1.2 – Memory and storage Flashcards
what is RAM
directly access any memory location in random order.
Stores the data which is currently being used. Stores the parts of the program that are running to be used by the CPU.
What is ROM
provides the necessary instructions for communication between various hardware components. Stores the BIOS.
What is primary storage
refers to the memory areas that the CPU can access very quickly. Primary storage is mostly volatile
what is secondary storage
is non-volatile, it’s where all data is stored when not in use. Secondary storage is much slower than primary.
what is volitile
looses data when the computer is switched off
Primary storage examples
Registers
Cache
RAM
ROM
Secondary storage examples:
Hard disks
USB
SD cards
what is virtual memory
enables data that is in RAM and not currently being used to be transferred to the hard disk. This frees up room in RAM for other programs and data.
what are the advantages of virtual memory
allows more programs to be opened even when there’s no space left in RAM
Disadvantages of virtual memory:
Takes time to write the code to the virtual memory
Cause disk thrashing
VM is slower to access than RAM direct (because it has to go back to RAM first)
why is secondary storage needed
To access it again later
To use software
To interact with the computer
what is optical storage
uses a laser to read and write data from a disc. Such as CDs
what is magnetic storage
uses magnetic metal platters. A read/write head reads the disk much like a record. Such as a hard disk.
what is solid state storage
offers fast access as there are no moving parts. Such as a memory stick.
advantages and disadvantages of SSD
they are fast and extremely durable due to no moving parts
advantages and disadvantages of magnetic
slower than SSD but are cheaper and offer more storage
may be prone to disk thrashing
advantages and disadvantages of optical
cheap
what is cloud storage
storage via the internet
advantages of cloud storage
may be accessed anywhere anytime
makes it easier to share files
can buy more storage
no need to back up data
no need for external hard drives
disadvantages of cloud storage
internet connection
hacked
only a certain amount of free storage
what is amplitude
This is the height (volume) of the sound
what is bit depth
Number of bits available to store each value.
what is sample frequency
This is the number of samples taken per second, measured in Hz.
what is bit rate
number of bits used per second of audio, measured in kilo bits per second.
how are sound waves understood by a computer
The amplitude (height) of the wave needs to be measured at regular intervals and converted into binary, this is called sampling.
what is compression
a reduction in the number of bits needed to represent data
advantages of compression
save storage capacity,
speed up file transfer,
decrease costs for storage hardware
network bandwidth.
what is lossy compression
Removes data from a file which cannot be restored. This lowers the quality.
what is lossless compression
It reduces the file size by not storing repeated detail
advantages of lossy
lowers the file size a lot
disadvantages of lossy
cant be used on text files
looses data which cant be turned back
quality is worse
advantages of lossless
same as the original
no reduction in quality
