Western Digital donor parts – DCM configuration
Matching the DCM configuration of a donor and patient hard disk drive is critical to the success of any replacement of the failed HDD’s head-assembly. The DCM code provides information about the internal configuration of the hard disk drive including the head-stack and pre-amplifier type.
The HDD had incorrect ROM content (or non-native PCB) and a failure of read-write head 0. The donor we had available had an exact match on the DCM configuration.
One of the most comprehensive articles on the DCM configuration can be found on HDD Oracle. Deepspar, the manufacturer of one of the lead hardware disk imaging equipment also provides a good article titled, “How to Find a Better Drive.”
These articles also provide an insight into the requirements for matching other engineering revisions. There are several vendor-specific parameters located in the ROM and RAM of the drive help in finding a donor with better compatibility, including:
- Head map
- Microjog adaptives
- Drive information table
- Firmware release
Unfortunately, none of the parameters associated with the four items listed above are located on the label of a hard disk drive. It is only possible to access this information with equipment used for data recovery (e.g. PC3000). This means that when ordering a donor HDD there is a chance that the HDD ordered will not be a good enough match for the purposes of data recovery donor drive.
Frequently we can find Western Digital HDD which have the same model number, manufacturer site code and date, and yet have the an incompatible DCM configuration or different head-map. This is why is it necessary for data recovery companies to hold stock of a library of donor parts. When customers have attempted to find a matching donor HDD they have quickly realised how difficult it can be to find a good match. CDR – Manchester Data Recovery Services – provides quotations which include the cost of any donor parts required. There are never any upfront or non-refundable fees for the donor parts which we order in to attempt recovery of a failed HDD.