Chapter 6 - Memory and Data Storage

Question 1

What is a Musical Instrument digital interface?

Answer 1

MIDI for short
the storage of music files - consists of lists of commands which instruct a device on how to produce a musical note/sound

Question 2

What is MPEG-3 (MP3)?

Answer 2

uses audio compression to store music in MP3 file format

Question 3

What is MPEG-4 (MP4)?

Answer 3

can store multimedia rather than just music

Question 4

What is Joint Photographic Experts Group (JPEG)?

Answer 4

JPEG uses a lossy format file compression method to store photographs at a reduced file size

Question 5

What is lossless file compression?

Answer 5

all the data from the original files are reconstructed when the file is uncompressed

Question 6

What is lossy file compression?

Answer 6

unnecessary data is removed forming a file that cannot be reconstructed to its original file

Question 7

What are examples of primary memory?

Answer 7

RAM, SRAM, DRAM, ROM

Question 8

What are examples of secondary storage?

Answer 8

hard disk drives
solid-state drives
offline storage (CDs, DVDs, DVD-RAM, DVD-ROM and blu-ray disks)

Question 9

Why are MIDI files so small?

Answer 9

don’t contain actual audio tracks

suitable for storing sounds/music on devices with limited memory

Question 10

What is perceptual music shaping?

Answer 10

removing sounds that the human ear can not clearly distinguish

Question 11

How is text usually stored?

Answer 11

ASCII file format

lossless: accuracy of data is important

Question 12

Which primary memory is volatile?

Answer 12

RAM

Question 13

Can RAM be written to and read from?

Answer 13

yes

Question 14

How does DRAM work?

Answer 14

needs to be constantly refreshed to retain the data

uses millions of transistors and capacitators

Question 15

How does SRAM work?

Answer 15

does not need to be constantly refreshed to retain its data

uses flip-flops

Question 16

Which primary memory is non-volatile?

Answer 16

ROM

Question 17

What does ROM store?

Answer 17

used to store start-up procedures or BIOS

Question 18

What do hard disk drives use?

Answer 18

circular platters coated in magnetic material

Question 19

What is used so that all surfaces can be accessed?

Answer 19

read-write heads

Question 20

How is data stored in hard disk drives?

Answer 20

sectors and tracks in block

Question 21

What is latency?

Answer 21

the time taken for a specific block of data on a track to rotate around to the read-write head

Question 22

Why is latency not an issue in SSD?

Answer 22

they have no moving parts
all data retrieved at the same rate
therefore no latency

Question 23

What do the most common types of SSD use to control the movement of electrons (and therefore data)?

Answer 23

NAND chips

Question 24

What do EEPROMS (electronically erasable programable read-only memory) use?

Answer 24

NOR chips

Question 25

What are the advantages of SSDs over HDD?

Answer 25

more reliable and robust (no moving parts)
much lighter and thinner
consumer less power and run cooler
does not need to get up to speed
faster data access rate

Question 26

What do CDs and DVDs use to write and read data?

Answer 26

red laser light

Question 27

What does the suffix -R on CDs/DVDs mean?

Answer 27

write once and then only be read

Question 28

What does the suffix -RW on CDs/DVDs mean?

Answer 28

can be written to and read from several times

Question 29

Why do DVDs hold more data than CDs?

Answer 29

dual layering technology (they have two individual recording layers)

Question 30

What type of technology is nearly obsolescent?

Answer 30

DVD-RAM

Question 31

How does DVD-RAM work?

Answer 31

uses a number of concentric tracks enabling simultaneous read-write operations to take place

Question 32

Why are DVD-RAM ideal for archiving data?

Answer 32

they have great longevity

Question 33

What do blu-ray disks use to read and write data?

Answer 33

blue laser light

Question 34

Why can blu-ray disks hold more data than CDs and DVDs?

Answer 34

wavelength of blue light is 405nm
wavelength of red light is 650nm
can store more data

Question 35

Why do blu-rays not suffer from birefringence (light reflection into two separate beams causing reading errors)?

Answer 35

they use single polycarbonate disks rather than DVDs which use a sandwich of two polycarbonate disks

Question 36

What technology do flash memory/memory sticks use?

Answer 36

solid-state technology

Question 37

How do flash memory/memory sticks usually connect to the computer?

Answer 37

USB port

Question 38

Why are flash memory/memory sticks ideal for transferring files and photos between different computers?

Answer 38

small and lightweight

Question 39

What needs to happen for flash memory/memory sticks to retain their data integrity?

Answer 39

read every now and again