FAT文件系统原理

计算机在按下power键以后，开始执行主板bios程序。进行完一系列检测和配置以后。开始按bios中设定的系统引导顺序引导系统。假定现在是硬盘。Bios执行完自己的程序后如何把执行权交给硬盘呢。交给硬盘后又执行存储在哪里的程序呢。其实，称为mbr的一段代码起着举足轻重的作用。MBR(master boot record),即主引导记录，有时也称主引导扇区。位于整个硬盘的0柱面0磁头1扇区(可以看作是硬盘的第一个扇区)，bios在执行自己固有的程序以后就会jump到mbr中的第一条指令。将系统的控制权交由mbr来执行。在总共512byte的主引导记录中，MBR的引导程序占了其中的前446个字节(偏移0H~偏移1BDH)，随后的64个字节(偏移1BEH~偏移1FDH)为DPT(Disk PartitionTable，硬盘分区表)，最后的两个字节“55 AA”(偏移1FEH~偏移1FFH)是分区有效结束标志。-FAT file system in principle computer keys after pressing the power to start procedures for the implementation of motherboard bios. End conducted a series of inspections and subsequent distribution. Start by bios set in the boot sequence guidance system. It is assumed that drive. Bios implementation End after their own procedures on how the implementation of the right to drive it. Then drive to the store where the implementation of the procedure beforehand. In fact, as mbr section of the code will play a decisive role. MBR (master boot record), the master boot record that is sometimes also called master boot. Located in the entire drive 0 0 cylinder head a sector (can be seen as one drives the sector), bios their inherent in the implementation of the procedures will jump to the future mbr