China DOS Union

It's been a long time since I came to the forum. Does anyone still remember me?
Recently, I'm interested in grub for dos, but I don't understand many things. Am I getting old?
First, ask a question:
If I want to make a floppy disk image booted by grub, but the machine itself doesn't have a floppy drive, what should I do? Can I use vmware?
If there were previous posts discussing this, can you inform me of the address? Thanks!

Haha, found a gimage, someone has already made it ready-made.
Take it for me!

Haha!
Making a floppy disk image doesn't actually require a real floppy drive!

This question, I also have a doubt?
How to create a GRUB boot disk in VM?
Is there a limit on the size of the created IMG?

Probably in the VM, you can only create the maximum of 1.44M!

I made an IMG image of more than 3M. I imported the GRUB boot file BIN (I had previously stored the files in BOOT\GRUB into the image). As a result, when booting to GRUB (that is, it shows GRUB and then restarts).... Does GRUB not support images larger than 1.44M?

For the 3M IMG you created, you can do this:

bootlace --floppy your_IMG

Then find a way to copy the GRLDR and your own menu.lst files into this IMG (copy them to its root directory), and that's enough.

The above bootlace needs to be operated under DOS, or in the DOS window of WINDOWS 98, or in the command prompt of WIN2000/XP.

This BOOTLACE tool is provided by the new version of GRUB4DOS.

It supports not only 3M IMG floppy disks, but also any size of IMG floppy disk images.

Other files and directories not mentioned above are useless.

Thanks to user 7楼, TINYBIT~~~

But it seems I didn't find this command in the GRUB help file. I'll try it when I go back!

OK, it's okay `~~~~But there's another problem.
I want to call another IMG in the GRUB menu. I use the following format:

title Boot Efficiency Source Image File
root (fd0)
kernel (fd0)/tools/memdisk.gz
initrd (fd0)/tools/xly.img


Among them, the TOOLS folder contains MEMDISK.GZ and XLY.IMG,
But an error is prompted!
Error line:

kernel (fd0)/tools/memdisk.gz
ERROR26: attemp to access block outside partition!
I don't understand, ask for help!

[ Last edited by coolboy163 on 2005-11-18 at 10:47 ]

It's not possible to judge whose bug this is yet. If it's a GRUB4DOS bug, there's hope for it to be resolved soon. Can you upload this 3M IMG file you made?

I wonder if you've tried the following boot methods:

title Boot Efficiency Source Image File - Simulate Floppy Disk
map --mem (fd0)/tools/xly.img (fd0)
map --floppies=1
map --hook
chainloader (fd0)+1
rootnoverify (fd0)
boot

title Boot Efficiency Source Image File - Simulate Hard Disk
map --mem (fd0)/tools/xly.img (hd0)
map --harddrives=1
map --hook
chainloader (hd0)+1
rootnoverify (hd0)
boot

Thanks to TINYBIT's enthusiastic guidance, this method hasn't been tried yet. I'll try it when I get back. Sometimes it makes sense in theory, but it doesn't work in practice.
I looked for some information. Could it be such a problem?
After memdisk.gz, the three parameters of the disk, C, H, S, need to be added. If it's a standard 1.44M, then there's no need to add them.
For example: kernel (fd0)/tools/memdisk.gz Otherwise, you need to add c=xx h=xx s=xx after it.
I don't have time to work on it now. I'll study it when I get home

According to your description, your error is in the kernel line. Kernel is a command of GRUB. This should be an error when GRUB reads the memdisk.gz file, and it seems to have nothing to do with c=xx h=xx s=xx.

I suspect that the BIOS does not recognize your floppy disk. If the size of your floppy disk exceeds the range limited by the BIOS, then the BIOS may not accept it. If so, then it cannot be solved. For example, some floppy drives only support 1.44M floppy disks and do not support larger floppy disks. If you can normally open files such as memdisk.gz under DOS (for example, you can copy all files in the floppy disk to the hard disk under pure DOS), then it indicates that there is a BUG in the GRUB kernel command.

Just saw that you're using a VMWARE virtual machine. This virtual machine doesn't support floppy disks larger than 1.44M. Try changing to one, like QEMU, and it should work. QEMU is a very excellent open-source virtual machine software, much more powerful than VMWARE. It can run on many platforms, including CPUs other than x86, such as Apple's, SUN's, SGI's. Of course, it runs best under x86 platform LINUX and WINDOWS. This makes this virtual machine software become more and more popular.

Thanks~~~

TINYBIT is really very enthusiastic, just finished being busy.
Just now I modified it using your method, heh heh, now the problem is relatively obvious
Prompt:
map --mem(fd0)/tools/xyl.img(fd0)
autodetect number-of-heads failed.user default value 2
autodetect sectors-per-tract failed.user default value 63
ERROR26:attemp to access blockouside partition!
press any key to continue........

Could it really be an issue with VM? Only supports <1.44M?
Thank you again TINYBIT, I'm just learning GRUB, being able to meet such a good person is really very lucky, now my understanding of GRUB is getting deeper and deeper. Now the information on the Internet is relatively superficial, and what I find is all the same. (Maybe I'm too stupid, can't find it)

[ Last edited by coolboy163 on 2005-11-18 at 16:44 ]

For this situation, rearranging your xyl.img might solve the problem, that is, store xyl.img within 1.44M so that DOS and BIOS can access it. Just now, a rough test showed that QEMU also doesn't support floppy disks larger than 1.44M.

In fact, many real - machine BIOSes don't support large floppy disks larger than 2.88M, so we can't really blame virtual machines like VMWARE and QEMU.

But fortunately, GRUB4DOS supports floppy disks of any size. You can try the following operation, and it should succeed if there are no unexpected situations:

First, enter the GRUB4DOS environment from the hard disk. Suppose your 3M IMG is on (hd0,0). Enter the following command sequence at the GRUB prompt:

map --mem (hd0,0)/your_3M_img (fd0)
map --floppies=1
map --hook
chainloader (fd0)+1
rootnoverify (fd0)
boot

After entering the floppy disk, you can continue to operate your xly.img.

Or, simply put xly.img on the hard disk and then directly use a similar method with GRUB4DOS to run it.