I/o memory map, Table 4 – Dell Latitude CPx J User Manual

Page 153

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NOTE: To view memory allocations in Windows 95 and Windows 98, click the Start button, point to Settings, and click
Control Panel. Double-click the System icon. Click the Device Manager tab, and then double-click Computer.

Table 4. Conventional Memory Map

Address Range

Use

0000h-003FFh

Interrupt vector table

00400h-00FFFF

BIOS data area

00500h-005FFh

MS-DOS® and BASIC work area

00600h-9FBFFh

User memory

Table 5

provides a map of the upper memory area. Some of these addresses are dedicated to various system devices, such as the

system/video basic input/output system (BIOS). Others are available for use by expansion cards and/or an expanded memory
manager (EMM).

When the microprocessor or a program addresses a location within the upper memory area, it is physically addressing a location
within one of these devices.

Table 5. Upper Memory Map

Address Range

Use

0009FC00-0009FFFF

PS/2-mouse data area

000A0000-000BFFFF

Video RAM

000C0000-000CFFFF

Video BIOS

000CC000-000CDFFF

Reserved for PC Card

000F0000-000FFFFF

System BIOS

00100000-03FFFFFF

High memory area

FD000000-FDFFFFFF

Video RAM

FF200000-FF2FFFFF

Video RAM

FFFE0000-FFFFFFFF

BIOS ROM

I/O Memory Map

Table 6

provides a map of memory addresses reserved by the system for peripheral input/output (I/O) devices. Use the information

in Table 6 to determine if the memory address of an external peripheral (such as a PC Card) conflicts with a memory address
reserved by the system.

Check the documentation of the external I/O device to determine its memory address. If there is a conflict with a memory address
reserved by the system, change the address of the device.

NOTE: To view I/O addresses in Windows 95 and Windows 98, click the Start button, point to Settings, and click Control
Panel
. Double-click the System icon. Click the Device Manager tab, and then double-click Computer.

Table 6. I/O Memory Map

Address

Device

0000-001F

DMA controller #1

0020-003F

Interrupt controller #1

0040-005F

System timers

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