Topic 2: Computer Architecture
Central Processing Unit(CPU): a hardware component of a computer system and can
perform basic arithmetic, logical or input/output operations, in order to process data
from input devices into useful information
CPU consists of:
Control Unit(CU): controls the retrieval of instructions from the primary memory as
well as the sequence of their execution; provides the ALU with the data that needs
to be processed as well as the instructions of how the data should be processed
Arithmetic Logic Unit(ALU): performs all the basic arithmetic, logical or
input/output operations.
Memory Address Register(MAR): holds the memory address of the data to be
used by the ALU, so that the ALU can fetch the corresponding content from the
memory and process it accordingly; holds the memory address of where data that
has been processed will need to be stored
Memory Address Bus(MAB): MAR communicates with primary memory through
MAB, a connecting wire
Memory Data Register(MDR): holds the data that is to be used by the ALU and
then saved to the RAM; after the processing has taken place, the ALU places the
result data onto the MDR
Memory Data Bus(MDB): MDR communicates with primary memory through MAB,
a connecting wire
Primary Memory: the component of a computer system, which stores data that CPU
accesses directly
Random Access Memory(RAM): a general-purpose storage area meaning that the
data stored can be overwritten
stores executing data and instructions of program currently being run;
Topic 2: Computer Architecture 1
, data stored can be overwritten(changed)
volatile: whenever power is lost the contents of its memory are wiped
Dynamic RAM(DRAM): slower than SRAM, but preferred for the main RAM of a
computer system
Static RAM(SRAM): faster than DRAM; more expensive;
Cache Memory
a small amount of SRAM placed between the main RAM and the CPU
temporarily stores instructions and data so that the processor does not need to
access the slower main memory(DRAM)
holds the information from the RAM that is most actively used, and accessed
most frequently
computer system will run faster as the slower main memory will need to be
accessed less frequently
Read Only Memory(ROM)
store instructions and data and cannot be overwritten
non-volatile: whenever power is lost the instructions that are embedded in ROM
cannot be changed
used to store programs and instructions that do not need to be updated or
change(e.g. BIOS)
Topic 2: Computer Architecture 2
Central Processing Unit(CPU): a hardware component of a computer system and can
perform basic arithmetic, logical or input/output operations, in order to process data
from input devices into useful information
CPU consists of:
Control Unit(CU): controls the retrieval of instructions from the primary memory as
well as the sequence of their execution; provides the ALU with the data that needs
to be processed as well as the instructions of how the data should be processed
Arithmetic Logic Unit(ALU): performs all the basic arithmetic, logical or
input/output operations.
Memory Address Register(MAR): holds the memory address of the data to be
used by the ALU, so that the ALU can fetch the corresponding content from the
memory and process it accordingly; holds the memory address of where data that
has been processed will need to be stored
Memory Address Bus(MAB): MAR communicates with primary memory through
MAB, a connecting wire
Memory Data Register(MDR): holds the data that is to be used by the ALU and
then saved to the RAM; after the processing has taken place, the ALU places the
result data onto the MDR
Memory Data Bus(MDB): MDR communicates with primary memory through MAB,
a connecting wire
Primary Memory: the component of a computer system, which stores data that CPU
accesses directly
Random Access Memory(RAM): a general-purpose storage area meaning that the
data stored can be overwritten
stores executing data and instructions of program currently being run;
Topic 2: Computer Architecture 1
, data stored can be overwritten(changed)
volatile: whenever power is lost the contents of its memory are wiped
Dynamic RAM(DRAM): slower than SRAM, but preferred for the main RAM of a
computer system
Static RAM(SRAM): faster than DRAM; more expensive;
Cache Memory
a small amount of SRAM placed between the main RAM and the CPU
temporarily stores instructions and data so that the processor does not need to
access the slower main memory(DRAM)
holds the information from the RAM that is most actively used, and accessed
most frequently
computer system will run faster as the slower main memory will need to be
accessed less frequently
Read Only Memory(ROM)
store instructions and data and cannot be overwritten
non-volatile: whenever power is lost the instructions that are embedded in ROM
cannot be changed
used to store programs and instructions that do not need to be updated or
change(e.g. BIOS)
Topic 2: Computer Architecture 2
