Many digital forensic tools used by investigators were not originally designed for forensic applications. Even in the case of tools created with the forensic process in mind, there is the issue of assuring their reliability and dependability. Given the nature of investigations and the fact that the data collected and analyzed by the tools must be presented as evidence, it is important that digital forensic tools be validated and verified before they are deployed. This paper engages a systematic description of the digital forensic discipline that is obtained by mapping its fundamental functions. The function mapping is used to construct a detailed function-oriented validation and verification framework for digital forensic tools. This paper focuses on the data recovery function. The data recovery requirements are specified and a reference set is presented to test forensic tools that implement the data recovery function.