drive?

#8 wiesl

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Posted 20 February 2012 - 11:13 AM

Strange.
The commit is on May 18, 2011
If I were you - for test - I would try the immediately later build:
https://code.google....38;can=2&q=
(there is a possibility of a "regression bug")


Have you tried it with an ENGLISH MS-DOS 6.22 IO.SYS? :unsure:
It is possible that the patch is language-dependant? :dubbio:


Will try new version in the evening.

Didn't try ENGLISH MS-DOS 6.22 (no test system available).
As far as I looked at the source (only partially) all values which are checked are the same.

Do you have a suggestion where to look at the source?

Thnx.

Wiesl

#9 wiesl

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Posted 20 February 2012 - 11:16 AM

I get the same issue - but is there a difference between a floppy and a hard disk set of MSDOS boot files - are you using the 'floppy' files to boot a 'hard disk' drive?


Don't know. My old DOS system was only installed on harddisk and was migrated to virtual machine :-) Therefore I assume hard drive boot files ...

How does your testcase look like? Working? Non working?

Thnx.

Wiesl

#10 Wonko the Sane

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Posted 20 February 2012 - 05:51 PM

@Wiesl
Due to the "other" issues here:
http://reboot.pro/14013/
I just tested latest-latest (grub4dos-0.4.5c-2012-02-14.7z) in Qemu and a "plain":
root (hd0,0)

chainloader /io.sys

boot


works here (with English Dos 6.22) on a hard disk image that has "standard" DOS 6.22 bootsector and fdisked/formatted by DOS 6.22 itself (i.e. system files are "first").

Can you detail:
  • Filesystem used
  • Which bootsector you have
  • Position of IO.SYS and MSDOS.SYS in the Root directory

So that I can try to reproduce....

:cheers:
Wonko

#11 steve6375

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Posted 20 February 2012 - 06:27 PM

OK - I found the problem! :clap: . RMPrepUSb is using a partition type for FAT16 of 0Eh in the MBR ptn table - if I change this to 06h then it boots fine!
I noticed this because I booted to a FAT16 working USB drive with a DOS622 Floppy image (boot as A:) with the other 'bad' RMPrepUSB prepared USB drive connected and DOS did not see a drive C:, but it did see a drive C: when I prepared the same USB drive with the 'good' FAT16 image.

So it seems DOS 6.22 looks at the active partition type sometime during msdos.sys but before command.com and hangs if it is 'wrong'...

#12 Wonko the Sane

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Posted 20 February 2012 - 06:45 PM

So it seems DOS 6.22 looks at the active partition type sometime during msdos.sys but before command.com and hangs if it is 'wrong'...

Well, actually DOS 6.x knows nothing about 0E or 0B/0C.
BTW, with Extended partition one should be careful with 05/0F. :ph34r:
AFAICR it only knows about:
  • 01
  • 04
  • 05
  • 06
  • 07 (07 will be tagged HPFS)
all the rest being "a suffusion of yellow".

Some details are here:
http://www.win.tue.n...on_types-1.html

Current links to relevant MS KB's:
http://support.micro...kb/148821/en-us
http://support.micro...kb/151414/en-us

The built-in Windows (2K/XP) FORMAT has a "provision" and sets the 06 when applicable, compare with:
http://reboot.pro/3191/page__st__26

I guess RMPREPUSB should behave the same :unsure:.

:cheers:
Wonko

#13 wiesl

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Posted 20 February 2012 - 06:49 PM

Can you detail:

  • Filesystem used
  • Which bootsector you have
  • Position of IO.SYS and MSDOS.SYS in the Root directory

So that I can try to reproduce....



Filesystem used: FAT16
Bootsectors:
a.) MBR: NT4.0 bootsector/German which boots VBR
b.) VBR: NT4.0 which boots NTLDR boot menu
Position of IO.SYS and MSDOS.SYS in the Root directory: I know what it is, which tools do you recommend to see?
(from disk editor it looks like 1.) io.sys, 2.) msdos.sys, 3.) command.com, etc.)

Thnx.

Wiesl

#14 wiesl

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Posted 20 February 2012 - 06:52 PM

Will try new version in the evening.

Didn't try ENGLISH MS-DOS 6.22 (no test system available).
As far as I looked at the source (only partially) all values which are checked are the same.

Do you have a suggestion where to look at the source?

Thnx.

Wiesl


Old version after commit also doesn't work.

