Rockwell Automation 9323-S5500D A.I. SERIES MICROLOGIX 1000 AND PLC-500 SOFTW - Manual (Page 447)

MicroLogix 1000 and PLC-500 A.I. Series Software Reference
19-16
Free Memory: Free bytes of extended memory available for use by PLC-500
A.I. and virtual memory, which includes the amount of space
available for swapping to disk.
Free Disk Space: The number of bytes available on the current drive.
3. To go back to the ladder editor, press any key.
The last line on the screen displays the system date and time, and the serial number of
your Rockwell Software product.