3 CRM

Question 1

What is a check digit?

Answer 1

A mathematically calculated value that is added to data to ensure that the original data have not been altered

Question 2

Why check digit?

Answer 2

This helps in avoiding transposition and transcription errors.

Question 3

Parity Bit

Answer 3

A method of error detection, it requires adding an extra bit (called parity bit) on the data.

Question 4

Why parity bit

Answer 4

It’s received by computer to ensure data completeness and data integrity during transmission.

Question 5

Parity check

Answer 5

Is a hardware control that detects data errors when data are read from one computer to another, from memory or during transmission.

Question 6

Checksums

Answer 6

Programs that compute checksums can be run against old and new databases to ensure the accuracy of migrated data.
Checksum ensure is data copied is the same as original

Question 7

Cyclic Redundancy Checksums (CRC)/Redundancy Checksums

Answer 7

More advanced version of checksums by increasing the complexity of the arithmetic

Question 8

Forward Error Control

Answer 8

Works on same principle as CRC. However FEC also corrects the error. FEC provides the receiver with the ability to correct errors.

Question 9

Atomicity:

Answer 9

Atomicity is a feature of databases systems where a transaction must be all-or-nothing. That is, the
transaction must either fully happen, or not happens at all.

Question 10

When to perform a check digit?

Answer 10

1- When objective is to identify transcription and transposition error.

2- When objective is to ensure accuracy,

Question 11

What relevant control to perform when objective is to identify transmission error

Answer 11

First preference is CRC
If no CRC, them checksum,
If no CRC and no checksum,
Then, parity bit

Question 12

What relevant control to perform when objective is to ensure completeness

Answer 12

First preference is CRC
If no CRC, them checksum,
If no CRC and no checksum,
Then, parity bit

Question 13

What relevant control to perform when objective is to ensure integrity,

Answer 13

First preference is CRC
If no CRC, them checksum,
If no CRC and no checksum,
Then, parity bit

Question 14

What relevant control to perform when objective is to correct (detect & correct) transmission error

Answer 14

Forward Error Control (FEC)

Question 15

When to perform atomicity

Answer 15

To ensure that a transaction must either fully happen, or not happens at all.