Wiesl

#15 Wonko the Sane

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Posted 20 February 2012 - 07:02 PM

Hmmm, and the partition ID must be 06 otherwise NT wouldn't have a chance. :unsure:

Is it possible for you to setup a Qemu VM (ideally with Qemu Manager)?

Or, make a dd-like copy of first 64 sectors of your hard disk, zip it and attach/post it to a file hosting site and post the link?

:cheers:
Wonko

#16 wiesl

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Posted 20 February 2012 - 07:09 PM

OK - I found the problem! :clap: . RMPrepUSb is using a partition type for FAT16 of 0Eh in the MBR ptn table - if I change this to 06h then it boots fine!
I noticed this because I booted to a FAT16 working USB drive with a DOS622 Floppy image (boot as A:) with the other 'bad' RMPrepUSB prepared USB drive connected and DOS did not see a drive C:, but it did see a drive C: when I prepared the same USB drive with the 'good' FAT16 image.

So it seems DOS 6.22 looks at the active partition type sometime during msdos.sys but before command.com and hangs if it is 'wrong'...


Thanx for pointing that out but my MBR has type 6h in the partition table. So it should work but doesn't.

It is also quite logical that this can't be the reason: Because when selecting C:BOOTSECT.620 from NT boot loader (NTLDR) which is then loaded as VBR partition table isn't touched at all.

From Linux fdisk partition types:
6: FAT16
13 (e): W95 FAT16 (LBA)

https://en.wikipedia...ter_boot_record

Any further ideas?

Thnx.

Wiesl

#17 steve6375

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Posted 20 February 2012 - 07:42 PM

What about position of the files on the disk? I think that they have to be at the beginning of the disk. Is the FAT16 partition the first one?
Maybe post first 64 sectors as Wonko requested?
You can use RMPrepUSB - ALLDRIVES (ALT+F5), then click on Drive->File and use 65SEC as the length.

#18 wiesl

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Posted 20 February 2012 - 07:55 PM

What about position of the files on the disk? I think that they have to be at the beginning of the disk. Is the FAT16 partition the first one?
Maybe post first 64 sectors as Wonko requested?
You can use RMPrepUSB - ALLDRIVES (ALT+F5), then click on Drive->File and use 65SEC as the length.


Yes, they are on the first position. FAT16 partition is also the first partition. First 63 sectors don't have usefull content except MBR (partition starts afterwards).

Wiesl

#19 steve6375

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Posted 20 February 2012 - 08:18 PM

I guess RMPREPUSB should behave the same :unsure:.
Wonko

New version of RMPrepUSB/RMPartUSB (v2.1.639 and later) will use Type 06 if FAT16 is selected and CHS is selected.

#20 wiesl

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Posted 20 February 2012 - 08:18 PM

Yes, they are on the first position. FAT16 partition is also the first partition. First 63 sectors don't have usefull content except MBR (partition starts afterwards).

Wiesl


As this is in a QEMU VM I have logged sector readings after selecting DOS from NTLDR (reads BOOTSECT.620) or after grub selection with io.sys reading:

One can see that last 3 sector reads right (nok side) are different.
right reads correctly MSDOS.SYS, scsi-disk: Read (sector 2931542, count 37)
Not working version doesn't read MSDOS.SYS but garbage.

So it looks like IO.SYS is read correctly (reads from scsi-disk: Read (sector 2931414, count 39), verified)

Any further ideas to track it down?

Thnx.

Wiesl


diff -dy dos_iosys_ok.log dos_iosys_nok.log

scsi-disk: Read (sector 63, count 1)						  | scsi-disk: Read (sector 0, count 63)

scsi-disk: Read (sector 566, count 1)						 | scsi-disk: Read (sector 63, count 63)

scsi-disk: Read (sector 567, count 1)						 | scsi-disk: Read (sector 504, count 63)

scsi-disk: Read (sector 568, count 1)						 | scsi-disk: Read (sector 2931390, count 63)

scsi-disk: Read (sector 569, count 1)						 | scsi-disk: Read (sector 0, count 63)

scsi-disk: Read (sector 570, count 1)						 | scsi-disk: Read (sector 63, count 63)

scsi-disk: Read (sector 571, count 1)						 | scsi-disk: Read (sector 504, count 63)

scsi-disk: Read (sector 572, count 1)						 | scsi-disk: Read (sector 2931390, count 63)

scsi-disk: Read (sector 573, count 1)						 | scsi-disk: Read (sector 0, count 63)

scsi-disk: Read (sector 574, count 1)						 | scsi-disk: Read (sector 63, count 63)

