onstat -d flag

Has anyone got an idea what the flag 1001 is for a dbspace from the onstat -d command like the followingIts the flag set on dsa13. INFORMIX-OnLine Version 7.23.UC1 -- On-Line -- Up 02:00:38 -- 548776 Kbytes Dbspaces address number flags fchunk nchunks flags owner name 23c1c0ec 1 1 1 1 N informix rootdsa 23c1d27c 2 1 2 1 N informix dsa1 23c1d2e8 3 1 3 1 N informix dsa2 23c1d354 4 1 4 1 N informix dsa3 23c1d3c0 5 1 5 1 N informix dsa4 23c1d42c 6 1 6 1 N informix dsa5 23c1d498 7 1 7 1 N informix dsa6 23c1d504 8 1 8 1 N informix dsa7 23c1d570 9 2001 9 1 N T informix tempdb1 23c1d5dc 10 2001 10 1 N T informix tempdb2 23c1d648 11 1 11 1 N informix llogsdsa 23c1d6b4 12 1 12 1 N informix plogsdsa 23c1d720 13 1 13 1 N informix dsa8 23c1d78c 14 1 14 1 N informix dsa9 23c1d7f8 15 1 15 1 N informix dsa10 23c1d864 16 1 16 1 N informix dsa11 23c1d8d0 17 1 17 1 N informix dsa12 23c1d93c 18 1001 18 1 N informix dsa13 18 active, 2047 maximum Thanks Jim.