Memory and storage

Why is primary storage not completely volatile

- Because it contains RAM and ROM and RAM and Cache. - RAM is volatile but ROM is non-volatile (boot info is permanent)

How does blue ray work

- Blue laser rather than red - read and write operations - pits and pumps smaller - five times more data storage - secure encryption system built-in

How does solid state work

- Chips store the data - High speed flash memory used to store data - Uses NAND chips for flash memory stored as 1's and 0's in millions of transistors

How does magnetic storage work

- Data stored magnetically. - HDD, magnetic tape and floppy disks are examples of this. - Magnetic coated discs spin around. - A read write head moves to read or write the data. - The bits are coded, read and erased using magnetic fields created by tiny electromagnets -The information is accessed using one or more read-write heads.

Describe HDD

- HDD has multiple discs and read-write heads. - Read-write heads move quickly 50 times a second and data is stored in sectors and tracks - A sector on a track will have a set number of bytes worth of storage

Advantages of magnetic storage

- Large capacity -reliable - long life span -cheap - easily available

What is the difference between memory and storage

- Memory refers to RAM. Memory is volatile. - Storage refers to hard drive/solid state drive. Storage is non-volatile

How does removable HDD work

- Plugged into a computer with a USB - same as internal HDD - digital data is stored on the magnetic surfaces

What does volatile mean

- Requires constant power to maintain the stored information - Needs to be fast - if there is a power cut data in volatile storage is lost

Disadvantages of magnetic storage

- Slow compared to solid state - prone to damage due to moving parts

How does optical storage work

- Stored with indentations on the medium - Uses light reflections from the surface of a data area - The surface has a dye layer on it which is changed by shining a laser on it - It is the colour difference that is detected when it is read

How does a CD work?

- Thin layer of light sensitive organic dye to store data - laser light is used to read and write data in the surface of the disk - single spiral track - read using a laser - data stored in pits and bumps

Describe SRAM

- Used in cache - does not need to be constantly refreshed - More expensive to make - higher power consumption, higher storage capacity compared to DRAM but faster to access data

How does USB flash memory work

- data is flashed onto silicon chips - uses NAND/NOR tech - uses transistors to control the flow of electrons - type of EEPROM tech - when data is stored the transistor is converted from 1-0 or 0-1 Writes and reads sequentially

How does DVD-RAM work

- there are many concentric tracks that allow simultaneous read and write comfretation - there are 100,000 large write cycles

Description of RAM

-Stores data, files, part of OS being used - does not run out of memory, it just gets slower. - It's volatile and communicates with the CPU. - When RAM becomes full, the process has to access the hard disk to overwrite old data with new data

What type of storage would b most suitable for use in a web server and why

1) - Magnetic // HDD − (Web server) is likely to receive many requests a day − (Web server) will likely need to store a lot of data and magnetic is high capacity − Magnetic is cheaper to buy for storage per unit than solid state − Magnetic is capable of more of read/write requests over time // has more longevity // SSD has more limited number of read/write requests (before it is no longer usable) − No requirement for it to be portable, so moving parts does not matter OR 2) Solid-state // SSD − (Web server) is likely to receive many requests a day − (Web server) will likely need to store a lot of data and solid-state is high capacity − Solid-state is more energy efficient − Solid-state runs cooler so will not overheat − Solid state has faster read/write speeds to handle volume of traffic

How many kB in 3GB

3 x 1024 = 3072 3072 x 1024 = 3145728 Answer = 3145728

The school tracks students progress on tests. An entire student record takes 3 kB to store. The back up system stores data at 3MB per minute. How many records can be transferred in a minute?

3MB x 1024 = 3072kB 3072/3= 1024 files Answer = 1024

How many bytes in 48 kB

48 x 1024 = 49152 Answer = 49152

How many kb in a kB

8

Pete wants to store his DVD collection on a 500 GB external HDD. How many of his DVDs (6.2 GB's) will he be able to store

80

What's the use for DVD-RAM

Archive or backup

What unit of storage would a single 1 or 0 be

Bit

What unit of storage would a single keyboard character (A) be

Byte

Advantages of optical storage

Cheap for small amounts Portable

Cost of magnetic storage

Cheapest

Benefit of increasing RAM capacity?

