HP PCL/PJL reference (PCL 5 Printer Language) - Technical Reference Manual Part I

EN Free Space Command 16-23
“LARGEST=” identifies the largest continuous block of available
memory (in bytes).
An example response is shown below:
PCL
INFO MEMORY
TOTAL=100000
LARGEST=25000
The above example indicates that the printer has 100,000 bytes of
available memory and the largest continuous block is 25,000 bytes.
Memory Error Response
If the Free Memory command value field is out of range (not 1),
then the memory status response returns an invalid unit error. For
example, if the Free Space command with a value of 2 (
E
C
*s2M)
were sent, the following error would be returned:
PCL
INFO MEMORY
ERROR=INVALID UNIT