Week 1 Flashcards
What does it mean when binary is described as base 2?
This refers to how there are two base values in this system, 0 and 1.
What values can a bit be?
0 or 1
How many bits are in a byte?
8 bits in 1 byte
What level language are machine languages/code?
Machine language is the lowest level
This is closest to the hardware
What level language are programming languages?
Programming languages are higher level languages.
Have to be translated into the machine language of the particular processor.
What is Von Neumann architecture?
This is a program model that describes the architecture relevant to instruction operation which in turn describes how computers are created.
What architecture does Von Neumann architecture consist of?
- A single, shared memory for programs and data
- A single bus for memory access
- An arithmetic (logic) unit
- A (program) control unit
When was the Von Neumann model first published and by who?
1945
John von Neumann
What are the key elements of Von Neumann architectures?
Data
Instructions (how instructions interact, fetched and executed)
Storage of Binary Bits
In terms of computers, what are instructions?
Instructions are the part of the code that gets executed whenever an application/program/OS is run. They contain an operation called ‘op code’ and addresses/registers.
What are the THREE concepts that underlie Von Neumann Architecture?
- Program instructions and data are stored in a single read/write store (main memory/storage e.g. SSD/HDD)
- The contents of this memory is addressable by memory location, regardless of the type of data contained at the location
- Execution of program instructions occurs sequentially, unless explicitly modified
What are the components of a central processing unit (CPU)?
- Arithmetic Logic Unit (ALU)
2. Control Unit (CU)
What is the Fetch-Decode-Execute Cycle?
- Cycle
- A processor can have several states which include fetch, decode and execute
- Fetch
- CPU takes instructions and data from main memory and stores it in special memory locations (Registers)
- Decode
- CPU interprets instructions that were fetches
- Execute
- The instruction is carried out on the data and any temporary result is stored in a register
What does a PC use to advance through a program?
CPUs use a program counter (PC). This contains the address of the next instruction to be executed from memory.
What are interrupts?
Modern computer systems are interrupt driven
An interrupt is a signal to the processor to suspend its current tasks and deal with whatever caused.