Technical Information 1-7The Flash ROM allows the BIOS to be upgraded with the BIOS Update utility withoutremoving the ROM (see Section 2, Setup and Configuration). The BIOS can only be repro-grammed by powering on the system with the BIOS Update utility diskette in Drive A.The BIOS programs execute the Power-On Self-Test, initialize processor controllers, and inter-act with the display, diskette drives, hard disks, communication devices, and peripherals. Thesystem BIOS also contains the Setup program and provides VGA controller support. The hard-ware setup default copies the ROM BIOS into RAM (shadowing) for maximum performance.System BIOS is located in the upper portion of the Flash ROM and video BIOS in the lowerportion. System BIOS is located between F0000h-FFFFFh and supports shadowing and shad-owed memory. System BIOS is write protected and automatically enabled.Video BIOS is located between C0000h and C7FFFh. If the internal video is disabled, this rangeis mapped to ISA. The system memory map in shown in Table Section 1-2.Table Section 1-2 System Memory MapMemory Space Size Function000000-07FFFF 512 KB Conventional base memory080000-09FBFF 128 KB Extended conventional base memory09FC00-09FFFF 1 KB Extended BIOS Data0A0000-0BFFFF 128 KB On-board video memory0C0000-0C7FFF 32 KB On-board BIOS0C8000-0E7FFF 128 KB Available high DOS memory (open to ISA and PCI bus)0E8000-0ECFFF 20 KB Plug-n-Play ESCD data0ED000-OEDFFF 4 KB Reserved for logo0EE000-0EFFFF 8 MB Flash boot block (available for HIMEM)0F0000-0FFFFF 64 KB System BIOS1000000- On-Board 130 MB Extended and/or Expanded system memoryFlash ROM supports the reprogramming of the system and built-in video BIOS. A jumper on thesystem board enables or disables the BIOS flashing feature. The factory default for the jumper isenabled, allowing the BIOS to be flashed. See Section 2, Setup and Operation, for jumper infor-mation. If the BIOS upgrade is interrupted, see Section 4, Maintenance and Troubleshooting, forinformation on recovering the BIOS if there is a catastrophic failure.
