Hi everybody,
Thank you in advance for your advice :).

We are currently mapping data from a legacy collection descriptive system 
to one that will comply with EAD and EAC standards. 

I have a query about describing the duration of oral history interview 
tape recordings, and would be very grateful for some clarification from 
the group.

So, in our Oral History & Sound collection data, current measures include 
Quantity, Number of Interviews, and Duration. Quantity is currently an 
integer, plus a lookup list for ‘type’, plus a space for free text. We are 
retaining this and have mapped the elements fairly straightforwardly to 
<physdesc> <extent><unit>, <physdesc> <extent type="[value]">, and 
<physdesc> <extent>. Number of Interviews is an integer and we have mapped 
it to <physdesc> <extent><unit>.

Our field Duration contains a number only, representing number of minutes. 
At first take we had mapped it to <materialSpec>, as the Preface to the 
EAD tag library states “Information such as scale for technical drawings 
and maps and playing time for sound recordings can be expressed in 
<materialspec>”, and the <materialspec> tag description includes “… 
physical presentation data for music records”.

However we feel that Duration may also be usefully mapped to Extent, and 
note that the <extent> tag library includes “…the volume of a data file in 
bytes”, which we feel may be comparable. 

I would really appreciate any experience or clarification others can offer 
in this area please?

Thanks,
Nicola

Nicola Frean | Leader, Arrangement & Description
Alexander Turnbull Library, National Library of New Zealand
PO Box 12349
Wellington
NEW ZEALAND
DDI: +64 4 4623903
http://natlib.govt.nz/