Dell Latitude CSx H - Manual (Page 36)

Table 3. IRQ Line Assignments
Memory Allocations
Table 4 provides a map of the conventional memory area. When the microprocessor or a program addresses a location within the conventional
memory range, it is physically addressing a location in main memory.
Table 4. Conventional Memory Map
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
NOTES: Installed devices cannot share the same COM port address. The default address of your computer's serial port is COM1.
To view IRQ line assignments in the Microsoft® Windows® 95 and Windows 98 operating systems, click the Start button, point to
Settings, and click Control Panel. Double-click the System icon. Select the Device Manager tab, and then double-click Computer.
IRQ Line Reserved/Available
IRQ0 Reserved; generated by the system timer
IRQ1 Reserved; generated by the keyboard controller to signal that the keyboard output buffer is full
IRQ2 Reserved; generated internally by the interrupt controller to enable IRQ8 through IRQ15
IRQ3 Available for use by a PC Card unless the integrated serial port or infrared port is configured for COM2 or COM4
IRQ4 Available for use by a PC Card unless the integrated serial port or infrared port is configured for COM1 (the default) or COM3
IRQ5 Available for use by the audio controller
IRQ6 Generated by the diskette drive controller to indicate that the diskette drive requires the attention of the microprocessor
IRQ7 Available for use by a PC Card or audio controller if the parallel port is disabled
IRQ8 Reserved; generated by the system I/O controller's RTC
IRQ9 Reserved
IRQ10 Available for use by a PC Card or audio controller unless the C/Port Family APR or C/Dock Family Expansion Station is attached
IRQ11 Available for use by USB, PC Card, video controller, and audio controller
IRQ12 Reserved; generated by the keyboard controller to indicate that the output buffer of the touch pad or external PS/2 mouse is full
IRQ13 Reserved; generated by the math coprocessor
IRQ14 Reserved; generated by the hard-disk drive to indicate that the drive requires the attention of the microprocessor
IRQ15 Reserved; generated by CD-ROM drive in the external media bay to indicate that the drive requires the attention of the
microprocessor
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.
Address Range Use
0000h-003FFh Interrupt vector table
00400h-004FFh BIOS data area
00500h-005FFh MS-DOS ® and BASIC work area
00600h-9FBFFh User memory
Address Range Use
0009FC00-0009FFFF PS/2-mouse data area
000A0000-000BFFFF Video RAM
000C0000-000CBFFF Video BIOS
000CC000-000CDFFF PC Card
000F0000-000FFFFF System BIOS