中国DOS联盟

This is like this. I use bcdw to boot the zjz.img image. Among them, the zjz.img has been written with the boot code by bootlace --floppy --chs zjz.img, and grldr (version 0.4.3 is added. It is found that version 0.4.4 cannot display Chinese) and other related files in menu.lst. In zjz.img, there is a zjzdos.img with a capacity of 56.8 MB. The map --mem /zjzdos.img (fd0) in menu.lst successfully starts it. I want to compress to reduce the volume. The zjzdos.img in zjz.img is compressed to zjzdos.zip, and the volume changes from 56.8 MB to 34.9 MB. Put it in zjz.img. In menu.lst, use
kernel /memdisk.gz c=63 h=64 s=32 floppy
initrd /zjzdos.zip
Boot zjz.img with bcdw. After Grub4DOS in zjz.img starts zjzdos.zip, it prompts:



And the zjzdos.img in the inner zjzdos.zip can be bootstrapped by Grub4DOS alone. The chs parameter calculation is also correct. c is the rounded value. I have changed c to 64 and 63, and neither end works. Please help from Grub4DOS experts on how to make it start successfully.

Last edited by xiaoyunwang on 2008-10-22 at 16:41 ]

It should be that the production of the img is not very standard. Memdisk has relatively high requirements for the img, and the map method can be used for booting.

I don't know why I like to use the way of nesting img in img. What are the advantages?

Reducing the size of a .zip file from 56.8 MB to 34.9 MB. When using Esboot (or Bcdw) to create a CD menu, it is required that the reading and writing of A: for extremely large .IMG files be successful. Therefore, after esboot starts the IMG, Grub4DOS is used to start another IMG (the real IMG tool image) so that A: can be read and written (because chainloader /io.sys cannot read and write A:, so only IMG nested in IMG is used). Now it's unlucky. I used the ones released by fastslz which are said to be more able to make Grub4DOS boot successfully than other IMG images. I selected a very large one. After making it, it only starts successfully with map --mem. After compressing into .ZIP, it fails to boot.

Last edited by xiaoyunwang on 2008-10-25 at 10:03 ]

bcdw--grub--img.gz, isn't the effect the same? The boot efficiency should be even higher.

memdisk.gz is a tool in syslinux. Usually, when there are problems with booting using it, it has nothing to do with grub4 anymore.

The emulation function of grub4 itself is much more powerful than memdisk. For example, it can directly boot ISO, can perform disk mapping, load multiple images at the same time, and boot images without specifying the chs value, etc. If you don't have a special preference for memdisk or use it as a backup option, actually, grub4 doesn't need it. Just note that grub4 supports the gzip compression format.

Therefore, only from the perspective of reducing the volume, the building owner can just use grub4, and memdisk and bcdw can be removed. Because grub4 itself can well support various boot media and boot methods.

Last edited by zw2312914 on 2008-10-25 at 18:46 ]

Both map and memdisk are retained, preferably in both ways, to achieve the best compatibility.

It turns out that Grub4DOS can directly boot .GZ compressed IMG images. It seems I need to study more. I'll give it a try. It's said that booting with Grldr is not universal, and using the Grub.exe program is better. I wonder if that's the case.

Last edited by xiaoyunwang on 2008-10-26 at 13:08 ]

Originally posted by xiaoyunwang at 2008-10-26 13:03:
It turns out that Grub4DOS can directly boot .GZ compressed IMG images. It seems I need to learn more. Let me give it a try. It is said that booting with Grldr is not universal, and using the Grub.exe program is better. I wonder if that's the case. ...

Personally, I think Grldr should be better than Grub.exe.

The method of bcdw--grldr--img.gz should not be worse than the method you use of bcdw--img--grldr--img.gz.
Since we are considering the universality issue, both use Grldr, rather than you using Grub.exe for booting and me using Grldr. Hehe.

Of course, the compatibility performance of Grub in different methods is just a speculation. How exactly it is, still needs the author's explanation.

That's great. Thanks a lot. It turns out that Grub4DOS can really directly boot the .GZ compressed .IMG image. I won't have a preference for memdisk boot and .ZIP compressed formats. I saw that many large images are booted with memdisk after compression. I originally thought Grub4DOS couldn't boot directly compressed images. Some related articles on the Internet also said so. I tried it recently and learned something new again.

Last edited by xiaoyunwang on 2008-10-26 at 13:39 ]

Originally posted by lianjiang2004 at 2008-10-26 01:23 PM:

Personally, I think grldr is better than grub.exe.

The method of bcdw--grldr--img.gz should not be worse than the method of bcdw--img--grldr--img.gz you are using.
Since it is considering the versatility issue, both use grld ...

That's for sure, thanks to brother lianjiang

bcdw--grldr--img.gz
bcdw--grub--img.gz

I'll take another close look at your tutorial (I read it and then forgot).
It may still be necessary for me to learn how to get Chinese menus and place Chinese menus on the background image. grub4dos 0.4.3 can get Chinese menus, but 0.4.4 can't, using the same operation method.

Maps cannot be compressed, while map --mem supports compression. Early articles were generally based on GNU GRUB and did not have the map --mem function. Also, since few people use large 3 - 50MB IMGs, there is no need for compression. It is also troublesome to handle after compression.

Update 3: Beginning at version 0.4.0, GRUB for DOS supports memdrives.
Example:

# boot into a floppy image
map --mem (hd0,0)/floppy.img (fd0)
map --hook
chainloader (fd0)+1
rootnoverify (fd0)
map --floppies=1
boot

Because the image will be copied to a memory area, the image
itself can be non-contiguous and even gzipped.

Originally posted by lianjiang2004 at 2008-10-26 05:10 PM:
Update 3: Beginning at version 0.4.0, GRUB for DOS supports memdrives.
Example:

# boot into a floppy image
map --mem (hd0,0)/floppy.img (fd0)
map --hook
chainloader (fd0)+1
...

Another new problem arises. For some reason, only the Chinese Grldr in Grub4DOS dated 2008-3-14 can boot map --mem /boot/grub/zjzdos.gz (fd0). When booting with the Chinese Grldr in the latest version of Grub4DOS dated 2008-10-22, it still reports "Non-system disk (zjzdos.gz is 38 MB):



Could it be that the latest version is not as good as the earlier version? So depressed!

When solving other bugs, introducing new bugs is not impossible. For the problems in the new version, you need to report to the official website.