Reliability and Backing-up Flashcards
What kind of testing is done in-house by the software developers?
Alpha testing is done before trialling the software with trusted beta users or releasing it to end users.
Which measure of reliability would you use to estimate how long a new server is going to last before it fails?
Mean time to failure (MTTF) measure how long it might be until the new server will fail after it is first installed.
What is validation testing?
Validation testing checks the type of data that the system can use, ensuring that the dat input is sensible.
What does failing gracefully mean?
Failing gracefully is where the system tries to avoid the loss of data when problems occur, usually by writing an emergency copy of the data before shutting down - this is known as a dump file, a recoverable version of a document.
What happens when an incremental backup is made?
An incremental backup will only backup files that are new or that have changed since the last backup was taken.
What is disaster recovery?
Disaster recovery is the policy for getting an IT system up and running again after a failure, whether caused naturally or by human error.
How would a system use redundant array of in depend disks (RAID) in case of failure?
A server can use RAID storage to make not just one copy, but many copies of the same files in case a disk fails. If one (or more) of the disks fails, the data should still safely exist on at least on elf the other disks.
What does defensive programming mean?
Defensive programming means that the program contains special checks to detect a possible failure or crash.
What are the consequences of not testing new software thoroughly?
New software that has not been tested thoroughly may contain bugs that has not yet been discovered.
