Technical Reference 
37 
2.1.2  Memory Map 
Table 10 lists the system memory map. 
Table 10.  System Memory Map 
Address Range 
(decimal) 
Address Range 
(hex) 
 
Size 
 
Description 
1024 K - 16777216K K  100000 – 400000000  16382 MB  Extended memory 
960 K - 1024 K  F0000 - FFFFF  64 KB  Runtime BIOS 
896 K - 960 K  E0000 - EFFFF  64 KB  Reserved 
800 K - 896 K  C8000 - DFFFF  96 KB  Potential available high DOS 
memory (open to the PCI bus).  
Dependent on video adapter used. 
640 K - 800 K  A0000 - C7FFF  160 KB  Video memory and BIOS 
639 K - 640 K  9FC00 - 9FFFF  1 KB  Extended BIOS data (movable by 
memory manager software) 
512 K - 639 K  80000 - 9FBFF  127 KB  Extended conventional memory 
0 K - 512 K  00000 - 7FFFF  512 KB  Conventional memory 
2.2  Connectors and Headers 
  CAUTION 
Only the following connectors and headers have overcurrent protection:  back panel 
and front panel USB and PS/2. 
The other internal connectors and headers are not overcurrent protected and should 
connect only to devices inside the computer’s chassis, such as fans and internal 
peripherals.  Do not use these connectors or headers to power devices external to the 
computer’s chassis.  A fault in the load presented by the external devices could cause 
damage to the computer, the power cable, and the external devices themselves. 
Furthermore, improper connection of USB header single wire connectors may 
eventually overload the overcurrent protection and cause damage to the board. 
This section describes the board’s connectors. The connectors can be divided into 
these groups: 
•  Back panel I/O connectors 
•  Component-side I/O connectors and headers (see page 39)