Making a Single-boot CD-ROM 2 - China DOS Union Forum - China DOS Union

The Booting Catalog of a single - boot CD has 2 parts, one is the Validation Entry and the other is the Initial/Default Entry.

The meaning of each byte of the Validation Entry is as follows

The meaning of each byte of the Initial/Default Entry is as follows

Specifically to this disc, the Booting Catalog is as follows

From 01.....55 AA is the Validation Entry
From 88 03 onwards are 2 lines of the Initial/Default Entry
According to the meaning of each byte of the Validation Entry and the meaning of each byte of the Initial/Default Entry above, it can be seen that this Booting Catalog is set as
1. The boot image of the 80X86 platform (the second byte of the Validation Entry is 00)
2. It is a 2.88M floppy disk image (the second byte of the Initial/Default Entry is 03)
3. The LBA address of this 2.88M floppy disk is 17. 17 is in hexadecimal. Converting it to decimal is 23. (2048 * 23 = 47104 is the physical address of this 2.88M file in the CD)

The 9th byte in the Initial/Default Entry, which is the position where 17 is written above, is written according to the actual LBA address where the disk image is stored.

The method to obtain the LBA of the disk image
In the first step of creating the ISO, that disk image must have a name, for example, boot288.img. After opening the created ISO image with a hexadecimal editor, search for the ASCII code of boot288. After finding it, place the cursor on the first letter in the ASCII area, move up 2 lines, and then move right once. At this time, the information in the hexadecimal area where the cursor is located is the LBA address of this image. Write this address into the 9th byte of the Initial/Default Entry.

After modifying the above Boot Record Volume, Validation Entry, and Initial/Default Entry according to your actual situation, save the file. This single - boot CD image is ready.

Floor1　nre	Posted 2003-01-19 00:00
银牌会员　Posts 361　Credits 1,210
The Booting Catalog of a single - boot CD has 2 parts, one is the Validation Entry and the other is the Initial/Default Entry. The meaning of each byte of the Validation Entry is as follows The meaning of each byte of the Initial/Default Entry is as follows Specifically to this disc, the Booting Catalog is as follows From 01.....55 AA is the Validation Entry From 88 03 onwards are 2 lines of the Initial/Default Entry According to the meaning of each byte of the Validation Entry and the meaning of each byte of the Initial/Default Entry above, it can be seen that this Booting Catalog is set as 1. The boot image of the 80X86 platform (the second byte of the Validation Entry is 00) 2. It is a 2.88M floppy disk image (the second byte of the Initial/Default Entry is 03) 3. The LBA address of this 2.88M floppy disk is 17. 17 is in hexadecimal. Converting it to decimal is 23. (2048 * 23 = 47104 is the physical address of this 2.88M file in the CD) The 9th byte in the Initial/Default Entry, which is the position where 17 is written above, is written according to the actual LBA address where the disk image is stored. The method to obtain the LBA of the disk image In the first step of creating the ISO, that disk image must have a name, for example, boot288.img. After opening the created ISO image with a hexadecimal editor, search for the ASCII code of boot288. After finding it, place the cursor on the first letter in the ASCII area, move up 2 lines, and then move right once. At this time, the information in the hexadecimal area where the cursor is located is the LBA address of this image. Write this address into the 9th byte of the Initial/Default Entry. After modifying the above Boot Record Volume, Validation Entry, and Initial/Default Entry according to your actual situation, save the file. This single - boot CD image is ready.