Technical Information 1-11System and Video BIOSThe system and video BIOS are stored in a 1 MB (128 KB by 8) flash memory device(Flash ROM). The system BIOS uses 64 KB, the video BIOS uses 32 KB, and 32 KB isreserved. The system BIOS is capable of being shadowed and cached through the system’sSetup utility (see Section 2, “Setup and Operation,” for setup information). The SystemBIOS is write protected and automatically enabled.The BIOS programs execute the Power-On Self-Test, initialize processor controllers, andinteract with the display, diskette drives, hard disk drives, communication devices, andperipherals. The system BIOS also contains the Setup utility. The hardware setup defaultcopies the ROM BIOS into RAM (shadowing) for maximum performance.The Flash ROM allows the system and video BIOS to be upgraded with the BIOS Updateutility, without removing the ROM (see Section 2 for further information on the BIOSUpdate utility). The Flash ROM supports the reprogramming of the system BIOS and thevideo BIOS.The system memory map is shown in Table 1-4.Table 1-4 System Memory MapMemory Space Size Function00000000-0007FFFF 512 KB MS-DOS applications (always Cacheable, noread/write protect)00080000-0009FFFF 128 KB Optional memory space gap (MS-DOSapplications)000A0000-000BFFFF 128 KB Video Buffer (SMM space, non-cacheable)000C0000-000C7FFF 32 KB Video BIOS (shadowed in DRAM)000C8000-000DFFFF 160 KB Expansion (shadowed in DRAM)000E0000-000FFFFF 64 MB System BIOS (shadowed in DRAM)00100000-00EFFFFF 14 MB Cacheable00F00000-00FFFFFF 1 MB Optional memory space gap01000000-03FFFFFF 48 MB Always cacheable04000000-07FFFFFF 64 KB L2 Cache (non-cacheable)L1 Cache (Cacheable)FFF80000-FFFFFFFF 512 KB BIOS ROM
