Architecture Flashcards
System
combination of connected parts working together to achieve a common goal
Computer system
system involving interaction between hardware, software, data and the user
What is Computer architecture
specification of how a computer’s parts are physically and logically connected
Von Neumann architecture components
-CPU -Memory -Bus -Input/Output devices
What is a CPU
(processor) central processing unit. Carries out computations on data by following instructions
Control Unit
directs operations of CPU. Controls transfer of data and operations between other units of the computer. Instructs memory, logic unit and input and output devices on how to respond to program’s instructions
ALU and what it is
Arithmetic/Logic Unit. Where A and L processing takes place. Receives instructions and data (both from memory) and operates on them
What are Registers
temporary storage locations that can be accessed by CPU quickly when carrying out instructions. Very expensive and have a small capacity.
Examples of registers
- Program Counter: stores memory address of the next instruction to be executed, stores where CPU is in program sequence at any given time and is updated to indicate what must be done next
- Memory Address register [MAR]: store memory addresses of data required to carry out instruction.
Memory
stores data to be operated on + instructions(programs) that operate on data + the results
RAM
Random Access Memory. Temporarily holds data and instructions currently being executed by CPU. Volatile and typically fast.
Volatile memory
when computer loses power the data is lost
ROM
Read Only Memory. holds permanent data and instructions. It can be read from but not written to or modified. Non-volatile and stores firmware such as BIOS.
What is BIOS
Basic Input/Output System. Small amount of ROM for computer startup routine. Performs necessary checks and then hands control to OS
OS
Operating System
Primary Storage
(Main Memory). Memory with information for immediate use by the CPU. E.g. RAM and ROM
Fetch-execute cycle
Happens millions of times per second on modern computers. 1. FETCH. CPU fetch next instruction from memory. 2. Instruction found at memory address in binary code. 3. DECODE Decodes binary and reveals instruction EXECUTE which is executed. 4. Cycle starts again
What is The Clock
generates a continuous stream of electric pulses at a very steady frequency. Fed to all circuits in computer to ensure they operate on instructions together and are perfectly synchronised.
Clock and cpu speed
main factor determining CPU speed. Each pulse means CPU executes one instruction. 5GHz = 5 billion instructions per second
Cores
Part of CPU allowing it to execute instructions simultaneously. 8 cores = 8 instructions during one clock cycle
Bus
allows data and instructions to move from memory to the CPU and vice versa
Input/Output devices examples
-Secondary Storage. -USB devices(keyboards). -Display Devices. Pointing devices(mice)
What is Secondary Storage?
store data persistently. None volatile and an example would be hard drives
Differences between primary and secondary storage
-Primary is for immediate use by CPU whereas Secondary is used anytime.
-Primary is temporary.
-Generally primary is more expensive and smaller