scsi-disk: Read (sector 575, count 1)						 | scsi-disk: Read (sector 0, count 63)

scsi-disk: Read (sector 576, count 1)						 | scsi-disk: Read (sector 504, count 63)

scsi-disk: Read (sector 577, count 1)						 | scsi-disk: Read (sector 567, count 63)

scsi-disk: Read (sector 578, count 1)						 | scsi-disk: Read (sector 0, count 63)

scsi-disk: Read (sector 579, count 1)						 | scsi-disk: Read (sector 63, count 63)

scsi-disk: Read (sector 580, count 1)						 | scsi-disk: Read (sector 504, count 63)

scsi-disk: Read (sector 581, count 1)						 | scsi-disk: Read (sector 2931390, count 63)

scsi-disk: Read (sector 582, count 1)						 | scsi-disk: Read (sector 2931453, count 63)

scsi-disk: Read (sector 63, count 1)						  | scsi-disk: Read (sector 189, count 63)

scsi-disk: Read (sector 566, count 1)						 | scsi-disk: Read (sector 2931453, count 63)

scsi-disk: Read (sector 567, count 1)						 <

scsi-disk: Read (sector 568, count 1)						 <

scsi-disk: Read (sector 569, count 1)						 <

scsi-disk: Read (sector 570, count 1)						 <

scsi-disk: Read (sector 571, count 1)						 <

scsi-disk: Read (sector 572, count 1)						 <

scsi-disk: Read (sector 573, count 1)						 <

scsi-disk: Read (sector 574, count 1)						 <

scsi-disk: Read (sector 575, count 1)						 <

scsi-disk: Read (sector 576, count 1)						 <

scsi-disk: Read (sector 577, count 1)						 <

scsi-disk: Read (sector 578, count 1)						 <

scsi-disk: Read (sector 579, count 1)						 <

scsi-disk: Read (sector 580, count 1)						 <

scsi-disk: Read (sector 581, count 1)						 <

scsi-disk: Read (sector 582, count 1)						 <

scsi-disk: Read (sector 63, count 1)						  <

scsi-disk: Read (sector 566, count 1)						 <

scsi-disk: Read (sector 567, count 1)						 <

scsi-disk: Read (sector 568, count 1)						 <

scsi-disk: Read (sector 569, count 1)						 <

scsi-disk: Read (sector 570, count 1)						 <

scsi-disk: Read (sector 571, count 1)						 <

scsi-disk: Read (sector 572, count 1)						 <

scsi-disk: Read (sector 573, count 1)						 <

scsi-disk: Read (sector 574, count 1)						 <

scsi-disk: Read (sector 575, count 1)						 <

scsi-disk: Read (sector 576, count 1)						 <

scsi-disk: Read (sector 577, count 1)						 <

scsi-disk: Read (sector 578, count 1)						 <

scsi-disk: Read (sector 579, count 1)						 <

scsi-disk: Read (sector 580, count 1)						 <

scsi-disk: Read (sector 581, count 1)						 <

scsi-disk: Read (sector 582, count 1)						 <

scsi-disk: Read (sector 63, count 1)						  <

scsi-disk: Read (sector 566, count 1)						 <

scsi-disk: Read (sector 567, count 1)						 <

scsi-disk: Read (sector 568, count 1)						 <

scsi-disk: Read (sector 569, count 1)						 <

scsi-disk: Read (sector 570, count 1)						 <

scsi-disk: Read (sector 571, count 1)						 <

scsi-disk: Read (sector 572, count 1)						 <

scsi-disk: Read (sector 573, count 1)						 <

scsi-disk: Read (sector 574, count 1)						 <

scsi-disk: Read (sector 575, count 1)						 <

scsi-disk: Read (sector 576, count 1)						 <

scsi-disk: Read (sector 577, count 1)						 <

scsi-disk: Read (sector 578, count 1)						 <

scsi-disk: Read (sector 579, count 1)						 <

scsi-disk: Read (sector 580, count 1)						 <

scsi-disk: Read (sector 581, count 1)						 <

scsi-disk: Read (sector 582, count 1)						 <

scsi-disk: Read (sector 63, count 1)						  <

scsi-disk: Read (sector 566, count 1)						 <

scsi-disk: Read (sector 567, count 1)						 <

scsi-disk: Read (sector 568, count 1)						 <

scsi-disk: Read (sector 569, count 1)						 <

scsi-disk: Read (sector 570, count 1)						 <

scsi-disk: Read (sector 571, count 1)						 <

scsi-disk: Read (sector 572, count 1)						 <

scsi-disk: Read (sector 573, count 1)						 <

scsi-disk: Read (sector 574, count 1)						 <

scsi-disk: Read (sector 575, count 1)						 <

scsi-disk: Read (sector 576, count 1)						 <

scsi-disk: Read (sector 577, count 1)						 <

