SLR 1.2 part 1 Flashcards
what does primary storage consist of
RAM, ROM, registers and cache
the 3 types of storage
primary storage, secondary storage, tertiary storage
secondary storage consists of…
the operating system, programs and data that is held while the computer is off
tertiary storage
used for backing up and archiving lots of data
volatile storage
data held in the storage that can be lost when the computer is off
differences between volatile and non volatile storage
primary storage is measured in giggabytes, secondary storage is measured in terrabytes
secondary storage is non volatile, secondary storage has slower access times
access times
how quickly you can read from or write to a device
RAM
random access memory, holds the operating system, programs and data in use by the CPU when the computer is running
temporary storage
ROM
read only memory, holds the first instrutctions for when the computer is turned on
also known as the bootstrap
difference between RAM and ROM
RAM is volatile whereas ROM is non-volatile
ROM is smaller in size whereas RAM has a larger size
ROM is read only memory whereas RAM Is read and write
virtual memory
held in hard disk
used if there is not enough RAM to store open programs
how virtual memory is used
if a program is not being used, it can be transferred from the RAM to the virtual memory. when a program is needed, it is transferred back from the virtual memory to the RAM
enables more programs to run and is ideal for multitasking
why cant ROM hold storage
doe not have the physical
it is read only
why is secondary storage needed
when computer is off so data is not lost
semi-permanent storage
back up data and files
archive data files
drive
reads and writes data from secondary storage
media
what data is actually stored on
types of secondary storage
optical, magnetic, SSD
types of optical storage
CDR - compact disk read-only
CDWR - compact disk read write
DVDR - digital versatile disc read only
DVDWR - digital versatile disc read write
blu ray - designed to super code DVD - has greatest storage
how optical storage work
laser physically burns disk, making pits and lands which represents 1 and 0s.
are optical drives good?
they are cheap, light and portable but have slow access times and prone to scratches
how does magnetic hard discs work
uses magnetised compounds as format for 1 and 0s. have a drive that physically moves over the surface of the disc
are magnetic hard discs good?
they are cheap and have a large capacity, but they are slow and fragile
how does SSD work?
using a flow of electricity forcing electrons into floating gates between two oxide layers.
is SSD good?
they are durable and have fast access times, but they are expensive and have limited read and write cycles, so they have short lifespan.
they make no noise require low power and have medium storage
