我和朋友一直在做一个OS项目。我们正在关注此Broken Thorn tutorial。我们正在使用Kali Linux来构建我们的操作系统。目前我们正在使用 QEMU PC仿真器来测试我们的启动加载程序。
这是我们的引导加载程序文件Boot1.asm
;*********************************************
; Boot1.asm
; - A Simple Bootloader
;
; Operating Systems Development Tutorial
;*********************************************
bits 16 ; We are still in 16 bit Real Mode
org 0x7c00 ; We are loaded by BIOS at 0x7C00
start: jmp loader ; jump over OEM block
;*************************************************;
; OEM Parameter block
;*************************************************;
; Error Fix 2 - Removing the ugly TIMES directive -------------------------------------
;; TIMES 0Bh-$+start DB 0 ; The OEM Parameter Block is exactally 3 bytes
; from where we are loaded at. This fills in those
; 3 bytes, along with 8 more. Why?
bpbOEM db "My OS " ; This member must be exactally 8 bytes. It is just
; the name of your OS :) Everything else remains the same.
bpbBytesPerSector: DW 512
bpbSectorsPerCluster: DB 1
bpbReservedSectors: DW 1
bpbNumberOfFATs: DB 2
bpbRootEntries: DW 224
bpbTotalSectors: DW 2880
bpbMedia: DB 0xF0
bpbSectorsPerFAT: DW 9
bpbSectorsPerTrack: DW 18
bpbHeadsPerCylinder: DW 2
bpbHiddenSectors: DD 0
bpbTotalSectorsBig: DD 0
bsDriveNumber: DB 0
bsUnused: DB 0
bsExtBootSignature: DB 0x29
bsSerialNumber: DD 0xa0a1a2a3
bsVolumeLabel: DB "MOS FLOPPY "
bsFileSystem: DB "FAT12 "
msg db "Welcome to My Operating System!", 0 ; the string to print
;***************************************
; Prints a string
; DS=>SI: 0 terminated string
;***************************************
Print:
lodsb ; load next byte from string from SI to AL
or al, al ; Does AL=0?
jz PrintDone ; Yep, null terminator found-bail out
mov ah, 0eh ; Nope-Print the character
int 10h
jmp Print ; Repeat until null terminator found
PrintDone:
ret ; we are done, so return
;*************************************************;
; Bootloader Entry Point
;*************************************************;
loader:
xor ax, ax ; Setup segments to insure they are 0. Remember that
mov ds, ax ; we have ORG 0x7c00. This means all addresses are based
mov es, ax ; from 0x7c00:0. Because the data segments are within the same
; code segment, null em.
mov si, msg ; our message to print
call Print ; call our print function
xor ax, ax ; clear ax
int 0x12 ; get the amount of KB from the BIOS
cli ; Clear all Interrupts
hlt ; halt the system
times 510 - ($-$$) db 0 ; We have to be 512 bytes. Clear the rest of the bytes with 0
dw 0xAA55 ; Boot Signiture
要编译我们的引导加载程序并使用 QEMU 进行测试，我们使用以下命令：
nasm -f bin -o Boot1.bin Boot1.asm
dd if=Boot1.bin of=floppyImage.flp bs=512 count=1
qemu-system-x86_64 floppyImage.flp
我们希望使用我们的笔式驱动器在真正的PC上测试上述代码。我们有一台旧的无用的台式电脑，一直在收集灰尘。我们该怎么做呢？我们尝试将dd命令更改为以下内容：
dd if=Boot1.bin of=/dev/sdc1 bs=512 count=1
不幸的是，这失败了。
有什么问题，我们如何解决这个问题？
答案 0 :(得分：-1)
为了将来的参考，我回答了我自己的问题：
;*********************************************
; Boot1.asm
; - A Simple Bootloader
;
; Operating Systems Development Tutorial
;*********************************************
bits 16 ; We are still in 16 bit Real Mode
org 0x7c00 ; We are loaded by BIOS at 0x7C00
jmp start ;FAT file system boot loader should start with a valid x86 instruction.
;It is Generally a JUMP instruction at offset 0x00 and acquires 3 bytes.
;or a JUMP SHORT followed by a NOP.
start: jmp loader ; jump over OEM block
;*************************************************;
; OEM Parameter block
;*************************************************;
; Error Fix 2 - Removing the ugly TIMES directive -------------------------------------
;; TIMES 0Bh-$+start DB 0 ; The OEM Parameter Block is exactally 3 bytes
; from where we are loaded at. This fills in those
; 3 bytes, along with 8 more. Why?
bpbOEM db "My OS " ; This member must be exactally 8 bytes. It is just
; the name of your OS :) Everything else remains the same.
bpbBytesPerSector: DW 512
bpbSectorsPerCluster: DB 1
bpbReservedSectors: DW 1
bpbNumberOfFATs: DB 2
bpbRootEntries: DW 224
bpbTotalSectors: DW 2880
bpbMedia: DB 0xF0
bpbSectorsPerFAT: DW 9
bpbSectorsPerTrack: DW 18
bpbHeadsPerCylinder: DW 2
bpbHiddenSectors: DD 0
bpbTotalSectorsBig: DD 0
bsDriveNumber: DB 0
bsUnused: DB 0
bsExtBootSignature: DB 0x29
bsSerialNumber: DD 0xa0a1a2a3
bsVolumeLabel: DB "MOS FLOPPY "
bsFileSystem: DB "FAT12 "
msg db "Welcome to My Operating System!", 0 ; the string to print
;***************************************
; Prints a string
; DS=>SI: 0 terminated string
;***************************************
Print:
lodsb ; load next byte from string from SI to AL
or al, al ; Does AL=0?
jz PrintDone ; Yep, null terminator found-bail out
mov ah, 0eh ; Nope-Print the character
int 10h
jmp Print ; Repeat until null terminator found
PrintDone:
ret ; we are done, so return
;*************************************************;
; Bootloader Entry Point
;*************************************************;
loader:
xor ax, ax ; Setup segments to insure they are 0. Remember that
mov ds, ax ; we have ORG 0x7c00. This means all addresses are based
mov es, ax ; from 0x7c00:0. Because the data segments are within the same
; code segment, null em.
mov si, msg ; our message to print
call Print ; call our print function
xor ax, ax ; clear ax
int 0x12 ; get the amount of KB from the BIOS
cli ; Clear all Interrupts
hlt ; halt the system
times 510 - ($-$$) db 0 ; We have to be 512 bytes. Clear the rest of the bytes with 0
dw 0xAA55 ; Boot Signiture
以上修改过的代码使用以下dd命令解决了这个问题：
dd if=Boot1.bin of=/dev/sdb1 bs=512 count=1