Memory and Storage Flashcards
What is primary storage?
Primary storage refers to fast memory areas
that the CPU can access directly
CPU registers, cache, ROM and RAM
What is RAM (Random Access Memory) used for?
RAM is much faster than ROM and is used as temporary memory in which programs, applications and data are stored whilst they are being used.
If a computer loses power, all data stored in its RAM is lost.
This is known as “Volatile” data.
‘Random’ just refers to the fact that you can read or write anywhere in that memory space (you don’t have to put everything in order)/
What are the typical storage sizes for RAM in modern computers?
The more RAM you have, the more programs you can run at the same time which will generally make the computer run faster. RAM is relatively cheap and easy to upgrade and modern computers will typically have 8-32 GB of
RAM in 2-4 slots. For more demanding tasks like gaming, video editing, or graphic design, 32GB or even 64GB of RAM may be recommended.
What is Virtual Memory?
The RAM allows the computer to deal with the running programs but it is fixed size – 4GB, 8GB etc. When the computer is running a more complex application or when the user is trying to run several programs at the same time, the RAM can become full. When this is the case, part of the secondary storage can be allocated to become a temporary storage area to help the computer keep running. This area is known as “virtual memory” and is transferred back to the RAM when there is space.
What is ROM (Read Only Memory)?
Memory that cannot be changed by a program or user. It is used to store the instructions for the computer to start up when it is turned on – the BIOS (Basic Input/Output System). The data in the ROM is saved even if the computer is switched off and this is known as “non-volatile” data. As it doesn’t need to hold much data, ROM is usually only 4-8MB in size.
What is BIOS (Basic Input Output System)?
A low-level machine code program which forms the lowest layer of the operating system. It provides enough instructions for the computer to start before the main operating system loads. Although it is in ROM, it is possible to update some parts of it and most will provide a basic user interface.
What is Flash Memory?
Flash memory was developed from a type of ROM called ‘electrically erasable programmable read only memory’ (EEPROM). This is a form of memory that is re-writable but is non-volatile. Flash memory is relatively low cost, portable and robust.
What is Flash Memory used for?
memory cards in digital cameras.
Mini and micro SD cards in smartphones.
Memory cards in MP3 music players and video game
consoles.
USB memory sticks.
Solid state drives.
BIOS.
Flash memory is not as fast as RAM but is much faster
than accessing the magnetic hard disk and is often
used as a backup system.
State 4 differences between RAM and ROM.
RAM is volatile, ROM is non-volatile.
RAM can store more data than ROM.
RAM can be read and written, whereas ROM is only read.
RAM is a lot faster to access than ROM.
What is Secondary Storage?
Long term storage of programs and data, often an integral part of the computer, not directly accessible by the CPU.
Secondary storage tends to be the largest capacity but slowest access for data transfer
What is magnetic storage?
Magnetic storage uses different patterns of magnetisation in a magnetisable material to store data. Magnetised points on a pattern represents ‘1’ and demagnetised points represent ‘0’. A HDD (hard disk drive) is a type of magnetic storage.
What is optical storage?
Optical storage uses the reflection of light from a surface to represent data. When writing to optical media, the laser burns ‘pits’ into the shiny surface (land). When reading optical media, a laser is shone on its surface. When it hits a land, the beam reflects, but when it hits a pit, it doesn’t, representing the 1 and 0. Examples of this are CDs, DVDs, and Blu-ray.
What is solid state (flash) storage?
This works by sending a large electric current to force electrons through a barrier and trap them in position. The flash of the electric current used to achieve this gives us the name for this type of memory: Flash memory.
The different arrangements of electrons give us data, as each unique configuration represents a specific bit or set of bits.
- Flash of Electric Current
- Electrons forced through the barrier
- Arrangement of electrons is read by the computer
