Lexmark C752 Technical Reference page 233

setfileposition
moves the read pointer in an open file to the new specified file position. This is
defined as the number of bytes from the start of the file. The next read operation
starts at the new file position. This operator is in systemdict.
Errors: ioerror, stackunderflow, typecheck, undefinedfilename
Note: An undefinedfilename error occurs if the file does not exist.
sethardwareiomode
is parsed and discarded. In addition, one integer is removed from the stack. It
supports compatibility with the IBM LaserPrinters 4019, 4029, and 4039.
Errors: invalidaccess, stackunderflow, typecheck
setidlefonts
supports compatibility with the IBM LaserPrinters 4019, 4029, and 4039. It is
parsed and pulls items from the stack until a mark is reached.
Error: unmatchedmark
setignoresize
See page 4-12.
4-50
PostScript