Topic 2 - Memory and Storage Flashcards
RAM
- volatile memory that can be read and written to
- it is used as the main memory and stores all the data, files and programs while they’re being used
- temporary storage for programs and data while the program is being executed`
ROM
- non-volatile memory that only be read to
- it contains all the instructions the computer needs to properly boot up, called the BIOS
- tells CPU to perform self checks, etc
Virtual memory
- a location on secondary storage that stores application data when the RAM is too full
- needed when too many applications open at once
Why does use of virtual memory slow down the computer?
if the CPU needs to read data stored in virtual memory it must move the data back to RAM
This is slow because data transfer rates are slower on seconder storage
Causes disk thrashing which decreases performance
How does RAM make the computer system faster?
- The more RAM, the more memory intensive applications it can smoothly run
When does increasing RAM have no effect?
If the computer already has enough RAM to run all the applications, then increasing RAM will make no differnce to performance
What does the GPU do?
They are specialised circuits used for handling graphics and image processing
They relieve the processing load on the CPU
What does the GPU improve performance of?
Graphic intensive applications like PC gaming and design software
Why is secondary storage needed?
- needed to store data and software in the long term, but not accessible by CPU
- it is non volatile so retains data when there is no power
- has a high capacity so it can store more data
What are the 3 types of secondary storage ( O, M, S)
- optical
- magnetic
- solid state
What are 5 characteristics to consider when choosing a secondary storage device ( C,C,D,P,S)
- capacity
- cost
- durability
- portability
- speed
how do magnetic devices work? examples?
- read with a moving head inside disk drive
- bits of the disk are magnetised or not ( represent 1s and 0s)
- Hard Disk Drives (HDDs), floppy disks
how do solid state drives work? examples?
- no moving parts and use type of flash memory to store data
- USB pen drives, SD cards
how do optical devices work?
examples?
- data is stored as pits and lands on the disk
- read by laser which interprets them as 0s or 1s
- CD , DVD , Blu-ray
advantages of solid state
- compact
- lightweight
- portable
disadvantages of solid state
- very expensive
- has a lower capacity than magnetic storage
advantages of Optical
portable
cheap
waterproof
disadvantages of Optical
low capacity
slow read/write speeds
poor reliabilty
advantages of Magnetic
- large capacity
- cheap
disadvantages of Magnetic
- can easily be damaged
- affected by magnetic fields
