I was grateful to discover the MARC 306 field at the recent KLAS Users Conference.
If you don't know, the 306 field shows a numerical representation of the runtime also shown in the 300 field (aka Alt Length). So, if the Alt Length (MARC 300 field) reads "6 hours, 9 minutes" the 306 field reads "\\$a060900" (hour-hour-minute-minute-second-second). Knowing this format allows you to query for long books/short books. Pretty cool!
My questions are:
(1) How/When is the 306 field created? Is it calculated from the 300 field? Does Keystone manually add it or does the NLS provide it in the full MARC records?
(2) If I manually copy the runtime from say BARD and paste it into the Alt Length field (MARC 300 field) will I break or prevent the creation of the 306 field? Sometimes the Alt Length field sits null/empty for a long time and I feel inclined to fill it in, but I increasingly wonder if I'm doing harm to the 306 field.
