Toshiba 2800-S201 User Manual page 210

If Something Goes Wrong
Resolving a hardware conflict
The device most recently connected to the system is the
one most likely to be causing a hardware conflict.
Resolving hardware conflicts on your own
Computer components need resources to accomplish a
task. A device, such as a disk drive or a modem, needs a
channel to the computer's Central Processing Unit (CPU). It
also needs a direct channel to the computer's memory to
store information as it works. These channels of
communication are commonly referred to as system
resources.
Interrupt Request Channel
The channel to the CPU is called an Interrupt Request
(IRQ) because it interrupts what the processor is doing and
requests some of the processor's time. If two or more
devices use the same IRQ, the processor does not know
which device is asking for attention. This causes a hardware
conflict.
Direct Memory Access
Similarly, the data required by the device is stored in a
specific place or address in memory called the Direct
Memory Access (DMA). The DMA provides a dedicated
channel for adapter cards to bypass the microprocessor
and access memory directly. If two or more devices use the
same DMA, the data required by one device overwrites the
data required by the other, causing a hardware conflict.
Part II: Technical Reference
210