Arithmetic and Logic Unit - does all mathematical calculations and makes all logical decisions
The control unit fetches instruction into the registers from cache/memory, decodes the instruction and executes it. The control unit oversees the machine cycle.
temporary storage areas within the processor that are used to hold data that has been fetched from memory or produced during a calculation
a set of bi-directional lines that carry data to and from the processor registers / cache and main memory locations. Number of lines usually matches the processor / memory word size.
Used by processor for read/write operation to identify memory storage locaction. It is unidirectional. The number of lines determines the number of storage locations.
This is made up from a number of independent lines. Includes; read, write, clock, interrupt, non-maskable interrupt and reset.
generates a constant pulse used to synchronize operations in the computer
returns system to its initial state stopping all processes clears all registers and RAM
informs the processor that an external event has occurred, current task is suspended, interrupt is serviced, original task resumes
Fetching instructions from main memory, decode and execute instruction, repeat until HALT is encountered. Requires data/address/control busses for memory read.
Special purpose register. Contains the data to be written to memory or receives the data read from memory via data bus.
Memory Address Register
An special purpose register of the CPU that is used to identify the address of a location in main memory via the address bus.
A special data storage area used only by the processor, located close to the processor, faster access than main memory, though smaller capacity.
from top of hierarchy to bottom:
decreasing cost per bit, increasing capacity, increasing access time, decreasing frequency of access to the memory by the processor
Memory is split in storage locations. Each location has its own unique binary address. Increasing number of locations requires more address bits.
millions of instructions per second, a measure of machine cycle time
Floating point operations per second. the number of mathmatical calculations. GOOD- instructions tend to be the same complexity across different processors
application benchmark test
compare computer systems performance operating under the same conditions involving common user software tasks eg database sort
data bus width
number of lines on the data bus that determines the word size, larger width transfers more data per cycle, improves throughput
larger cache reduces access to slower main memory but raises expense
data transfer rate
the number of bits per second at which data is transferred between CPU and peripheral interface, factor in overall performance