2 input, output and storage devices

Question 1

what is a magnetic storage device?

Answer 1

magnetic storage devices are storage devices that uses magnets to read and write data. A hard drive is a type of magnetic storage, hard drives are used to store the operating system, software and user data. Another type of magnetic storage is a floppy disk.

Question 2

how does a hard drive store data?

Answer 2

hard drive are a magnetic medium and store data on a hard drive platter. data is read and written with the magnetic arm on an actuator with a special read head at the end.

Question 3

how does the hard drive read data?

Answer 3

the hard drive reads a change in polarity as a 1 or 0.

Question 4

what are the limitations of a hard drive?

Answer 4

limiting factors are the moving parts, the disk spins and the arm has to move to receive data.

Question 5

what is the main speed that a hard drive spins at?

Answer 5

most common speed for hard drives is 7200 RPM but it can vary as a hard drive running a server can run a 15000 RPM

Question 6

what is flash memory?

Answer 6

flash memory is a type of solid state storage, and is becoming more popular in modern computer systems as they are faster than magnetic disks.

Question 7

how to flash dives work?

Answer 7

flash drives use a special type of RAM called EEROM (electronically erasable programmable read-only memory).

Question 8

what are the disadvantages of flash storage?

Answer 8

flash storage is more expensive and have a lower capacity.

Question 9

what is the advantage of flash memory?

Answer 9

there are no moving parts so it makes it faster.

Question 10

how do optical drives work?

Answer 10

optical drives work by using lasers to store data by burning microscopic indentations into a disk such as a CD

Question 11

how is optical memory read?

Answer 11

optical memory is read by a laser and it reads the pits and lands burned into the disk. each pit and land is used to represent binary data.

Question 12

how are Blu-rays different to CDs and DVDs?

Answer 12

Blu-rays are made with a blue laser allowing the pit sand lands to be made closer together and therefore allowing more data to be stored on the disk.

Question 13

what is RAID?

Answer 13

RAID (redundant array of independent discs) a data storage virtualization technology that combines multiple physical disk drive components into a single logical unit for the purposes of data redundancy, performance improvement, or both.

Question 14

what is RAID level 0?

Answer 14

RAID 0 striped: this provides improved performance and additional storage. however it does not provide any fault tolerance, so errors on the discs could destroy the RAID.

Question 15

what is RAID level 1?

Answer 15

RAID 1 mirrored: each disc provides the same information, which provides some fault tolerance. as data is repeated, read time is increased, but write time is decreased.

Question 16

what is RAID level 3-4?

Answer 16

RAID 3-4 striped parity: this requires three discs in the array, as well as fault tolerance it provides parity checks and error correction. the parity information is stored on a single drive, so the other drives can continue working when one of the drives fails. the loss of data can be calculated using the parity data stored on the parity drive.

Question 17

what is SAN?

Answer 17

A SAN (storage area network) provides a greater degree of scalability than RAIDs. A SAN will act as a gate way to a series of block devices such as RAIDs. A SAN could be seen as a subnet of a network that is solely responsible for serving files. this allows us to see it as one logical drive.

Question 18

what is virtual storage?

Answer 18

the cloud is an example of virtual storage. Virtual storage allows us to simulate many drives on the computer. Virtual storage hides the complexities of the physical storage and makes it easier to manage.

Question 19

what are the benefits of virtual storage?

Answer 19

because virtual storage allows us to hide the complexity it is easier to access, it also allows us to offer key services such as backup and archiving.

Question 20

what is RAM?

Answer 20

RAM is used as main memory. It acts as a temporary store for program instructions and data that are important at that time.

Question 21

what are the features of RAM?

Answer 21

It is volatile this mans without a power source it can not retain information. It is fast as RAM can be accessed in any order this is why it’s called random access memory and it is because of this that the CPU can access any memory location . RAM holds billions of storage locations, each with its own memory address. The number of blocks will be dependent on the size of the RAM.

Question 22

what is ROM?

Answer 22

ROM is a special kind of memory which stores the instructions which the computer uses when it “boots up”. The BIOS (basic input output system), allows it to check the type of hard disk installed, the amount of RAM installed, the type of CPU, etc…

Question 23

what are the features of ROM?

Answer 23

ROM is non-volatile an read only so it cant be over written, this kind of memory is needed because the computer must be able to obtain instructions from the moment it is switched on and must know some basic things about the hardware. The ROM chip is attached to the motherboard.