Please enable JavaScript.
Coggle requires JavaScript to display documents.
Section 1-Components of a Computer System - Coggle Diagram
Section 1-Components of a Computer System
Computer Systems
Computers = take data, process it and output it (more efficient than humans)
Computer System:
Hardware and Software
Hardware: Physical stuff (CPU, RAM)
Software: Programs on computer
Embedded systems are computers in a larger system (Dishwasher or fridges)
Cheaper
More efficient
Easier to design
Computers contain components which work together (hardware)
The CPU
CPU is the brain of the computers
Processing speed depends on its properties
3 Main Parts
Arithmetic Logic Unit (ALU)
Does calculations
Performs logic operations (AND, OR, NOT) and binary shifts
Contains accumulator register
Cache
Very fast memory in CPU, faster than RAM but slower than registers
Low capacity and expensive compared to RAM
Stores regularly used data
Control Unit (CU)
Main job is to fetch, decode and execute program instructions
Controls flow of data inside the CPU (registers) and outside the CPU (main memory)
Von Neuman Structure
CU contains PC which holds the memory address of the instruction for each cycle
Registers contain MAR and MDR, MAR holds any memory address the CPU might be about to use while the MDR holds the actual memory address which the CPU is about to use
ALU contains Accumulator which stores results of calculations
Memory holds program instructions or program data
Fetch, Decode, Execute cycle
Fetch, copies memory address from PC to MAR then copies instruction stored in MAR to MDR then increases PC point to be able to be ready for next cycle
Decode, instruction in MDR is decoded by CU then CU prepares for next step via loading values into MDR and MAR
Execute, instruction is performed this could be to load data or write data to the memory
Memory
RAM
When computer boots up, operating system is copied from secondary storage to RAM. And stay there until they are closed
Main memory is where all files and data is stored while being used
Volatile=Temporary and requires power to keep data while Non-Volatile=Non-Temporary and keeps data without power
RAM=Random Access Memory
RAM is high-speed, volatile memory. Slower than cache, faster than secondary storage and can be written into by CPU
ROM
ROM is non-volatile and can only be read by the CPU
ROM=Read Only Memory and tells the computer how to boot up (contains BIOS)
CPU and System Performance
CPU performance depends on clock speed, cores and cache
Clock Speed
Number of instructions carriable out per second
Higher clock speed=More instructions processed per second
CPUs can be overclockable to get more instructions per second but its risky
Number of Cores
Each core in the CPU can process data independently
More cores=Faster it can process a batch of data
Cache Size
Data storage inside CPU, faster than RAM
Larger cache=Faster access to data in CPU
More RAM=Faster and smoother system
GPUs help CPUs process images and may reduce workload from CPU since they provide additional VRAM
Secondary Storage
Primary Storage is memory where CPU can access quickly and is volatile
Secondary Storage is where operating system and system files are stored and is non-volatile
3 Types of Secondary Storage
Optical
Medium capacity
Good durability
Very low cost
Moderate reliability
Solid State
High capacity
High reliability
Very high durability
High cost per Gb
Magnetic
High capacity
Moderate durability
Moderate reliability
Cost cheap per Gb