scsi-disk: Read (sector 578, count 1)						 <

scsi-disk: Read (sector 579, count 1)						 <

scsi-disk: Read (sector 580, count 1)						 <

scsi-disk: Read (sector 581, count 1)						 <

scsi-disk: Read (sector 582, count 1)						 <

scsi-disk: Read (sector 0, count 1)						   <

scsi-disk: Read (sector 63, count 1)						  <

scsi-disk: Read (sector 566, count 1)						 <

scsi-disk: Read (sector 277, count 3)						 <

scsi-disk: Read (sector 3525974, count 1)					 <

scsi-disk: Read (sector 3525974, count 1)					 <

scsi-disk: Read (sector 566, count 1)						 <

scsi-disk: Read (sector 2931414, count 1)					 <

scsi-disk: Read (sector 2931415, count 1)					 <

scsi-disk: Read (sector 2931416, count 1)					 <

scsi-disk: Read (sector 2931414, count 39)					  scsi-disk: Read (sector 2931414, count 39)

scsi-disk: Read (sector 2931453, count 25)					  scsi-disk: Read (sector 2931453, count 25)

scsi-disk: Read (sector 242, count 1)						   scsi-disk: Read (sector 242, count 1)

scsi-disk: Read (sector 2931478, count 38)					  scsi-disk: Read (sector 2931478, count 38)

scsi-disk: Read (sector 2931516, count 26)					  scsi-disk: Read (sector 2931516, count 26)

scsi-disk: Read (sector 0, count 1)							 scsi-disk: Read (sector 0, count 1)

scsi-disk: Read (sector 63, count 1)							scsi-disk: Read (sector 63, count 1)

scsi-disk: Read (sector 0, count 1)							 scsi-disk: Read (sector 0, count 1)

scsi-disk: Read (sector 32, count 1)							scsi-disk: Read (sector 32, count 1)

scsi-disk: Read (sector 0, count 1)							 scsi-disk: Read (sector 0, count 1)

scsi-disk: Read (sector 63, count 1)							scsi-disk: Read (sector 63, count 1)

scsi-disk: Read (sector 0, count 1)							 scsi-disk: Read (sector 0, count 1)

scsi-disk: Read (sector 0, count 1)							 scsi-disk: Read (sector 0, count 1)

scsi-disk: Read (sector 0, count 1)							 scsi-disk: Read (sector 0, count 1)

scsi-disk: Read (sector 0, count 1)							 scsi-disk: Read (sector 0, count 1)

scsi-disk: Read (sector 0, count 1)							 scsi-disk: Read (sector 0, count 1)

scsi-disk: Read (sector 0, count 1)							 scsi-disk: Read (sector 0, count 1)

scsi-disk: Read (sector 242, count 1)						 | scsi-disk: Read (sector 257, count 1)

scsi-disk: Read (sector 2931542, count 37)					| scsi-disk: Read (sector 3168342, count 54)

scsi-disk: Read (sector 2931579, count 63)					| scsi-disk: Read (sector 3168396, count 10)

scsi-disk: Read (sector 2931642, count 28)					<

scsi-disk: Read (sector 64, count 1)						  <

scsi-disk: Read (sector 566, count 1)						 <

scsi-disk: Read (sector 567, count 1)						 <

scsi-disk: Read (sector 568, count 1)						 <

scsi-disk: Read (sector 569, count 1)						 <

scsi-disk: Read (sector 570, count 1)						 <

scsi-disk: Read (sector 571, count 1)						 <

scsi-disk: Read (sector 572, count 1)						 <

scsi-disk: Read (sector 573, count 1)						 <

scsi-disk: Read (sector 574, count 1)						 <

scsi-disk: Read (sector 575, count 1)						 <

scsi-disk: Read (sector 576, count 1)						 <

scsi-disk: Read (sector 577, count 1)						 <

scsi-disk: Read (sector 578, count 1)						 <

scsi-disk: Read (sector 579, count 1)						 <

scsi-disk: Read (sector 580, count 1)						 <

scsi-disk: Read (sector 581, count 1)						 <

scsi-disk: Read (sector 582, count 1)						 <

scsi-disk: Read (sector 566, count 1)						 <

scsi-disk: Read (sector 567, count 1)						 <

scsi-disk: Read (sector 568, count 1)						 <

scsi-disk: Read (sector 569, count 1)						 <

scsi-disk: Read (sector 566, count 1)						 <

scsi-disk: Read (sector 567, count 1)						 <

scsi-disk: Read (sector 568, count 1)						 <

scsi-disk: Read (sector 569, count 1)						 <

scsi-disk: Read (sector 328406, count 1)					  <

scsi-disk: Read (sector 84, count 1)						  <



#21 Wonko the Sane

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Posted 20 February 2012 - 08:25 PM

