|
|
@@ -1951,8 +1951,8 @@ The first type is when the CPU gives orders to the hardware, the other is when t
|
|
|
The second, called interrupts, is much harder to implement because it has to be dealt with when convenient for the hardware, not the CPU.
|
|
|
Hardware devices typically have a very small amount of RAM, and if you do not read their information when available, it is lost.
|
|
|
|
|
|
-Under Linux, hardware interrupts are called IRQ's (Interrupt ReQuests).
|
|
|
-There are two types of IRQ's, short and long.
|
|
|
+Under Linux, hardware interrupts are called IRQs (Interrupt ReQuests).
|
|
|
+There are two types of IRQs, short and long.
|
|
|
A short IRQ is one which is expected to take a very short period of time, during which the rest of the machine will be blocked and no other interrupts will be handled.
|
|
|
A long IRQ is one which can take longer, and during which other interrupts may occur (but not interrupts from the same device).
|
|
|
If at all possible, it is better to declare an interrupt handler to be long.
|
Cheng-Yang Chou