A flat fee, also referred to as a flat rate or a linear rate, refers to a pricing structure that charges a single fixed fee for a service, regardless of usage.[1] Less commonly, the term may refer to a rate that does not vary with usage or time of use.
Synchronous: interrupt occurs as a result of current process, otherwise asynchronous. User requested: interrupt occurs because of direct result by user task, otherwise coerced. Maskable: if desired the interrupt can be disabled by a user task, otherwise unmasked.
Short for Direct Memory Access, DMA is a feature of some computer bus architectures that allows data to be sent from a storage device to memory without using the CPU. Because DMA frees the processor from involvement in the transfer process, it tends to be faster than PIO mode.