[vdr] what are section filters?

hi.

since i get many lines of

read incomplete section - len = 1127, r = 334

when my machine is recording and under heavy CPU load, i was curios what this means. i had a look at the vdr source and saw that there is nearly no code to recover from short reads from the corresponding filedescriptor. my guess is, that this data is not important enougth to be handled more carfully. but what is it for? i searched the web for EIT DVB section filters a.s.o. but couldn't find any useful information. can anybody give me some hints or point me in the right direction regarding section filters?

thanx ... clemens