Memory allocations – Dell Latitude CPi A User Manual
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IRQ4
Available for use by a PC Card unless the built-in serial port or infrared port is configured for COM1 (the default) or
COM3
IRQ5
Generated 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; generated by the video controller
IRQ10
Available for use by a PC Card or audio controller unless the C/Port APR or C/Dock Expansion Station is attached
IRQ11
Generated by USB and PC Card controllers; available for use by a PC Card
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 modular bay to indicate that the drive requires the attention of the
microprocessor
Memory Allocations
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.
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. Select 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
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
000C0000-000CBFFF
Video BIOS
000CC000-000CDFFF
Reserved for PC Card