BIOS基本概念和架构.pptVIP

訓練課程 學習BIOS基本概念和架構 簡介 1. BIOS定義 2. BIOS作用 3. BIOS開機時簡易流程圖 3. BIOS/CMOS設置 4. POST CODE 5. BIOS接手控制權原理 6. 系統Memory address map 1.BIOS定義 Basic Input/Output System縮寫. A Firmware program存儲在ROM or EPROM or FlashROM內存中,提供最基本的硬件初始化(initialize) and 外圍控制的必要程序代碼.通常使用匯編語言編寫. Question: What is the BIOS? The BIOS on a PC is often referred to as FIRMWARE, which is software that is programmed onto a Read Only Memory (ROM) chip. The function of the BIOS is to initialize the motherboard hardware and other peripherals, and loading the operating system. Many of the Plug-n- Play and Power Management functions are handled by the BIOS. The BIOS has specific functions, often referred to as BIOS I/O functions“ or calls, which the operating system and application software uses to carry out tasks or get information on system resources. The BIOS then communicates directly with the hardware to carry out the functions. This is how the BIOS isolates the details of a particular hardware implementation from the operating system or application software. The BIOS is very specifically designed to the hardware platform. A BIOS designed for one system generally will not operate properly (if at all) on another system unless the two systems are identical in design. Simply put, the BIOS is like a fingerprint. ROM種類 1. PROM (Programmable ROM) 可編程存儲器,出廠時每個字節數據都是FF,可以用燒寫器將數據寫入,只能寫入一次. 2. Mask ROM 出廠時就已經有特定的程序/數據碼,內容無法自行修改或燒寫. 3. EPROM (Erasable PROM) PROM的改良,使用貲外線照射後所有字節恢復成FF.用戶可以重新燒寫新的程序/數據碼. 4. Flash ROM 快速只讀存儲器,是當今最當紅的內存種類. Flash ROM 1.先前寫入的數據無法被擦除or破壞,即時關掉電源之後內容仍舊存在.這一定是ROM的特性. 2.不過在特殊工具程序的配合以及相關硬件的設置在某種特定電壓之下,內部存儲的程序代碼/數據可以被擦除,並且可以重新修改寫入新版本的程序/數據. 3.讀取的最小單位是一個byte,但擦除/寫入的單位是以一個block,區塊的大小從4K,8K到16K不等. BIOS的工作 1. POST(Power On SelfTest,開機自測試) 開機系統將控制權交給bios時,它會針對CPU各項寄存器,先檢查是否運行正常,接下來檢查頻率發生器and可編程中斷控制器and DMA控制器的狀態. 2. Initial(初始化) 針對動態內存DRAM and 主板芯片組 and 顯卡以及相關外圍的寄存器register做Initialize設置,並檢測是否能夠正常工作. 所謂初始化就是根據芯片組技術文件的規定,做一些寄存器填值/改位的動作. BIOS的工作(續) 3. 紀錄系統的設置值,並且存儲在非揮發性內存(Non-Volatile R