China DOS Union

Download address: http://grub4dos.jot.com/

There were the following developments on 2007-11-18:

1. Support for ISO emulation. Both ISO files in no-emulation bootable mode and those in floppy or hard disk emulation bootable mode are supported. Usage example:

map (hd0,0)/myiso.iso (hd32)
map --hook
chainloader (hd32)
boot

Explanation: (hd32) is equal to (128 + 32), which is (0xA0). When using map emulation, if the user specifies a disk number greater than or equal to 0xA0, the map command recognizes this as ISO emulation. That is, the sector size of the virtual disk at this time is 2048 bytes (only in this way can it be used as a CD, which is stipulated by the "bootable CD specification"), instead of the usual 512-byte sector size in floppy disks and hard disks.

2. For real CD-ROM boot (usually after running cdrom --init), it also supports booting from real "emulated floppy disk" and "emulated hard disk" format CD-ROM discs. Note: The previous version only supported booting from real CD-ROM discs in no-emulation format.

Please test and report all possible problems.

Okay, I'll try it right away.

Report:
My hardware configuration:
Motherboard name Gigabyte GA-K8NE
Disk drive - ST3160215A (149 GB)
Bootable floppy disk image is normal.
Booting Deep Mountain Red Leaf's v22 version CD image and CD image in floppy boot mode fails!
Prompt:
map (hd0,0)/myiso.iso (hd32)
Error 60 : File for drive emulation must be in one contiguous disk area
Press any key to continue...

[ Last edited by bc12060101 on 2007-11-18 at 09:04 PM ]

This is not a failure. Because the emulation without --mem always requires the file to be contiguous. There is a tool called contig that can be used to organize disk files and merge fragments into a continuous sector sequence. After organizing, you can use it normally.

If the machine has ample memory, you can use the following instead:

map --mem (hd0,0)/myiso.iso (hd32)

In this way, there will be no error reported on the continuity issue.

A few days ago I was still thinking that if only grub could simulate a CD-ROM, but unexpectedly it has really been implemented. Worth testing

According to the guidance of Brother Budian, after reconfiguring the menu with map --mem (hd0,0)/myiso.iso (hd32), it can boot into the system through the CD image.

My CD image is a tool CD that uses easyboot to make a set of Shenshan Hongye tool disk (V22), a streamlined XP installation version, and some DOS tools (floppy disk images). After booting into the CD boot menu with grub, it can boot into the DOS toolbox and use it normally; but when booting from the Hongye tool disk or XP installation disk menu, a blue screen appears. It is specifically manifested that a blue screen appears after entering the Windows scroll bar or the hard disk detection of the XP installation program.

My computer has 768M of memory.

I used the new version to boot a Linux CD image booted by GNU GRUB, but it couldn't boot and froze! Also, the previous version could boot ISOLINUX.BIN, but now it doesn't work either. So depressed……

VM test without --mem gets error code 60. The following are all tests using --mem:
Maotao 911PE (maotao_BootCD_070911.ISO), Xiaoyi PE (PE20070728.iso), Ashram_PE_Zero.iso (error code 11 when there are spaces, use underscore instead) succeed.
The most handsome reboot (REBOOT.ISO), RecoveryWare (mkrec.iso) fail, error code 25: disk read error.
When loading GEEXBOX image, VM gets error: "Virtual machine kernel stack fault (hardware reset)". When loading DSL image, vm gets error: "Internal monitor error".
Temporarily the test is here, start the real machine test…………(I treat the USB flash drive as the hard disk direct reading method of the virtual machine for testing, which should be close to the real machine?)

dsl4.0rc4: with --mem it restarts automatically, without --mem error code 60;
cdlinux: with --mem, it gets stuck when showing "loading stage2...................", without --mem error code 60;
GEEXBOX, with --mem restarts automatically, without --mem, it shows "ISOlinux 3.20 0x45e72bc3 isolinux :Disk error 04, AX=4200,drive A0"
"Boot failed, press a key to retry..." restarts after pressing the key.
Real machine memory is 2G, VM memory is set to 512M

When loading the Windows installation disc, it can start, and after entering the installation interface, it has a 07b blue screen. When loading the ghostxp image, the boot interface can be seen, and after selecting to enter the disc directory, it prompts "The specified drive is illegal"
If it can't load Windows and Linux, then what's the use of this?

[ Last edited by citydream on 2007-11-18 at 11:14 PM ]

07b blue screen, I've seen many such reports before. Suspected to be caused by the security protection of the Microsoft operating system.

Microsoft finds that the installation media is not on a physical CD, and it may crash and exit. We probably have no countermeasures for this, unless someone cracks Microsoft, just like RinRin cracked the secret of cmdcons.

I think someone will definitely do this in the future.

Running a non-Microsoft CD should be fine.

====================

Emulation is based on BIOS INT13. So, any attempt to access a virtual CD in protected mode generally fails. Only win9x can access real-mode INT13 devices in protected mode. NT series and Linux currently lack this compatibility function. But Linux is open source, and I believe someone will definitely make Linux (after entering protected mode) able to access real-mode INT13 devices in the future.

Test immediately......

The situation is similar to that of the 8th floor. Booting the XP installation disk has error 60, and booting the erd 07B.

Originally posted by Budian at 2007-11-18 22:53:
Running non-Microsoft CDs, no problem

My test also confirms this

07b blue screen is that the XP installation program cannot find the disk controller. When making an integrated XP CD, if the F6-based controller driver is not integrated, when installing on a motherboard that enables AHCI mode or using a system with RAID, SCSI devices, this error is usually reported. Therefore, according to my understanding, it may be necessary to write a disk controller driver for XP and then integrate it into XP so that the XP installation disk can recognize the GRUB for DOS virtual CD-ROM.

The new version can't boot isolinux?

Forgot to mention two things.

1. The boot CD for Win98 is made in the emulated floppy disk mode of 1.44M. There are many CD-ROM drivers in this 1.44M floppy disk. These driver programs are used to drive the physical CD-ROM, and cannot be used to drive our virtual CD-ROM. So, even if you run the Win98 installation program, a CD-ROM driver is needed. Before, I seem to have searched for the eltorito.sys driver on a certain website, which is estimated to be a bit useful.

2. This time, the ISO emulation can not only simulate the "large sector medium" (i.e., CD-ROM) on the "small sector medium" (i.e., floppy disk, hard disk), but also vice versa, simulate the "small sector medium" (disk) on the "large sector medium" (CD-ROM). That is, completely cross the obstacle of sector size incompatibility. For example, you have a CD-ROM (large sector) that has been recognized by grub4dos as (cd) or (cd0), and there is a 30M floppy disk or hard disk image myimg.img on the CD-ROM, then you can use the map without --mem to simulate the img on the CD-ROM (large sector) as a floppy disk, hard disk (small sector). The previous version could not do this. Previously, only --mem could be used to avoid the trouble of sector size incompatibility (medium heterogeneity). Simulating a CD-ROM (large sector) on a CD-ROM (large sector) should also be fine. For example, there is a myiso.iso file on the CD-ROM (cd), and you can use map to simulate it as another CD-ROM, such as (hd32).