China DOS Union

Please interested brothers and sisters test the search function of the GRLDR boot code.

Place the GRLDR file in the root directory of any disk, any partition, the boot code of GRLDR can find it.

The test method is like this: first delete all GRLDR on the machine, copy the new GRLDR file to the root directory of C: disk and rename it to GRLDR1. Modify boot.ini, add a line C:\GRLDR1="GRLDR1", start with this line, it must not find the GRLDR file, but the whole process of finding GRLDR should be displayed on the screen, all your hard disks and all partitions should be listed, if there are unlisted hard disks or partitions, it is regarded as a BUG.

After the above test is completed, then test: copy GRLDR to the root directory of a certain hard disk and a certain partition, still use the above line C:\GRLDR1="GRLDR1" to start, see if this time GRUB starts smoothly. If it does not start, it is regarded as a BUG.

Download address: ftp://ftp.linuxeden.com/tinybit/grldr

This file is constantly updated. If the initial test fails, download it again after two days and keep testing it. Thank you.


You can also do the third test: After the above hard disk partition search is completed, it will search for floppy disk A: (but never search for floppy disk B. So now delete GRLDR on the hard disk, place GRLDR in the root directory of the floppy disk, and see if the above boot code of GRLDR1 can find it.


Fourth test: If all the above searches fail, then it will try to boot a previously backed up MBR. The second sector of the first hard disk hd0, that is, the sector immediately following the MBR, can be used to store any boot sector you want to place. It can be an old MBR, or a partition boot record, such as a DOS boot record, or any other boot code you write. No matter what you place, it is called the previous MBR (this is just a name). The last two bytes of this boot code must be the usual 55, AA to be considered a legal boot sector, otherwise it will not be booted. Okay, use DEBUG or other tools to write the boot sector you want to boot into the second sector of hd0, and delete GRLDR on the hard disk and floppy disk, then test whether the above GRLDR1 can boot it. (Since there is an operation to write to the hard disk here, so I should still remind you, this is very dangerous. Brothers who are not proficient in using DEBUG, do not try it yourself, otherwise your hard disk will be easily destroyed.)


Further technical implementation: At the very beginning of the GRLDR file, there is a two-byte jmp instruction. The byte immediately following this instruction, that is, the third byte (at offset 0x02), is not part of the program code, but is used to control the search operation mode of GRLDR. When the 0th bit of this control byte is set to 1, the search for the floppy disk is prohibited. When the 1st bit of this control byte is set to 1, a previous MBR without a partition table is prohibited from booting. At this time, the backed up previous MBR is required to be your previous MBR indeed, not a partition boot record of a certain partition. The other bits of this control byte are reserved for future use. This control byte is 0 by default, that is, it prohibits nothing, and all operations are in the maximum open state. The use of this control byte is clear, and the user program can freely write this byte according to their own needs (of course, pay attention not to damage the other bytes that should not be written, especially when this sector is in the MBR, of course, be more careful).

I have extracted the boot part of GRLDR into GRUB.DAT..... You can load GRUB.DAT in BOOT.INI or with an NT floppy to start and automatically find GRLDR in the root directory of each partition, which solves the original limitation that GRLDR could only be on the system disk..... Download: http://bbs.wuyou.com/cgi - bin/topic.cgi?forum=34&topic=7201&show=0

Great!

As you have noticed, the boot code of GRLDR is the first 16 sectors located at the beginning of GRLDR. The GRUB.DAT you make must be at least 16 sectors (that is, 8192 bytes). It can be more than 16 sectors, but it must not be less. If it is less, the search may fail. If it is more than 8192 bytes, the extra bytes have no effect (but there is no harm either).

Can I boot the GRLDR on the logical partition? I haven't tested it yet. Please, Brother BuDian, give me some guidance... Also, I can't download the MEMDRIVR you mentioned. Could you send it to my mailbox for testing? hnlyzhd@163.com

The GRLDR on the logical partition can be booted, but, as usual, it only searches its root directory.

Under Linux, you can manually log in to ftp.linuxeden.com using the ftp command to download. The wget command is sometimes ineffective, and there is a long period of no response when executing the PASV command. Those download tools under Windows, such as FlashGet,影音传送带 and so on, are all completely ineffective, and the manifestation is also losing response when executing the PASV command. It is estimated that this is some kind of virus doing, quite powerful, but unfortunately it seems that no one has reported this virus.