Yes, they are on the first position. FAT16 partition is also the first partition. First 63 sectors don't have usefull content except MBR (partition starts afterwards).

Wiesl

Good :), then post just the MBR and the PBR, with those I can re-build an image and make a few tests.
Sorry but I cannot make head or tail of your last post. :ph34r:
If you want help in troubleshooting the issue, please provide what I asked for, so that I can do a few tests.


@Steve
Very good. :thumbsup:
You should add a check for size, though, CHS has a limit at 1024/16/63, around 500 Mb, and one at 1024/255/63, i.e. anything bigger that 8 Gb, actually 8,422,686,720 would become "a suffusion of yellow".
I haven't checked at which size the 2K/XP Format would "switch", though, maybe it does so at a smaller size than 500 Mb for FAT16 and possibly the same switch happens at the larger size for FAT32.

:cheers:
Wonko

#22 wiesl

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Posted 20 February 2012 - 08:50 PM

Good :), then post just the MBR and the PBR, with those I can re-build an image and make a few tests.
Sorry but I cannot make head or tail of your last post. :ph34r:
If you want help in troubleshooting the issue, please provide what I asked for, so that I can do a few tests.


@Steve
Very good. :thumbsup:
You should add a check for size, though, CHS has a limit at 1024/255/63, i.e. anything bigger that 8 Gb, actually 8,422,686,720 would become "a suffusion of yellow".
I haven't checked at which size the 2K/XP Format would "switch", though, maybe it does so at a smaller size.

:cheers:
Wonko



00000000  fa 33 c0 8e d0 bc 00 7c  8b f4 50 07 50 1f fb fc  |.3.....|..P.P...|

00000010  bf 00 06 b9 00 01 f2 a5  ea 1d 06 00 00 be be 07  |................|

00000020  b3 04 80 3c 80 74 0e 80  3c 00 75 1c 83 c6 10 fe  |...<.t..<.u.....|

00000030  cb 75 ef cd 18 8b 14 8b  4c 02 8b ee 83 c6 10 fe  |.u......L.......|

00000040  cb 74 1a 80 3c 00 74 f4  be 8b 06 ac 3c 00 74 0b  |.t..<.t.....<.t.|

00000050  56 bb 07 00 b4 0e cd 10  5e eb f0 eb fe bf 05 00  |V.......^.......|

00000060  bb 00 7c b8 01 02 57 cd  13 5f 73 0c 33 c0 cd 13  |..|...W.._s.3...|

00000070  4f 75 ed be a7 06 eb d3  be cd 06 bf fe 7d 81 3d  |Ou...........}.=|

00000080  55 aa 75 c7 8b f5 ea 00  7c 00 00 55 6e 67 81 6c  |U.u.....|..Ung.l|

00000090  74 69 67 65 20 50 61 72  74 69 74 69 6f 6e 73 74  |tige Partitionst|

000000a0  61 62 65 6c 6c 65 00 46  65 68 6c 65 72 20 62 65  |abelle.Fehler be|

000000b0  69 6d 20 4c 61 64 65 6e  20 64 65 73 20 42 65 74  |im Laden des Bet|

000000c0  72 69 65 62 73 73 79 73  74 65 6d 73 00 42 65 74  |riebssystems.Bet|

000000d0  72 69 65 62 73 73 79 73  74 65 6d 20 66 65 68 6c  |riebssystem fehl|

000000e0  74 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |t...............|

000000f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000100  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000110  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000120  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000130  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000140  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000150  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000160  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000170  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000180  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

