"DH" on Raf service number index cards?

**Beagletorque** · 27th December 2021, 11:27

Does anyone know what the "DH" stands for?

**Ross_McNeill** · 27th December 2021, 11:31

As far as I'm aware - its mostly on post war entry and was an administrative check sum to ensure correct service number recording.

Ross

**Beagletorque** · 27th December 2021, 11:43

Thanks Ross.

Does it indicate death in service?!!

I can't find anything of him anywhere!

**Ross_McNeill** · 27th December 2021, 12:23

No.

The hollerith cards had been used for equipment tracking during the war and post war the service record index system ran in two formats.

Record of Service file in Registry under service number

and

Card Index under name and service number.

If a service number was incorrectly entered when the hollerith card was created it had massive repercussions.

To that end when the card index was created a two character checksum was generated which should match the hollerith card when it was created.

Not an exact match digit for digit just a trip wire as in modern Cyclic Redundancy Checks on computer data packets today to say that information was possibly corrupt.

As the two character was never amended on any index card it must remain valid and the only piece of info that does not change unless service changed is service number.

Ross