3.3 CRM (Doshi) Flashcards
What is a check digit?
A mathematically calculated value that is added to data to ensure that the original data haS not been altered
Why check digit?
This helps in avoiding transposition and transcription errors.
Parity Bit
A method of error detection, it requires adding an extra bit (called parity bit) on the data.
Why would a parity bit be used?
It’s received by computer to ensure data completeness and data integrity during transmission.
Parity check
Is a hardware control that detects data errors when data is read from:
(1) one computer to another,
(2) from memory
(3) or during transmission.
Checksums
- 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
Cyclic Redundancy Checksums (CRC)/Redundancy Checksums
A more advanced version of checksums by increasing the complexity of the arithmetic
Forward Error Control
Works on same principle as CRC. However FEC also corrects the error. FEC provides the receiver with the ability to correct errors.
Atomicity:
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.)
When should a check digit be performed?
(1) When the objective is to identify transcription and transposition error.
(2) When the objective is to ensure accuracy,
What relevant controls MUST be performed when the objective is to identify transmission error?
(1) First preference is CRC
(2) If no CRC, them checksum,
(3) If no CRC and no checksum,
(4) Then, parity bit
What relevant controls are required to perform when objective is to ensure completeness?
First preference is CRC
If no CRC, them checksum,
If no CRC and no checksum,
Then, parity bit
What relevant control should be performed when the objective is to ensure integrity?
First preference is CRC
If no CRC, them checksum,
If no CRC and no checksum,
Then, parity bit
What relevant control should be performed when the objective is to correct (detect &correct) a transmission error?
Forward Error Control (FEC)
When should atomicity be performed?
To ensure that a transaction must either fully happen, or not happens at all.