EBZ/DPM 11 April 98

                        On-Board Memory Pages
                        ---------------------

There are 20 pages of on-board memory, and 3 types of memory: 
        Type 1 - Memory Page -> with 2.125 MB of RAM
        Type 2 - List Memory (successive memory - listed in order) -> this
                 contains 8 bytes of data and 2 bytes of error code
                 (to store large amounts of data at a time)
        Type 3 - Table Memory (lookup tables) -> this contains 2 bytes of 
                 data and 1 byte of error code (to be accessed one at a time)


Pages                   Use
------------------------------------------------------------------------
0       Receive data from camera        F1-F3 data
1       Receive data from camera        F2-F4 data 
2       Receive data from camera        F1+F2+F3+F4 data
3       Receive data from camera        4xFc Sum of all continuum images
4       Temporary storage of just image, not header or other info
5-7     velocity, continuum, line depth images stored here after construction
                but before compression
8       Primary downlink page - velocity map is compressed and downlinked 
9       Secondary downlink page - second observable is compressed and downlinked
10      List memory - backup flat field stored
11      Scratch page (for in-between stages)
12      List memory - flat field storage
13      Magnetogram stored during structure program
14      List memory - compression binning tables and time-weighted averages stored
15      Magnetogram stored during structure program
16      Table memory - ip registers and Velocity/Reciprocal/Sqrt compression tables stored
17      Magnetogram stored during structure program
18      Magnetogram stored during structure program
19      Magnetogram stored during structure program


When in campaign mode, the magnetograms are not stored on-board and are made in
page 7 and immediately downlinked in page 8.

Data is taken, placed in pages 0-3, is moved to 4, goes to 5-7, goes to 14-16,
then goes to 8/9 to be downlinked

Pages 10,12,14,16 have back-up power systems (keep-alive power).