Data Recovery Glossary

OpenZFS

OpenZFS is an open-source project developing a storage platfrom based on the ZFS filesystem.

Operator error

Operator error - class of errors caused by incorrect actions on behalf of user, as opposed to a system malfunction. Formatting of a wrong partition resulting in data loss is a typical example of an operator error.

OS

OS (Operating System) - a set of programs allowing user to interact with a computer. OS provides user with a convenient interface hiding details of different organization levels of computer components (hard drives, CPU commands and so on). Most widely known operating systems are:

• Windows,
• Mac OS,
• Linux

Overclocking

Overclocking - the increase of a computer speed above a vendor-certified standard by changing the system settings. The typical side effect of the overclocking is the system instability.

Overhead

Overhead (in disk space) - disk space which is not used to store user data, but either provides redundancy in a storage system (e.g. in RAID1 or RAID5), or is used for filesystem control structures.

Overheating

Overheating - a phenomenon when a system doesn't work properly because some components (e.g. CPU, GPU, or memory) got too hot. There are certain temperature limits after which the modern semiconductors cease to function. As a rule, for a chip anything below 60⁰C is fine, anything higher than 95⁰C is bad, and between there is a gray "mostly OK" area. For a hard drive, everything below 55⁰C is fine, above that you should think about improving ventilation.

Overwritten data

Overwritten data - data which has been deleted from a storage device and then new data was written onto the same storage space. It is impossible to recover overwritten data.