CIE AS Computer Science Hardware

memory cache

high speed memory external to processor which stores data which the processor will need again

primary memory

the part of computer memory which can be accessed directly from the CPU

what does primary memory contain?

the RAM and ROM memory chips

what does RAM stand for?

random access memory

what does ROM stand for?

read-only memory

is access time to locate data faster in RAM or in secondary devices?

RAM

is the yellow part a track or sector?

sector

is the blue part a track or sector?

track

what is a removeable hard disk drive?

portable hard disk drive that is external to the computer, it can be connected via a USB port when required, often used as a device to back up files and data or as a way of transferring files between computers

what does SSD stand for?

solid state drive

what is an SSD?

storage media with no moving parts that relies on movement of electrons

is latency an issue in SSDs?

SSDs reduce the issue of latency considerably

is the data retrieved at the same or different rate in SSDs?

all data is retrieved at the same rate

do SSDs rely on magnetic properties?

no

how do the most common type of solid state drives storage devices store data?

by controlling the movement of electrons within NAND chips

how and where is data stored in SSDs?

the data is stored as 0s and 1s in millions of tiny transistors within the chip

are SSDs volatile or non-volatile?

non-volatile

are SSDs rewritable?

yes

what technology do a number of SSDs use?

EEPROM technology

what is the main difference between the most common types of SSDs compared to ones using EEPROM technology?

the use of NOR chips in ones using EEPROM rather than NAND chips

what effect does using EEPROM technology in SSDs have compared to the most common type of SSDs?

it makes them faster in operation but considerbaly more expensive

what difference does EEPROM technology in SSDs have in reading and erasing data?

EEPROM allows data to be read or erased in single bytes at a time, NAND usage only allows data blocks of data to be read or erased, this makes EEPROM more useful in certain applications where data needs to be accessed or erased in byte-size chunks

why do the majority of SSDs use NAND technology?

because of the cost of EEPROM

what kind of chips does flash memory use?

NAND

what are the advantages of SSD over HDD? (7)

more reliable - no moving parts to go wrong;
considerably lighter which makes them suitable for laptops;
do not have to get up to speed before they work properly;
have a lower power consumption;
run much cooler than HDDs;
are very thin because they have no moving parts;
access data considerably faster

what are the disadvantages of SSD over HDD? (1)

unknown longevity of the technology

what technology do memory sticks/flash memories/pen drives use?

solid state technology

how do memory sticks/flash memories/pen drives usually connect to the computer?

via the USB port

what is the main advantage of memory sticks/flash memories/pen drives?

they are small, lightweight devices which make them suitable for transferring files between computers and as small back-up devices

what is a dongle?

a small device that plugs into a computer and serves as an adapter or as a security measure to enable the use of the certain software

how do complex or expensive software (e.g. an expert system) often prevent illegal or unauthorised use of the software and prevent copying of the software?

using a memory stick as a dongle which contains additional files which are needed to run the software

what is optical storage?

CDs, DVDs and Blue-ray discs that use laser light to read and write data

how do CDs and DVDs store data?

using a thin layer of metal alloy or light-sensitive organic dye

what do CDs and DVDs contain?

a single, spiral track which runs from the centre of the disk to the edge

what happens when a CD or DVD disk spins?

the optical head moves to the point where the laser beam contacts the disk surface and follows the spiral track from the centre outwards

what is CD/DVD divided into? what does this allow for?

sectors, allowing direct access of data

which part of a CD disks /DVD disks/HDDs run faster?

the outer part

how is the data stored on the spiral track in CDs and DVDs?

in pits and bumps

how is data read and written in CDs and DVDs?

using a red laser