00000190  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

000001a0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

000001b0  00 00 00 00 00 00 00 00  51 10 0b 0a 00 00 80 01  |........Q.......|

000001c0  01 00 06 c3 7f 4b 3f 00  00 00 91 8d 3e 00 00 00  |.....K?.....>...|

000001d0  41 4c 07 c3 ff fa d0 8d  3e 00 04 71 81 00 00 00  |AL......>..q....|

000001e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

000001f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|



00007e00  eb 3c 90 4d 53 44 4f 53  35 2e 30 00 02 40 01 00  |.<.MSDOS5.0..@..|

00007e10  02 00 02 00 00 f8 fb 00  3f 00 c4 00 3f 00 00 00  |........?...?...|

00007e20  57 8d 3e 00 80 00 29 ce  16 59 1d XX XX XX XX XX  |W.>...)..Y.XXXXX|

00007e30  XX XX XX 20 20 20 46 41  54 31 36 20 20 20 33 c0  |XXX   FAT16   3.|

00007e40  8e d0 bc 00 7c 68 c0 07  1f a0 10 00 f7 26 16 00  |....|h.......&..|

00007e50  03 06 0e 00 50 91 b8 20  00 f7 26 11 00 8b 1e 0b  |....P.. ..&.....|

00007e60  00 03 c3 48 f7 f3 03 c8  89 0e 08 02 68 00 10 07  |...H........h...|

00007e70  33 db 8f 06 13 02 89 1e  15 02 0e e8 90 00 72 57  |3.............rW|

00007e80  33 db 8b 0e 11 00 8b fb  51 b9 0b 00 be dc 01 f3  |3.......Q.......|

00007e90  a6 59 74 05 83 c3 20 e2  ed e3 37 26 8b 57 1a 52  |.Yt... ...7&.W.R|

00007ea0  b8 01 00 68 00 20 07 33  db 0e e8 48 00 72 28 5b  |...h. .3...H.r([|

00007eb0  8d 36 0b 00 8d 3e 0b 02  1e 8f 45 02 c7 05 f5 00  |.6...>....E.....|

00007ec0  1e 8f 45 06 c7 45 04 0e  01 8a 16 24 00 ea 03 00  |..E..E.....$....|

00007ed0  00 20 be 86 01 eb 03 be  a2 01 e8 09 00 be c1 01  |. ..............|

00007ee0  e8 03 00 fb eb fe ac 0a  c0 74 09 b4 0e bb 07 00  |.........t......|

00007ef0  cd 10 eb f2 c3 50 4a 4a  a0 0d 00 32 e4 f7 e2 03  |.....PJJ...2....|

00007f00  06 08 02 83 d2 00 a3 13  02 89 16 15 02 58 a2 07  |.............X..|

00007f10  02 a1 13 02 8b 16 15 02  03 06 1c 00 13 16 1e 00  |................|

00007f20  f7 36 18 00 fe c2 88 16  06 02 33 d2 f7 36 1a 00  |.6........3..6..|

00007f30  88 16 25 00 a3 04 02 a1  18 00 2a 06 06 02 40 3a  |..%.......*...@:|

00007f40  06 07 02 76 05 a0 07 02  32 e4 50 b4 02 8b 0e 04  |...v....2.P.....|

00007f50  02 c0 e5 06 0a 2e 06 02  86 e9 8b 16 24 00 cd 13  |............$...|

00007f60  0f 83 05 00 83 c4 02 f9  cb 58 28 06 07 02 76 11  |.........X(...v.|

00007f70  01 06 13 02 83 16 15 02  00 f7 26 0b 00 03 d8 eb  |..........&.....|

00007f80  90 a2 07 02 f8 cb 42 4f  4f 54 3a 20 43 6f 75 6c  |......BOOT: Coul|

00007f90  64 6e 27 74 20 66 69 6e  64 20 4e 54 4c 44 52 0d  |dn't find NTLDR.|

00007fa0  0a 00 42 4f 4f 54 3a 20  49 2f 4f 20 65 72 72 6f  |..BOOT: I/O erro|

00007fb0  72 20 72 65 61 64 69 6e  67 20 64 69 73 6b 0d 0a  |r reading disk..|

00007fc0  00 50 6c 65 61 73 65 20  69 6e 73 65 72 74 20 61  |.Please insert a|

00007fd0  6e 6f 74 68 65 72 20 64  69 73 6b 00 4e 54 4c 44  |nother disk.NTLD|

00007fe0  52 20 20 20 20 20 20 00  00 00 00 00 00 00 00 00  |R	  .........|

00007ff0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 55 aa  |..............U.|

Attached Files

  • Attached File  MBR.doc   512bytes   100 downloads
  • Attached File  VBR1.doc   512bytes   96 downloads


#23 steve6375

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Posted 20 February 2012 - 09:29 PM

@Steve
Very good. :thumbsup:
You should add a check for size, though, CHS has a limit at 1024/255/63, i.e. anything bigger that 8 Gb, actually 8,422,686,720 would become "a suffusion of yellow".
:cheers:
Wonko

FAT16 ptn has 2GB limit so should be OK. :suda:

#24 steve6375

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Posted 20 February 2012 - 09:33 PM

your boot sector is trying to load NTLDR not IO.SYS!

