It may be possible to retreive the data without openning a drive. I can think of two methods for achieving this objective. Firstly, I've seen reference to SCSI

It may be possible to retreive the data without openning a drive. I can think of two methods for achieving this objective. Firstly, I've seen reference to SCSI commands to retrieve "unbaked" sectors from CDROMs. Support for this functionality varies but it may be possible that some harddisks have undocumented functionality. You may wish to check the widespread implementation of DRM in harddisks for circumstantial evidence of such functionality. Alternatively, it may be possible to replace harddisk firmware which allows retrieval of magnetic traces. Again, I've seen reference to "low-level formatting" which wipes harddisk firmware. If the firmware is accessible in this manner then retreival is possible for almost all harddisks without openning them. It would also demonstrate that data recovery services are doing a shoddy job of imaging disks, running some standard recovery tools, and maybe performing some sector edits. This test raises the bar because you have three days and writing to the disk is not allowed. That would leave you with three days to reverse engineer the existing firmware.