1.2 Memory COMPLETE Flashcards
What does ROM do?
Holds the 1st instructions for the computer to boot up (BIOS).
You can only read this.
What does RAM do?
Holds the instructions of the data, OS and applications currently in use.
You can read and write (edit) the RAM.
Why is RAM volatile?
Everything stored in it is deleted when not connected to a power supply.
Which is bigger: RAM or ROM?
RAM.
Why is RAM faster than a hard drive?
It uses solid state chips.
What happens if the BIOS is written over?
The motherboard won’t work and instructions are lost.
What is virtual memory?
An area on the hard drive that OS transfers the data that is being least used with the currently used data when the RAM is full.
How do you overcome the creation of virtual memory?
Add more RAM.
What is disk thrashing?
When data is frequently swapped between the RAM and virtual memory, causing the programs to slow.
Why don’t applications run on the hard disk?
It’s too slow so data is transferred to the RAM which is faster.
What is flash memory?
Non-volatile drive which can read and write.
E.g. solid-state drive, USB, SD cards.
Why is flash memory more expensive than a hard disk?
Because it’s more portable, durable and reliable due to non-moving parts (less susceptible to damage).
What does RAM stand for?
Random Access Memory
What does RAM do?
Stores data and instructions when an application is running
True/False: Data can be read from and written to RAM
True
Is RAM volatile or non-volatile?
Volatile
What does volatile mean?
If you turn off the power, the data is lost
What does ROM stand for?
Read Only Memory
What does ROM do?
Stores instructions that don’t need to be changed during normal use
What is stored in the ROM?
The BIOS (start up instructions)
True/False: Data can be read from and written to ROM
False, data can only be read from ROM
Is ROM volatile or non-volatile?
Non-volatile
What does non-volatile mean?
It retains data even if the power is turned off
How much RAM would a typical smartphone have?
2GB
How much RAM would a typical games console have?
4GB
How much RAM would a typical laptop have?
8GB
How much RAM would a typical workstation have?
16GB or more
True/False: RAM is often removable
True
True/False: If you buy a computer with 8GB of RAM, you cannot add more
False, you can upgrade many computers by adding more RAM
Why are the startup instructions stored in the ROM?
Because they need to be stored and saved even after the power is turned off - so the computer can start up again when powered on.
Where is virtual memory located?
In the hard disc drive or solid state drive
What is the virtual memory used for?
Temporary RAM when the actual RAM is full. It acts like an overflow for RAM
Where are program instructions and data constantly moving between?
The CPU and the RAM
If many programs are running, RAM may become ____
full
What does the OS do if there is no free RAM?
Swap some of the data stored in RAM to the virtual memory on the hard disc and swap in the requested data into the free area of the RAM
What data is usually swapped out of RAM when?
The least recently used data
What happens if data that has been swapped out from RAM to virtual memory is needed again?
It is swapped back in from virtual memory at the expense of other data
The more RAM a computer has, the ____ virtual memory will be needed
less
Adding more RAM will significantly improve/worsen the performance of a computer
improve
What are the disadvantages of virtual memory?
The read/write speed is much slower than RAM, therefore there will be a significant performance drop if the system has to rely too heavily on virtual memory. Also, disc thrashing can occur
What is disc thrashing?
Programs running more slowly as a result of the OS constantly swapping between RAM and the hard disc drive
What are the three main types of storage device?
Magnetic discs, optical discs and solid-state (flash) memory
What are RAM and ROM?
Two types of computer memory
What does RAM stand for?
Random Access Memory
What does RAM do?
Stores data and instructions when an application is running
True/False: RAM can only be read from, not written to
False, RAM can be read from and written to
True/False: RAM is volatile
True
RAM is volatile… what does this mean?
If you turn off the power, data in RAM is lost
True/False: RAM is often removable
True
True/False: You can upgrade many computers by adding more RAM
True
What does ROM stand for?
Read Only Memory
What does ROM do?
Stores instructions that don’t need to be changed during normal use
True/False: Data can only be read from ROM
True
True/False: ROM is volatile
False, ROM is non-volatile
ROM is non-volatile… what does this mean?
It retains data even if the power is turned off
In a PC, the sets of instructions needed for the computer to start up are stored in ___
ROM
Why are the sets of instructions needed for the computer to start up stored in the ROM?
These instructions need to be stored and saved even after the power is turned off
True/False: Some applications (such as photo or video editing) require greater amounts of RAM
True
How much RAM does the typical smartphone have?
2GB
How much RAM does the typical games console have?
4GB
How much RAM does the typical laptop have?
8GB
How much RAM does the typical workstation have?
16GB
Where is virtual memory located?
In the hard disc drive or solid state drive
What is virtual memory used as?
Temporary RAM when the actual RAM is full
True/False: Program instructions and data are constantly moving between the CPU and the RAM
True
RAM may become ____ if many programs are running
full
What happens to data if there is no free RAM?
The operating system will swap out some of the data to the virtual memory
If the RAM is full, where is data swapped to?
Virtual memory
When data is swapped to virtual memory, where is the requested data swapped to?
The free area of the RAM
Usually the most/least recently used stored data is swapped out into virtual memory
least
What happens if data is swapped out to virtual memory and is needed again?
It is swapped back in at the expense of other data
The more RAM a computer has, the ____ virtual memory will be needed
less
What effect does adding more RAM have to the performance of a computer?
It will significantly improve it
The read/write speed of virtual emmory is much slower/faster than RAM
slower
Why will there be a significant performance drop if the system has to rely too heavily on virtual memory?
It is much slower than RAM
If the OS is constantly swapping between RAM and the hard disc drive, what happens to the speed of programs?
Disc thrashing - they will run more slowly
What is disc thrashing?
When the OS is constantly swapping between RAM and the hard disc drive, making programs run more slowly