#25 wiesl

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Posted 21 February 2012 - 06:34 AM

your boot sector is trying to load NTLDR not IO.SYS!


According to the sector readings above it reads IO.SYS and then tries to read MSDOS.SYS but from wrong location. You'll find the relevant first sectors below.

Yes, as discussed above on disk VBR is from NT4. But I think it shouldn't matter as code from GRUB4DOS tries to read IO.SYS from FAT. But maybe it relies on data in the VBR which is not correct as it is a NT4 VBR.

Normally NTLDR is loaded and from the BOOT SECTION from BOOT.INI it loads/executes BOOTSECT.620
C:\BOOTSECT.620="MS-DOS" /win95dos

Thnx.

Wiesl


IO.SYS

hexdump -s 1500883968 -n 512 -Cv VM.img

5975ac00  e9 35 01 06 16 00 00 00  00 00 00 00 00 00 00 00  |.5..............|

5975ac10  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ac20  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ac30  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ac40  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ac50  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ac60  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ac70  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ac80  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ac90  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975aca0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975acb0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975acc0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975acd0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ace0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975acf0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ad00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ad10  00 ff ff 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ad20  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

5975ad30  00 00 00 00 00 00 00 00  2e 89 1e 23 01 2e 88 2e  |...........#....|

5975ad40  2f 01 2e 88 16 2d 01 2e  89 36 31 01 1e 2e 8f 06  |/....-...61.....|

5975ad50  33 01 33 c9 8e d9 06 8e  c1 8b 36 78 00 8e 1e 7a  |3.3.......6x...z|

5975ad60  00 bf 22 05 b9 0b 00 fc  f3 a4 06 1f c7 06 78 00  |.."...........x.|

5975ad70  22 05 8c 1e 7a 00 07 8b  0e 0b 7c 2e 89 0e 1b 01  |"...z.....|.....|

5975ad80  8a 0e 0d 7c 2e 88 0e 37  01 8b 0e 18 7c 2e 89 0e  |...|...7....|...|

5975ad90  2b 01 8b 0e 1a 7c 2e 89  0e 05 01 8b 0e 16 7c 2e  |+....|........|.|

5975ada0  89 0e 15 01 8b 0e 0e 7c  2e 89 0e 1d 01 8b 0e 1c  |.......|........|

5975adb0  7c 2e 89 0e 17 01 8b 0e  13 7c 2e 89 0e 27 01 80  ||........|...'..|

5975adc0  3e 26 7c 29 75 1e 2e a3  25 01 a1 1e 7c 2e a3 19  |>&|)u...%...|...|

5975add0  01 83 f9 00 75 0e a1 20  7c 2e a3 27 01 a1 22 7c  |....u.. |..'.."||

5975ade0  2e a3 29 01 fc 33 f6 8b  fe cd 12 b1 06 d3 e0 33  |..)..3.........3|

5975adf0  db 8e db 8b 1e bc 00 8e  1e be 00 81 7f 03 52 50  |..............RP|



MSDOS.SYS

hexdump -s 1500949504 -n 512 -Cv VM.img

5976ac00  e9 9d 7c f0 3d 70 00 00  00 06 16 38 02 01 02 39  |..|.=p.....8...9|

5976ac10  03 03 02 05 3a 04 10 03  02 05 3b 02 02 03 3c 04  |....:.....;...<.|

5976ac20  03 02 04 05 3d 06 03 02  0c 04 1a 05 3e 01 06 3f  |....=.......>..?|

5976ac30  02 06 05 40 02 06 05 41  03 03 02 05 42 02 06 01  |...@...A....B...|

5976ac40  43 04 03 02 01 05 44 05  0f 0d 01 06 05 45 02 06  |C.....D......E..|

5976ac50  04 46 02 06 04 47 02 1a  0f 48 02 07 08 49 02 07  |.F...G...H...I..|

5976ac60  09 4a 03 07 09 08 4b 08  03 01 02 04 0b 0a 08 05  |.J....K.........|

5976ac70  4e 03 03 02 12 4f 01 12  56 05 11 03 02 10 05 57  |N....O..V......W|

5976ac80  04 06 08 0d 01 58 01 01  5a 04 03 02 04 05 5b 05  |.....X..Z.....[.|

5976ac90  50 03 02 04 05 5c 04 06  01 24 21 65 02 01 02 66  |P....\...$!e...f|

