Mass storage

Question 1

What is the name of the bit-sized needle on the end of an actuator? (HDD)

Answer 1

A transducer

Question 2

True or false: There are not just one, but two read/write heads. One on the top of the platter and one on the bottom?

Answer 2

True

Question 3

What is platter RPM and what is its alternate name?

Answer 3

Revolutions per minute, Spindle Speed

Question 4

What sizes do HDD come in? (Inches)

Answer 4

2.5, 3.5

Question 5

What are three cons of using a HDD?

Answer 5

Spin-up time at start, moving parts are a liability, generates heat quickly

Question 6

True or false: SSDs use flash memory chips

Answer 6

True

Question 7

M.2 uses keys to tell you what the port is capable of. What are the keys to indicate mass storage use?

Answer 7

B, M, B+M

Question 8

What is the more efficient alternative to Multi-level cell (MLC)

Answer 8

Single-level cell

Question 9

What is sequential read/write?

Answer 9

Reading/Writing to long files or things that are in order on the memory storage device.

Question 10

When do Sequential read/write speeds come into play in real life situations?

Answer 10

Video editing, large files.

Question 11

What unit of measurement is used when measuring Random read/write speeds?

Answer 11

Input Output per second. IOPS. “4k Read” also implies the data chunk used in the test is 4KB large. So the test consisted of the drive randomly finding and writing 4KB chunks as fast as it could.

Question 12

What is latency usually measured in?

Answer 12

Nanoseconds, microseconds

Question 13

What real life situation would benefit from high random read/write speeds?

Answer 13

A file server

Question 14

What are the speeds of Sata 1, 2 and 3?

Answer 14

1.5, 3 and 6 gbps. 20% overhead for the encoding scheme means the speeds drop to about 150, 300, 600 MBps.

Question 15

What is an external enclosure?

Answer 15

A casing of external HDDs or SSDs. Ex: A raid box.

Question 16

What is the maximum length of a sata cable (internal)?

Answer 16

1 meter

Question 17

What is AHCI?

Answer 17

Advanced Host Controller Interface - made to optimize spinning drives

Question 18

What does NVMe mean?

Answer 18

Non-volatile memory express

Question 19

What does SCSI stand for and what is it used in?

Answer 19

Small computers system interface. Used on servers.

Question 20

True or false: There is a an alternate SCSI called Serial attached SCSI that uses serial delivery instead of parallel?

Answer 20

True. It also supports sata drives.

Question 21

Explain Raid 0, 1 (and duplexing), 5, 6, 10 and 01

Answer 21

0 - Striped
1 - Mirrored
5 - Stripe w/ parity
6 - Stripe w/ parity with 2 parity blocks per HDD instead of one
10 - A1, A1 | A2, A2
01 - A1, A2 | A1, A2

Question 22

What is the min drive amount for raid 6?

Answer 22

4 - Each drive has two parity pieces instead of one (as is the case with Raid 5)

because of the additional parity space needed, and the fact that raid 6 allows for 2 disk failures, this means 4 drives are required.

Question 23

Min drive amount for raid 5?

Answer 23

3

Question 24

Raid software vs hardware - Which is more efficient?

Answer 24

Hardware. Software can strain your OS if too many disks are added. Hardware has its own chips and setup through flash rom.

Question 25

True or false: Some hardware raid controllers allow for you to hot-swap bad drives?

Answer 25

True