What term describes a bit-for-bit copy of a data file, disk partition, or entire drive?

A bit-for-bit copy of a data file, disk partition, or entire drive is referred to as a raw image. This term represents an exact digital representation of the original data which preserves every single bit, including both the used and unused space on the drive or partition. The creation of a raw image is essential in digital forensics as it allows investigators to analyze the data without altering the original evidence. This integrity is crucial as any modification to the source data could compromise the investigation.

In contrast, a complete backup typically involves copying only the data that is currently used or specified for backup, which may not include the entirety of the drive or partitions in their original form. A system snapshot usually captures the state of a system at a particular moment, which may not provide a comprehensive bit-for-bit representation. A compressed file refers to a file that has been reduced in size for storage efficiency, which also does not maintain a bit-for-bit exactness of the original data.