NALSD - Non-Abstract Large Sytem Design

Question 1

Power of two, 1KB?

Answer 1

1KB = 2^10 Bytes

Question 2

Power of two, 64KB?

Answer 2

64KB = 2^16 Bytes

Question 3

Power of two, 1MB?

Answer 3

1MB = 2^20 Bytes

Question 4

Power of two, 1GB?

Answer 4

1GB = 2^30 Bytes

Question 5

Power of two, 1TB?

Answer 5

1TB = 2^40 Bytes

Question 6

Power of two, 4GB?

Answer 6

4GB = 2^32 Bytes

Question 7

Time L1 cache reference?

Answer 7

0’5ns

Question 8

Time Branch mispredict?

Answer 8

5ns

Question 9

Time L2 cache reference?

Answer 9

7ns (14x L1)

Question 10

Time Mutex lock/unlock?

Answer 10

100ns (20x L2, 200x L1)

Question 11

Time compress 1KB with Zippy?

Answer 11

10.000ns = 10us

Question 12

Time send 1KB over a Gbit network?

Answer 12

10.000ns = 10us

Question 13

Time read 4KB randomly from SSD?

Answer 13

150.000ns = 150us

Question 14

Speed Round trips within same data center?

Answer 14

500.000ns = 500us

Question 15

Time to read 1MB sequentially, from memory?

Answer 15

250.000ns = 250us

Question 16

Time to read 1MB sequentially, from SSD?

Answer 16

1ms (4x Memory)

Question 17

Time Disk seek?

Answer 17

10ms (20x Data center round trip, 40x Memory)

Question 18

Time Read 1MB sequentially from Gbit network?

Answer 18

10ms (40x memory, 10x SSD)

Question 19

Time Read 1MB sequentially from disk?

Answer 19

30ms (120x memory, 30x SSD)

Question 20

Time of a Round-trip send between neighbor continents?

Answer 20

150ms

Question 21

Power of ten? (ns / us / ms)

Answer 21

ns = 10^-9 s
us = 10^-6 s
ms = 10^-3 s

Question 22

Speed Read sequentially from disk?

Answer 22

30MB/s

Question 23

Speed Read sequentially from Gbit network?

Answer 23

100MB/s

Question 24

Speed Read sequentially from SSD?

Answer 24

1GB/s

Question 25

Speed Read sequentially from memory?

Answer 25

4GB/s

Question 26

Number of world-wide Round-trips per second?

Answer 26

6-7 world-wide trips per second

Question 27

Size TCP header?

Answer 27

20B (TCPv4)

40B (TCPv6)

Question 28

Size UUID?

Answer 28

16B

Question 29

Size IP address?

Answer 29

32b (TCPv4)

128b (TCPv6)