The CCW trace confirms it: it's VM/370 purposely doing it, and it does indeed
appear to be some type of printer device initialization sequence that it's only
performing when VM's real physical printer is first started for the very first
time after an IPL.
Not true. Its possible to generate multiple "FF" characters in a print file. It appears to be when you tell CP to START a printer, so commence printing from the Spool.
So a DRAIN and START, or a simple START with a different class will both generate the "FF" character in the data stream.
I assume this is because in between the printer could have been attached to a VM such as DOS or MVS.
Dave
