01 Section 1 - Computer Systems and the CPU Flashcards
What is a computer?
A computer is a machine that processes data
What is the purpose of a computer?
To take data in, process it and then output it
What does a computer system consist of?
Hardware and software
What is hardware? (and what are some examples)
Hardware is the physical stuff that makes up a computer
CPU, Motherboard, Monitor, Printer
What is software? (and what are some examples)
Software is the programs or applications that a computer system runs
(an operating system, a word processor, video game)
What are external pieces of hardware called?
Peripherals
They are external pieces of hardware like the keyboard, mouse and printers.
What are embedded systems?
Embedded systems are computers built into other devices
they are dedicated to a single task
What are some examples of embedded systems?
Dishwashers
Washing machine
Microwaves
Central heating systems
What are embedded systems often used as?
Embedded systems are often used as control systems, they monitor and control machinery in order to achieve a desired result
What are the main hardware components of a computer?
Power supply Case cooling fan CPU heat sink and cooling fan CPU Graphics Card Motherboard Hard Disc Drive RAM sticks Ghost Optical drive
What is the motherboard?
The main circuit board in the computer, where the hardware is connected
What does CPU stand for?
Central Processing Unit
What is the CPU?
It’s the brain of a computer system
-it processes data and instructions that make the system work
What does the CPU architecture describe?
- the main components of the CPU
- how the components interact with each other
- how the components interacts with other parts of the computer system
What are the two main types of architecture?
Von Neumann
Harvard
What does CU stand for?
Control Unit
What does ALU stand for?
Arithmetic Logic Unit
What does PC stand for?
Program Counter
What does MAR stand for?
Memory Address Register
What does MDR stand for?
Memory Data Register
What does ACC stand for?
Accumulator
What are the three buses between the CPU and RAM?
Address bus
Control bus
Data bus
What is the CU?
The CU is in overall control of the CPU.
-job is to execute program instructions by following the fetch-decode-execute cycle
What does the ALU do?
All the calculations
-operations, comparisons, logic operations and binary shifts
What is cache?
Cache is very fast memory in the CPU (slower than the registers, but quicker than RAM)
What does cache store?
Regularly used memory, the CPU goes to cache first to look for data and then RAM if it can’t find it in cache
What are the features of cache memory?
very low capacity
expensive
What does the Program counter do?
holds the memory address of the instructions for each cycle
What does the ACC do?
stores intermediate results of calculations in the ALU
What does the MAR do?
holds any memory address about to be used by the CPU
-the address might point to data or a CPU instruction
What does the MDR do?
holds the actual data or instruction
-this may have been fetched from memory or might be waiting to be written to memory
What is in the Fetch process from the Fetch- Decode- Execute cycle?
- copy the memory address from the PC to the MAR
- carry out address location in memory from the MAR down the address bus and back out the data bus to the MDR
- copy data in MDR to the CIR
- increment in PC(ready for the next cycle)
What is in the Decode process from the Fetch- Decode- Execute cycle?
- the instruction in the MDR is decoded by the CU
- the CU then prepares for the next step
What does CIR stand for?
Current Instruction Register
What is in the Execute process from the Fetch-Decode- Execute cycle?
-the instruction is performed
this could be load, write, do a calculation, logic operation, change the address in the PC, halt the program
What are the registers in the CPU?
PC
MAR
MDR
CIR
What are registers?
They are on the CPU and temporarily hold tiny bits of data needed by the CPU.
-they are super-quick to read/write to
