Fixed typos and edited wording

Chapter-3/README.md

@@ -8,7 +8,7 @@ The BIOS boot sequence is: RAM detection -> Hardware detection/Initialization ->
 
 The most important step for us is the "Boot sequence", where the BIOS is done with its initialization and tries to transfer control to the next stage of the bootloader process.
 
-During the "Boot sequence", the BIOS will try to determine a "boot device" (e.g. floppy disk, hard-disk, CD, USB flash memory device or network). Our Operating System will initially boot from the hard-disk (but it will be possible to boot it from a CD or a USB flash memory device in future). A device is considered bootable if the bootsector contains the valid signature bytes `0x55` and `0xAA` at offsets 511 and 512 respectively (called the magic bytes of the Master Boot Record, also known as the MBR). This signature is represented (in binary) as 0b1010101001010101. The alternating bit pattern was thought to be a protection against certain failures (drive or controller). If this pattern is garbled or 0x00, the device is not considered bootable.
+During the "Boot sequence", the BIOS will try to determine a "boot device" (e.g. floppy disk, hard-disk, CD, USB flash memory device or network). Our Operating System will initially boot from the hard-disk (but it will be possible to boot it from a CD or a USB flash memory device in the future). A device is considered bootable if the bootsector contains the valid signature bytes `0x55` and `0xAA` at offsets 511 and 512 respectively (called the magic bytes of the Master Boot Record, also known as the MBR). This signature is represented (in binary) as 0b1010101001010101. The alternating bit pattern was thought to be a protection against certain failures (drive or controller). If this pattern is garbled or 0x00, the device is not considered bootable.
 
 BIOS physically searches for a boot device by loading the first 512 bytes from the bootsector of each device into physical memory, starting at the address `0x7C00` (1 KiB below the 32 KiB mark). When the valid signature bytes are detected, BIOS transfers control to the `0x7C00` memory address (via a jump instruction) in order to execute the bootsector code.
 
@@ -29,7 +29,7 @@ To make it simple, GRUB is the first thing booted by the machine (a boot-loader)
 
 #### How to use GRUB?
 
-GRUB uses the Multiboot specification, the executable binary should be 32bits and must contain a special header (multiboot header) in its 8192 first bytes. Our kernel will be a ELF executable file ("Executable and Linkable Format", a common standard file format for executables in most UNIX system).
+GRUB uses the Multiboot specification, the executable binary should be 32bits and must contain a special header (multiboot header) in its first 8192 bytes. Our kernel will be a ELF executable file ("Executable and Linkable Format", a common standard file format for executables in most UNIX system).
 
 The first boot sequence of our kernel is written in Assembly: [start.asm](https://github.com/SamyPesse/How-to-Make-a-Computer-Operating-System/blob/master/src/kernel/arch/x86/start.asm) and we use a linker file to define our executable structure: [linker.ld](https://github.com/SamyPesse/How-to-Make-a-Computer-Operating-System/blob/master/src/kernel/arch/x86/linker.ld).
 
@@ -80,7 +80,7 @@ The first step is to create a hard-disk image (c.img) using qemu-img:
 qemu-img create c.img 2M
 ```
 
-We need now to partition the disk using fdisk:
+Now we need to partition the disk using fdisk:
 
 ```bash
 fdisk ./c.img
@@ -128,7 +128,7 @@ fdisk ./c.img
 > w
 ```
 
-We need now to attach the created partition to the loop-device using losetup. This allows a file to be access like a block device. The offset of the partition is passed as an argument and calculated using: **offset= start_sector * bytes_by_sector**.
+Now we need to attach the created partition to the loop-device using losetup. This allows a file to be access like a block device. The offset of the partition is passed as an argument and calculated using: **offset= start_sector * bytes_by_sector**.
 
 Using ```fdisk -l -u c.img```, you get: 63 * 512 = 32256.
 
@@ -162,7 +162,7 @@ quit
 EOF
 ```
 
-And finally we detach the loop device:
+And finally, detach the loop device:
 
 ```bash
 losetup -d /dev/loop1