Q6.7: How do I check if log truncation is blocked?

select h.spid, convert(varchar(20), h.name), h.starttime
  from master..syslogshold h, sysindexes i
 where h.dbid = db_id()
   and h.spid != 0
   and i.id = 8 /* syslogs */
   and h.page in (i.first, i.first+1)/* first page of log = page of oldest xact */