What are "S???????.DTF" files?

In my domino directory on a 6.0.2CF1 server I have numerous of these 
files:
...
S8241229.DTF
S8242633.DTF
S8243125.DTF
S8247663.DTF
S8252172.DTF
...

What are they?

V5R2,
cume=TL03161
WRKPTFGRP
PTF Group             Level
SF99519                  71
SF99502                   8
SF99271                   9
SF99190                  10
SF99169                  13
SF99149                   3
SF99148                   3
SF99098                  10
SF99085                   6
SF99039                   2


ps:  The server they are on is locked up now and there are no nsd* files. 
The ps I am going to open up a Notes incident on.
Subsystem/Job  User        Type  CPU %  Function        Status
DOMINO01       QSYS        SBS      .0                   DEQW 
  EVENT        QNOTES      BCI      .0  PGM-EVENT        SELW 
  QNNINSTS     QNOTES      BCH      .0  PGM-QNNINSTS     EVTW 
  SERVER       QNOTES      BCI      .0  PGM-SERVER       SELW 

09/15/2003 02:04:06   Completed consistency check on admin4.nsf  
  
Fatal Error signal=0x00000001 JOB=SERVER/QNOTES/080745 
PID/TID=3505/0x00000
092  
***************************** DEBUG BREAKPOINT 
***************************** 
  
JOB: 080745/QNOTES/SERVER    THREAD: 0x92  
GetNSModifiedTime                                     8     LOOKUP 
LIBNOTES 
...


Rob Berendt
-- 
"They that can give up essential liberty to obtain a little temporary 
safety deserve neither liberty nor safety." 
Benjamin Franklin