code: protected void reserve(long reservedDelta)
                      throws ObjectManagerException
      {
  
          if (Tracing.isAnyTracingEnabled() && trace.isEntryEnabled())
              trace.entry(this, cclass,
                          "reserve",
                          new Object[] { new Long(reservedDelta) }
                              );
          long unavailable = reserveLogFileSpace(reservedDelta);
          if (unavailable != 0) {
              if (Tracing.isAnyTracingEnabled() && trace.isEntryEnabled())
                  trace.exit(this, cclass,
                             "reserve",
                             new Object[] { "via LogFileFullException", new Long(unavailable), new Long(reservedDelta) }
                                  );
              throw new LogFileFullException(this
                                             , reservedDelta
                                             , reservedDelta
                                             , reservedDelta - unavailable);
          } // if (unavailable != 0).
  
          if (Tracing.isAnyTracingEnabled() && trace.isEntryEnabled())
              trace.exit(this,
                         cclass,
                         "reserve");
      }
docs: Reserve space in the log file.
  We don't have to account for sector bytes because those were reserved at startup.
  
  @param reservedDelta the change to the number of reserved bytes if this write is successful.
  @throws ObjectManagerException