8-6
6. Continue moving the switch and writing down the alphanumeric display
readings for switch positions 4, 5, 6, 7, 8, and 9.
7. Return the switch to position 0.
Check the numbers you noted against the table below:
Switch
Current rev.
position
Code
as of January 1997
1
Video front end
9
2
AC3
3
3
System Services
8
4
Boot
0
5
Second stage loader
1
6
System Services baseline
8
7
Video baseline
9
8
AC3 baseline
3
9
Serial port ROM load
3
The software in the DA20 is subject to continual improvement, both at the factory and by
“dynamic loading” from film in the field. Therefore, the revision numbers for the
modules may be higher than those shown above, or lower for units made before the date
shown.
To confirm that you software is running normally you can “reboot” the system by
pressing the reset button located at the bottom of the Cat. No.673 card. If, when the
system boots, you see “C” and “r” go by rapidly, and “L” persist for a while before -
appears on the display, all is normal.
If you see “C” rapidly followed by “b”, before “–” appears on the display, the newer
versions of the code may have been corrupted and the system has loaded its baseline
code. In this case, any upgrades loaded from film will have been lost. If resetting the
DA20 does not cure the problem, the unit must be repaired. The dynamic loading process
may then have to be repeated, depending on the repairs carried out.
8.4
Starting and Program Loading
All computer- or microprocessor-based products have certain things in common. They
contain a computer of some sort, often with auxiliary input and output devices, and
various kinds of memory. Some kinds of memory are permanent and some forget all
when the power is turned off (volatile memory). When a product of this kind (as in the
DA20) is turned on, the first thing that happens is loading the non-permanent or volatile
memory with the programs stored in the permanent memory. Until this is finished, the
product cannot do anything useful. This process is called “booting,” or “re-booting.”
When this process is performed while the power is on, it is called “resetting,” or “warm-
booting.” “Cold-booting” simply means turning the power off and back on again.
