bootloader

So I want to add padding in the bootsector. Let's say, there is currently just an endless loop in there: jmp . . The sector needs to be 512 bytes long. Also, the magic num 0xaa55 is needed which is added at the end. jmp . .skip 508, 0 .word 0xaa55 But what if I want to print something but don't want to count all the bytes to pad it into the right size? In Intel/NASM syntax would it be: ; print something times 510-($-$$) db 0 dw 0xaa55 But in AT&T syntax? Well a loop ( .rept ) doesn't work here because . doesn't give an absolute value which is needed here. We have the same problem with .skip /

I am working on writing my own operating system. So far, my code exceeds 512 bytes, which is too large to fit in a simple boot sector. I understand that I now have to write a bootloader that reads arbitrary code that may or may not be greater than a single 512-byte sector. The bootloader would need to: Function as a boot record with disk signature 0xaa55. Read a second stage (the test code) start from LBA 1 (LBA 0 is boot sector) of arbitrary length starting at memory address 0x7E00. Transfer control to it using a FAR JMP to 0x0000:0x7E00. Be usable as a 1.44 MiB floppy disk image for use in

I changed my bootloader from CHS to LBA, so I replaced int 13h 02h with int 13h 42h . It works correctly in QEMU, however, I have troubles running it with Bochs and my laptop. I wrote bootloader to USB flash drive with dd if=main.bin of=/dev/sdb bs=512 . Laptop loads Intel UNDI and gives me the following error: No bootable device - insert boot disk and press any key . So I tried to debug it with Bochs and noticed that Bochs recognizes this binary file as bootable. However, nothing had been loaded after int 13h executed. Then I tried to load my old PC from this flash drive, and it works! It

1、用shell脚本实现自动登录机器 #!/usr/bin/expect set ip 192.168.2.192 set user root set password root spawn ssh $user@$ip expect { "yes/no" { send "yes\n";exp_cotinue} "password" {send "$password\n"} } interact 2、shell 判断一个值bone是否在数组arrayZ=( one two three four five five )中 #!/bin/bash var=( "one" "two" "three" "four" "five" "five" ) for i in seq $[${#var[*]}-1] ;do echo ${var[$i]} if [ ${var[$i]} == bond ];then echo yes else echo no fi done unset var 3、用命令或者脚本实现 0057AF051EFF 变为 00:57:AF:05:1E:FF a=0057AF051EFF echo ${a:0:2}:${a:2:2}:${a:4:2}:${a:6:2}:${a:8:2}:${a:10:2} 4、a b c d e f g h i j k l m n o p q