5976aca0  02 01 02 68 01 06 67 03  04 08 01 6c 0a 03 02 0c  |...h..g....l....|

5976acb0  04 50 08 1a 0d 01 05 69  04 0f 0d 01 05 ff 30 a2  |.P.....i......0.|

5976acc0  19 55 22 55 d8 55 f5 55  fb 55 55 54 84 54 f3 51  |.U"U.U.U.UUT.T.Q|

5976acd0  4d 52 59 52 0f 56 19 56  da 4d b1 4c 05 5d c1 56  |MRYR.V.V.M.L.].V|

5976ace0  18 5e ac 5e 5e 56 04 5e  09 5e ea 5d 32 57 26 44  |.^.^^V.^.^.]2W&D|

5976acf0  ac 4c a1 4c 66 4d 68 4d  26 44 26 44 aa 4d 26 44  |.L.LfMhM&D&D.M&D|

5976ad00  0e 5e 13 5e 72 56 46 56  d3 4c ef 4e ff 5d fa 5d  |.^.^rVFV.L.N.].]|

5976ad10  5b 4d 72 48 8f 48 af 48  c0 48 7f 4a 8d 4c 55 4a  |[MrH.H.H.H.J.LUJ|

5976ad20  d4 a1 ac 4d 6b 40 92 4d  c3 4c 64 4c 02 4d 86 4a  |...Mk@.M.LdL.M.J|

5976ad30  1a 61 62 60 9e 60 20 b0  49 af 64 a7 73 a8 d9 a8  |.ab`.` .I.d.s...|

5976ad40  72 b0 de a8 2d b0 7b 61  94 a9 b4 a9 e9 5f c7 a2  |r...-.{a....._..|

5976ad50  4c a4 28 a4 98 9b 0c a2  8e 9b 1f 5f 77 5f c2 40  |L.(........_w_.@|

5976ad60  ce 40 9e 4d 0f 4e 7a 4a  de 4e 98 b0 46 a9 82 a4  |.@.M.NzJ.N..F...|

5976ad70  16 4d 23 b1 0b b1 12 b3  6b a5 83 aa e4 a9 e2 ae  |.M#.....k.......|

5976ad80  26 44 ce 40 43 4d da 40  11 4b 0f 4c b1 a7 97 a7  |&D.@CM.@.K.L....|

5976ad90  f7 4f 97 a7 26 44 bd b1  e3 44 8c 3f 30 27 47 67  |.O..&D...D.?0'Gg|

5976ada0  6e f7 4c 21 47 a0 90 24  55 7c 93 24 99 68 6f d9  |n.L!G..$U|.$.ho.|

5976adb0  9a c9 b3 a3 6b 8c 6b 07  49 69 50 1d 99 69 50 32  |....k.k.IiP..iP2|

5976adc0  50 4a 50 4b 90 61 99 b0  9a dd a6 4c ab 9b 42 f5  |PJPK.a.....L..B.|

5976add0  aa 07 af b1 49 4b 4a a5  49 10 50 36 aa a6 a6 e2  |....IKJ.I.P6....|

5976ade0  ae 4d 44 81 81 69 50 58  50 0d 51 64 a7 13 51 73  |.MD..iPXP.Qd..Qs|

5976adf0  a8 cd 50 50 51 3f 51 6d  51 72 51 26 44 4d 53 2d  |..PPQ?QmQrQ&DMS-|



GARBAGE:

hexdump -s 1622191104 -n 512 -Cv VM.img

60b0ac00  02 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ac10  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ac20  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ac30  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ac40  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ac50  00 00 00 00 00 ca 00 cc  00 00 00 00 00 00 00 00  |................|

60b0ac60  00 04 00 55 26 00 00 00  00 00 00 00 00 00 00 00  |...U&...........|

60b0ac70  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ac80  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ac90  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0aca0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0acb0  00 00 00 00 00 00 00 00  ca 00 cc 9a 00 00 00 00  |................|

60b0acc0  00 00 00 00 04 00 c6 2a  00 00 00 00 00 00 00 00  |.......*........|

60b0acd0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ace0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0acf0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad10  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad20  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad30  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad40  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad50  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad60  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad70  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad80  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ad90  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ada0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0adb0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0adc0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0add0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0ade0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

60b0adf0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|






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