Computer Organisation & Architecture Flashcards
Identify
Contents Of The CPU
- Processor
- Main Memory
- Address, Control & Data Bases
- Input/Output Controllers
Describe
Processor
Made up of control unit, ALU and Registers
Describe
Main Memory
Used to hold temporary instructions and data for manipulation while the system is running. when held in memory, data is directly accessible by the CPU. Number of memory addresses is decided by width of address bus.
Define
Word
Data
A fixed-sized piece of data handled as a unit by the instruction set or the hardware of the processor. Usually 8, 16, 32 or 64 bits in length.
Describe
Bus
The paths, or lines, on the motherboard on which data, instructions, and electrical power move from component to component. Typically consist of 8, 16, 32 or 64 lines.
Describe
System Bus
Comprised of three separate buses:
* Address bus
* Control bus
* Data bus
Describe
Address Bus
Pathway from memory to processing unit that carries the address in memory to and from which data is transferred.
Identify
Address Bus Connections
- Processor
- Keyboard (Input Controller)
- VDU (Output Controller)
- Disk I/O Controller
- Memory
Describe The Effects Of
Address Bus Width
Determines the maximum number of bits a system can address.
Describe
Data Bus
The lines on the system bus that the CPU uses to send and receive data. It is Bidirectional
Describe The Effects Of
Data Bus Width
Determines the number of bits that can be moved in a single operation. Affects overall system performance
Describe
Control Bus
Carries command and control signals to and from every other component of a computer e.g. read to memory or write to memory.
Identify
Control Signals
- Memory read
- Memory write
- Bus request
- Bus grant
- Clock
Describe
Input/Output Controller
A device that handles the details of input/output and compensates for any speed differences between devices.
Define
Device Driver
Software that directly interacts with the I/O driver e.g. a device driver for a printer.
Describe
Tasks For I/O Controller
Converts the signal received from a peripheral into a format the computer can recognize and manages data flow.
Describe
John Von Neumann Architecture
- CPU performs basic computing operations (add, subtract, etc)
- CPU gets its data from an external memory and writes back results to memory
- Memory is used to hold program instructions which control processing unit and tell it how to manipulate data
- Keeping both data and instructions in memory is the essence the stored-programs architecture
Identify
Use For Von Neumann Architecture
For General Purpose Software
Identify
Issues with Von Neumann
- Shared Memory - Its possible for a defective program to over-write another program in memory, this can crash the program
- Memory Leaks - Program can fail to release memory when finished with it which can result in there being insufficient memory available for other programs which could cause them to crash
- Databus Speed - CPU runs faster than the transfer speed of the data bus, CPU spends more time waiting for data and instructions to arrive from memory. Known as “Von Neumann bottleneck”
Describe
Harvard Architecture
- Data and instructions stored at two physically different memories
- Allows some systems to have a read only instruction memory and read/write data memory
- If system has more instructions than data, then wider address bus can be used for instruction memory, less wide for data memory
- Can be faster than alternative architecture because data and instructions can be fetched simultaneously
Describe
Digital Signal Processing (DSP)
Takes continuous real world data such as audio or video data and compresses it to enable faster processing. It used for mobile phones due to its lower power requirements.
Define
Logic Gates
Devices that produce a single binary output based on one or more binary inputs.
Describe
AND Gate
If both inputs are 1 then the ouput is 1. Otherwise the ouput is 0.
Describe
NOT Gate
If the input is 0, the ouput is 1. If the input is 1, the output is 0.
