1.2 memory and storage Flashcards
RAM
RAM stands for Random Access Memory. It is also referred to as the computers Main Memory. This is because it is the memory that the CPU has direct access to.
The job role of RAM is to store all the computers open programs and
files. When a program/file is loaded up, it is opened from Secondary Storage and stored in the RAM. This is so the CPU can access the program/file and its data quicker.
The process for loading up a program or file is:
- The user clicks on a program or file to open it up
- The program or file is loaded from the hard drive (Secondary Storage)
- It is stored in the RAM so the CPU can access it quickly
- The user uses the program or file
- Once finished, the user closes down the program or file. It is then removed from the
RAM, and stored back in the hard drive
ROM
Read only memory.It can only be read and is not rewritable(cannot be changed).
stores the program required for botting up the computer system-called BIOS(BASIC INPUT/OUTPUT SYSTEM)
What did BIOS store
all the instructions for the computer system to boot up and work.
Operating system
allows the user to interact and use the device.
Difference between ROM and RAM
RAM is volatile,ROM is not
RAM IS REWRITABLE,ROM IS READ ONLY.
RAM is GB-so the device has a large amount of storage in RAM,therefore more programs can be open at once without RAM being filled up quickly.
ROM IS ONLY MB OR KB AS IT ONLY CONTAINS THE BIOS AND THEREFORE DOES NOT NEED TO BE ANY BIGGER
Virtual memory
Sometimes, when a user has a large number of programs or files open at once, the RAM can
become full. Rather than the computer simply stopping anymore programs or files being
opened, the computer makes use of virtual memory.
Virtual memory is used when the RAM becomes full. When this happens, part of the internal
Hard Drive is partitioned (sectioned off) and acts as additional RAM. This allows further
programs and files to be opened and allows the computer to continue to function.
How does virtual memory affect performance
The CPU does not have direct
access to the virtual memory. Therefore, any programs or files that are stored in the virtual
memory must be swapped into RAM (and something else swapped out of RAM and into the
virtual memory) for them to be actively used. This process slows the performance of the
device down.
How to avoid using virtual memory because it affects peffomance of device
upgrade RAM-it would take longer for the RAM to become full
Secondary storage
A non volatile area where programs and files can be saved and will not be lost once computer is turned off.
Three main types of secondary storage
-opticcal
magnetic
solid state
Optical storage
-where a laser is shone at
the surface of the disc, and then processing the reflection from the disc.
Optical Storages are discs, and examples are CDs, DVDs, and Blu-Rays.
Magnetic storage
Data is stored on Magnetic Storage via magnetised dots. Magnetic
Storage often has moving parts. An example of Magnetic Storage is a
Hard Disc Drive (HDD). Another example is a Floppy Disk; however, these
are no longer used due to their poor durability and
reliability.
Solid state storage
Data is stored on Solid State Storage via electricity. It is becoming
increasingly popular as its capacity increases, and its cost decreases.
Examples of Solid-State Storages are Memory Sticks, SSDs, and SD
Cards.
Capacity speed portablilty and durability of Optical storage
Optical – Advantages: Cheap, portable, average durability and reliability
Disadvantages: Small capacity, slow data transfer speed
Capacity speed portablilty and durability of magnetic
Advantages: Large capacity, fast data transfer speed, relatively cheap per unit
of storage
Disadvantages: Not durable, not portable
Capacity speed portablilty and durability of solid state
Solid State – Advantages: Durable, reliable, easily portable, fast transfer speed
Disadvantages: Price can vary depending on the media you choose
the units
BLUE.NARWHALS.BE.KILLING.MY.GREEN.TOMATOES.PERIOD
bit.nibble.byte.kilobyte.megabyte.gigabyte.terabyte,petabyte
unit laws
There are 4 bits in a nibble, and 8 bits in a byte
* There are 2 nibbles in a byte
* There are 1024 bytes in a kilobyte
* There are 1024 kilobytes in a megabyte
* There are 1024 megabytes in a gigabyte
* There are 1024 gigabytes in a terabyte
* There are 1024 terabytes in a petabyte