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Higher Computing Science > Computer Structure > Flashcards

Flashcards in Computer Structure Deck (15):

What is the control unit?

- Controls the fetching and executing of instructions and controls the flow of data through the processor
- Co ordinates the activities of the other units with the CPU


What are the registers?

- They hold data being processed to and from memory
- Instructions being executed
- addresses to be executed


What does the address bus do?

- Holds the address of memory location being accessed
- The more lines on bus the more locations addressed
- It is one way only


What does the data bus do?

- Carries the data bring processed from processor, memory and other devises
- Each line carries 1 but therefore the more lines the more data transferred at the same time
- Two way data transfer between processor and memory


What does the control bus do?

Made up of separate lines each with own functions e.g - clock, interrupt, reset, read, write


Describe the fetch execute cycle.

1. Instruction fetched from memory
2. Decoded and executed
3. Next instruction fetched from memory
4. Decoded and executed


Describe read from memory.

1. Processor sets up address bus with address of location to be accessed
2. Processor activated read line on control bus
3. Memory releases data from specified location onto data bus


Describe write to memory.

1. Processor sets up address bus with address of location to be accessed
2. Processor sets up data bus with data to be written
3. Processor activated write line on control bus
4. Data on data bus is transferred to appropriate memory location


What is a cache?

An area of memory between processor and main memory, usually small for access and faster access than main memory
Used to improve system performance


What is static RAM?

The access time is faster when retrieving data from cache over RAM


What is an emulator?

- Creates a virtual version of absent hardware
- Uses the software version of absent hardware to let software not designed for the host system run as if it were accessing the absent hardware


What is a virtual machine?

Creates a virtual version of software
Used the hardware on the current system to run software within a virtual operating system


What are cloud advantages?

- Automatic uploading of files when connected to the cloud
- Automatic backup of data without having to create a backup of data without having to create a backup schedule
- Collaboration and file sharing


What are cloud disadvantages?

- Can only access files if internet connection present
- User can lose legal rights to their original material if they store it online
- User has no control over security measures in place to protect their files


What are features of data storage?

Allows users to upload files and access again from any connected internet device
- Vairsble amount