Computer runs faster

What is off-line storage

Example- CD, DVD, USB flash, external HDD Definition: - huge storage space but slow to access -portable - Stores data but unlike second dairy can be removed - Only accessed when connected to the computer - Often used for backups for portability reasons

What is secondary storage

Example- HDD, SSD Definition: - medium storage space and medium access speed - Cannot be processed directly by the CPU and stores user files - OS and software applications permanently

What is primary storage

Example- RAM, ROM Definition: - small space but very fast access - Computer memory that is accessed directly by the CPU

Disadvantages of solid state

Expensive and smaller capacity

Speed of cache

Fastest memory in computer

What are the different types of solid state drive?

Flash memory systems and RAM systems

What is stored in cache

Frequently accessed in main memory

What unit of storage would a Hollywood blockbuster movie be

Gigabyte

Life span of optical storage

Good/medium

Use of blue ray

HD movies

What does HDD stand for

Hard Disk Drive

Describe DRAM

Has a capacity- holds bits and transfer like a switch and needs to be constantly refreshed

Durability of solid state

High-no moving parts

Cost of solid state

High/most

What is durability (in relation to storage devices)

How long the storage media can reasonably be expected to last

What is speed (in relation to storage devices)

How quickly the user needs to be able to access the data from storage device

What is reliability (in relation to storage devices)

If the data can always be accessed with accuracy

What unit of storage would a simple piece of clipart be

Kilobyte

Durability of magnetic storage

Least

Life span of magnetic storage

Longest

Life span of solid state

Lowest

What type of storage is removable HDD

Magnetic

Put these in the right format Optical Floppy disks Data stored as a series of charged areas Magnetic CD Data is written to chips. It can be erased using elec signals EEPROM Thumb drive Data is stored by tiny "pits" pressed into the medium

Magnetic Floppy disks Data stored as a series of charged areas Optical CD Data is stored by tiny "pits" pressed into the medium EEPROM Thumb drive Data is written to chips. It can be erased using elec signals

Cost of optical storage

Medium

Durability of optical storage

Medium

What unit of storage would an MP3 song be

Megabyte

Use of DVD

Movies

Disadvantages of optical storage

Must have optical drive Available in small capacity

Where is cache loated

On/near CPU

What type of storage is CD

Optical

What type of storage is DVD-RAM

Optical

What type of storage is a DVD

Optical

What type of storage is blue-ray

Optical

Advantages of solid state

Quieter Cooler Lighter

Example of where solid state is used

RAM

What does RAM stand for

Random Access Memory

Fill in the gaps: RAM stands for _______ ________ memory. It is where the ________ instructions are stored after they have been loaded from disk so that they can be accessed more _________ by the CPU. Instructions and data are stored in ________ format at specific locations called memory ________ which can be accessed in any _________.the main memory is made of _________ RAM which is slower than _________ RAM as it needs to be constantly _________ or refreshed.

Random, access, program, quickly, binary, addresses, order, dynamic, static, recharged

What does ROM stand for?

Read Only Memory

What is the difference between read-write and read-only memory

Read write- can read, update, and erase data Read only-cannot be updated or erased, only read

How does a DVD work

Same as CD except uses dual layering to increase capacity - Thin layer of light sensitive organic dye to store data - laser light is used to read and write data in the surface of the disk - single spiral track - read using a laser - data stored in pits and bumps)

What is the difference between sequential and random access

Sequential- accessed one after another Random- any location in storage can be accessed at any moment in approximately the same time

Uses of USB flash memory

Storage and data nackup

What are the uses of secondary storage

Storing user files Storing the operating system Storing software

What unit of storage would 300 hours of high quality video be

Terabyte

What is capacity (in relation to storage devices)

The amount of data that can be stored

What is latency (in relation to HDD)

The time it takes for the specific block of data on a track to spin around to the read-write head

Uses of removable HDD

Transporting user files

Definition of cache

Volatile memory that is located on the CPU which is fast to access Usually stores frequently access to data

What is portability (in relation to storage devices)

Whether the data needs to be moved from one place to another

What does DRAM stand for?

dynamic random access memory

What type of storage is USB flash memory

solid-state

What does SRAM stand for

static random access memory