There is also a command under Linux that can deal with this situation. Try downloading with curl, which generally succeeds:

curl --ftp-port 20 -C - -O ftp://ftp.linuxeden.com/tinybit/grldr

Read it out:

curl space double hyphen ftp slash port space 20 space double hyphen uppercase C space hyphen space double hyphen uppercase O space followed by the URL address.

Under Windows, it also seems impossible to log in manually using FTP.

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I will send it to you, but not now, because I still need to make changes, and then send you the revised new version.

Thanks...The several files mentioned earlier have been downloaded, but there is no MEMDRIVE. Just send it to my mailbox when you're done. Thanks again..I have a GRUB learning area set up on Wuyou. If you have time, please come here to give some guidance. Gandalf also often visits http://bbs.wuyou.com/cgi-bin/topic.cgi?forum=34&topic=5697&show=0

Well then, there's no need to send emails anymore because you've obtained all the files you need, which are any one of grub.exe, grldr, grub4lin. Note that they will keep getting updated.

Hello, Brother Budian! I would like to ask you the following questions: When I installed GRUB without compiling scdrom into the floppy disk (using stage1 and stage2), to boot from the CD-ROM, I had to rely on BCDL.BIN and VIDE-CDD.SYS.

Boot from CD-ROM
root (fd0)
chainloader /boot/grub/cdboot.bs
In order to free up more space for the floppy boot disk, I want to compile scdrom into stage2, so that scdrom --bootcd can boot from the CD-ROM. How can I compile scdrom into the Stage2 of GRUB under Windows or DOS? I don't have a Linux environment and don't know the compilation method. Is there a difference between grub-0.96-patch6-scdrom and grub-0.96-patch7-bioscdrom? Can I compile the latest version of scdrom into the Stage2 of an older version of GRUB such as version 0.90? Because I don't need new functions, I just want stage2 to be small and support booting from the CD-ROM. I sincerely ask for your advice, thank you!

Upstairs, please don't do repetitive work. The 0.95 version of S\TAGE2 already supports SCDROM

There are two methods. The first one is to use the version made by gandalf. The scdrom module was actually provided by him. Because I can't solve the bugs I encountered, I don't plan to maintain this module anymore. The program he extracted from the smart boot manager, I can't understand it too well, so I can't continue to maintain it.

The second method is to call the most original sbm.bin from GRUB for DOS. This method can also boot the CDROM. sbm.bin comes from the smart boot manager. You can search for this file on the Internet, download it and use it. The method to call sbm.bin in grub4dos can also be found on the Internet. For example, there are introductions on http://grub.linuxeden.com. sbm.bin is only 18K, which should be acceptable.

The bioscdrom module was written by myself. Currently, it can only be used for some old models of ASUS machines, so it is basically useless. Just don't compile it. This module has basically stopped being maintained because this matter is not very important and it is not a priority to be solved. In the future, when I have free time, I will consider enhancing it.

You can't compile GRUB without Linux. If you really want to compile, it's still better to install a Linux.

The easiest way is to just wait and wait for gandalf to make a reliable version and use it directly.

Although there is still a scdrom patch in my release, I can't be sure that it still works now because I haven't tested it. For this reason, I won't provide a release with a binary file containing the scdrom module.

In conclusion, gandalf is very familiar with this. It's best to contact him if you have any questions.

1. gandlaf has changed jobs and is very busy with no time to develop GRUB2. His version supporting SCDROM is already very good.
Title: Boot from CD
scdrom --bootcd
Using the two commands scdrom --bootcd is enough. Booting from the CD - ROM is an old problem with GRUB, and it's already very good like this.
3. It is suggested that Brother Budian add the function of installing to the hard disk for GRLDR, write it to the MBR, and only look for GRLDR when pressing the hotkey; otherwise, boot normally from the hard disk (GANDLAF has written a similar STAGE1 file).

Brother Budian, when you are modifying the chainloader function, see if you can boot the following BIOS module...{{{http://bbs.wuyou.com/cgi-bin/attachment.cgi?forum=33&topic=1387&postno=9&type=.rar&name=Idiopf_1108629898}}}}}

> Press the hotkey to look for GRLDR, otherwise boot normally from the hard disk

The idea is really interesting, thumbs up. Currently implemented is to first look for GRLDR, and if it fails, then boot the previous MBR backup. I will consider making some changes to make the order of priority controllable.

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What is the structure of that BIOS module? What position in memory is it loaded into? How much space does it occupy in memory?

I don't need to open it, as long as I know these situations, I will know whether I can use chainloader to do it.

Starting GRUB on a logical partition is unstable, sometimes it fails to boot successfully, and the Chinese font appears garbled when loading.