Computer Hardware Flashcards
This processor is also often called the brain of computer.
It also has a SET OF REGISTERS which are temporary storage areas for holding data, and instructions.
It executes the stored program instructions, i.e. instructions and data are stored in memory before execution.
Central Processing Unit (CPU)
It performs the arithmetic and logic operations on the data that is made available to it.
Arithmetic Logic Unit (ALU)
It is responsible for organizing the processing of data and instructions. It acts as a supervisor and, controls and coordinates the activity of the other units of computer.
It coordinates the input and output devices of a computer.
The function of a — can be considered synonymous with that of a conductor of an orchestra
Control Unit (CU)
The CPU is fabricated as a ______ ______ ______ chip, and is also known as the ________.
single Integrated Circuit (IC); microprocessor
It is plugged into the motherboard of the computer.
Microprocessor
It is a circuit board that has electronic circuit etched on it and connects the microprocessor with the other hardware components
Motherboard
Performs arithmetic operations on the data that is made available to it. Some of the arithmetic operations supported by the arithmetic unit are—addition, subtraction, multiplication and division.
Arithmetic Unit
It is responsible for performing logic operations. It performs comparisons of numbers, letters and special characters. Logic operations include testing for greater than, less than or equal to condition.
Logic Unit
Are high-speed storage areas within the CPU, but have the least storage capacity.
Are not referenced by their address, but are directly accessed and manipulated by the CPU during instruction execution.
Registers
Important Registers in CPU
Accumulator (ACC)
Instruction Register (IR)
Program Counter (PC)
Memory Address Register (MAR)
Memory Buffer Register (MBR)
Data Register (DR)
It stores the result of arithmetic and logic operations.
Accumulator (ACC)
It contains the current instruction most recently fetched.
Instruction Register (IR)
It contains the address of next instruction to be processed.
Program Counter (PC)
It contains the address of next location in the memory to be accessed.
Memory Address Register (MAR)
It temporarily stores data from memory or the data to be sent to memory.
Memory Buffer Register (MBR)
It stores the operands and any other data
Data Register (DR)
It indicates the amount of data with which the computer can work at any given time.
Size of Register or Word Size
The size of a register may be:
8, 16, 32 or 64 bits
It consists of cache memory and primary memory.
Memory Unit
It is used to store the data and instructions during the processing of data.
Primary Memory or Main Memory
Primary Memory is of two kinds:
Random Access Memory (RAM) Read Only Memory (ROM)
- Volatile.
- It stores data when the computer is on.
- Temporary storage for data and instructions.
- Provides a limited storage capacity, due to its high cost
- It is used to store the data and instructions during EXECUTION of the instructions.
RAM
- Non-volatile memory.
- Used for storing standard processing programs that permanently reside in the computer.
- Programmed by the manufacturer.
ROM
- Non-volatile and is used for permanent storage of data and programs.
- Has a high storage capacity
- Cheaper
Secondary Memory
The data and instructions that are required during the processing of data are brought from the secondary storage devices and stored in the RAM.
It is a very high speed memory placed in between RAM and CPU.
It is a storage buffer that stores the data that is used more often, temporarily, andmakes them available to CPU at a fast rate.
Cache Memory
A computer program is a set of instructions that describe the steps to be performed for carrying out a computational task.
Instruction Format
The program and the data, on which the program operates, are stored in main memory, waiting to be processed by the processor.
Stored Program Concept
An instruction is divided into groups called
Fields
The common fields of an instructionare—
Operation (op) code and Operand code
It represents action that the processor must execute. It tells the processor what basic operations to perform.
Operation (op) code
It defines the parameters of the action and depends on the operation. It specifies the locations of the data
Operand code
A processor has a set of instructions that it understands.
It is the set of all the basic operations that a processor can accomplish
Instruction Set
It is the processor design technique used for implementing the Instruction Set.
Microarchitecture
The primary responsibility of a computer processor is to execute a sequential set of instructions that constitute a program.
Instruction Cycle
The processor fetches the instruction from the memory.
The fetched instruction is placed in the Instruction Register.
Program Counter holds the address of next instruction to be fetched and is incremented after each fetch.
Fetching
The instruction that is fetched is broken down into parts or decoded.
The instruction is translated into commands so that they correspond to those in the CPU’s instruction set.
Decoding
The decoded instruction or the command is executed. CPU performs the operation implied by the program instruction.
Executing
CPU writes back the results of execution, to the computer’s memory.
Storing
A instruction cycle involves four steps:
Fetching
Decoding
Executing
Storing
Some categories of instructions are:
Memory access or transfer of data between registers
Arithmetic operations
Logic operations
Control the sequence, conditional connections, etc
A processor’s instruction set is a determining factor in its architecture.
Microprocessor
Microprocessors are classified as:
Reduced Instruction Set Computer (RISC)
Complex Instruction Set Computer (CISC)
Hardwires the processor with complex instructions, which are difficult to create otherwise using basic instructions.
Combines the different instructions into one single CPU.
Complex Instruction Set Computer (CISC)
Has simple, single-cycle instructions, which performs only basic instructions.
Does not have hardwired advanced functions.
All high-level language support is done in the software.
Reduced Instruction Set Computer (RISC)
Improves instruction execution speed by putting the execution steps into parallel.
A CPU can receive a single instruction, begin executing it, and receive another instruction before it has completed the first.
This allows for more instructions to be performed, about one instruction per clock cycle.
Pipelining
The simultaneous execution of instructions from the same program on different processors.
A program is divided into multiple processes that are handled in parallel in order to reduce execution time.
Parallel Processing
