|System call||Volatile & nonvolatile|
|Seek time||Rotational latency|
Dual-mode has two seperatemodes of operation:
- Prevent any user program from directly controlling I/O devices.
- A trap (or an exception) is a software-generated interrupt caused either by an error (for example, division by zero or invalid memory access), or by a specific request from a user program that an operating-system service be performed.
- A request to operating system which is used to allow the user program to wait for I/O completion, if desired. It is also called monitor call, a special operation that is executed by software for triggering an interupt.
- Main memory is a volatile storage device that lose its contents when power is turned off or otherwise lost.
- A memory buffer used to accommodate a speed differential is called a cache.