12 replies to this topic

[wimb]

I have a problem booting DOS Superfloppy Images since grub4dos-0.4.4-2008-09-30

I have two DOS Superfloppy Images:
- 25 MB MS-DOS FAT16 probed C/H/S = 25/64/32 - 51200 total sectors
- 15 MB FreeDOS FAT12 probed C/H/S = 15/64/32 - 30720 total sectors

For MS-DOS the message is: Invalid system disk.
For FreeDOS I get message: FreeDOS with flashing cursor.

All previous versions of grub4dos e.g. grub4dos-0.4.4-2008-09-29 and older are booting fine my DOS Superfloppy Images and using in menu.lst on HD or USB-stick with NTFS or FAT format:

title FREEDOS Image

find --set-root /BTFRDOS.img

map /BTFRDOS.img (fd0)

map --hook

chainloader (fd0)+1

rootnoverify (fd0)

By using about 10 different versions of grub4dos grldr from
http://nufans.net/grub4dos/history/
and thanks to the ChangeLog_GRUB4DOS.txt
I can say that the origin of the problem is most likely this fix:

2008-09-30 fixed a big bug in set_bootdev causing extra rawread executed and the geometry messed up.

The small 2880 KB DOS floppy Images do NOT have such boot problem with recent GRUB4DOS versions.

[ireneuszp]

Try with memdisk
http://syslinux.zyto...dex.php/MEMDISK

title FREEDOS Image

find --set-root /BTFRDOS.img

kernel /memdisk

initrd /BTFRDOS.img

[wimb]

For image size over 2880 KB then memdisk expects Image to have a harddisk like structure with MBR and partition table.

In any case the current 15 - 25 MB DOS Superfloppy images (without MBR) are not bootable via memdisk.
May be I can rebuild the image, so that it contains an MBR and partition table.
I will try that. Thanks for mentioning the memdisk option.

But the question remains:

Can we use recent grub4dos grldr (build since grub4dos-0.4.4-2008-09-30) to boot 15-25 MB DOS Superfloppy Images, like the previous versions were able to do.

[tinybit]

@wimb

Can you please upload the image?

You may build a small test image and compress it and upload it.

[wimb]

FreeDOS Superfloppy Image of 15 MB - FAT12 is Uploaded to
http://wimb.winbuilder.net/downloads/

It is my original BTFRDOS.img with only the non-free dosapps removed.

grub4dos-0.4.4-2008-09-29 and older are booting this Superfloppy Image, but all more recent grub4dos versions fail to boot this image.

@tinybit
I hope you can solve the issue.
Please let me know if you need more info or other images.

[ireneuszp]

Try this

title FREEDOS Image

find --set-root /BTFRDOS.img

map /BTFRDOS.img (fd0)

map --hook

chainloader (fd0)/kernel.sys

[wimb]

Try this

title FREEDOS Image

find --set-root /BTFRDOS.img

map /BTFRDOS.img (fd0)

map --hook

chainloader (fd0)/kernel.sys

Perfect, FreeDOS Superfloppy Image boots now with all versions of grub4dos grldr

Nice solution to the problem, thanks.

And the 25 MB MS-DOS Superfloppy Image is now for all grldr versions bootable with:

title MS-DOS Superfloppy Image 25 MB

find --set-root /BTMSDOS.img

map /BTMSDOS.img (fd0)

map --hook

chainloader (fd0)/IO.SYS

@tinybit
Does the present solution give some insight in the cause of the original boot problem ?

[tinybit]

I have just downloaded the image. I'll look into this issue. Please wait.

[was_jaclaz]

For image size over 2880 KB then memdisk expects Image to have a harddisk like structure with MBR and partition table.

Just for the record, NO.

http://www.911cd.net...showtopic=10853
http://www.911cd.net...showtopic=11096

jaclaz

[wimb]

I tried to use memdisk and to specify C/H/S and floppy as:

title FREEDOS Image 15 MB - via memdisk

find --set-root /BTFRDOS.img

kernel /memdisk c=15 h=64 s=32 floppy

initrd /BTFRDOS.img



title MS-DOS Image 25 MB - via memdisk

find --set-root /BTMSDOS.img

kernel /memdisk c=25 h=64 s=32 floppy

initrd /BTMSDOS.img

The funny thing is that memdisk understands the given parameters and will treat it as a floppy, but unfortunately fails to boot the DOS Superfloppy Images for all tried versions of grldr.

[was_jaclaz]

The funny thing is that memdisk understands the given parameters and will treat it as a floppy, but unfortunately fails to boot the DOS Superfloppy Images for all tried versions of grldr.

Most probably, since the problem is solved by directly chainloading the system files (thus bypassing the bootsector) is the bootsector itself that is not entirely and fully "right".

Or maybe the nx64x32 is not "liked" by memdisk.

jaclaz

[tinybit]

@wimb

Problem solved. Thank you very much for your reporting.

http://nufans.net/gr...-2009-06-11.zip

[wimb]

@tinybit

Thanks for solving the problem

DOS Superfloppy Images are booting fine now using menu.lst entry as given in post #1