They had data, but did not bother to watch it or (apparently) even trasmit it to ground or cockpit. It appears this was data that was considered to be of secondary value - valuable to a select few engineers/analysts after the flight but considered to be non-essential for normal flight.
It sounds like a bunch of sensor data was processed in a very basic form and simply 'laid onto magnetic tape' - there are special 'data recorders' that will take simple voltage data from, say, a 'thermistor' (used as a simple temperature sensor) or strain guage and simply record it for later review ...
"It sounds like a bunch of sensor data was processed in a very basic form and simply 'laid onto magnetic tape' -"
This craft was instrumented with a lot more sensors than the others because these were embedded at build time for performance analysis on the early vehicles.
Most of this extra sensors and the wires to support them were torn out (saveing 7000 bounds (or was it kilos) of vehicle weight.
According to nasa, only those few sensors that were hard to get to were left in place. (This per one of the televised briefings a month ago).
Im speculating thats where these measurements came from.