Last Test Term 3 Flashcards
DRAM
- Requires data to be refreshed periodically in order to retain the data
- Needa higher power consumption which is significant when used in battery powered devices
Description three differences between RAM and ROM
- ROM Doesn’t lose contents when powered off
- RAM Stores files currently in use
- RAM has often has larger memory size than ROM
Define Firewall and how it helps with security of data
> Sits between LAN and WAN and permits or blocks traffic to or from the network
> It can be software or hardware and can help to block hacking/viruses
Define Authentication and how it helps with security of data
> Process of identifying if a person or something is who they claim to be
> can be done by log on passwords
Describe two differences between data and integrity
- Security deals with protection of data
- Integrity validates the data
State two ways of maintaining data integrity at the input stage. Use examples to help explain yourself
- Validation, example: range check, type check and length check
- Verification, example: checks if data matches original
State two ways of maintaining data integrity during data transmission. Use examples to explain your answer
- Check sum, add up bites in data being sent and sends check sum with the data, calculations is redone at receivers, if not the same sum then the data has been corrupted
- Parity check, one bit is reserved as a parity bit, 0= odd T the end, parity is checked at receivers end and a change in the parity indicates data corruption
An interrupt is generated by a key on a computer keyboard, Explain how the computer handles this interrupt
> An interrupt flag is raised in the register
At the end or start of the FE cycle
The system checks the interrupt register for higher priority interrupts that than current process
If it is true, it stores the current contexts of the registers on a stack
The appropriate interrupt service routine for the key press is called
