EN Free Space Command 16-21
Free Space Command 
The Free Space command returns the amount of available memory. 
This response returns two values: the total available memory, and 
the largest available block of memory (refer to the “Memory Status 
Response” section later in this chapter for additional information).
E
C
 * s 1 M
If a value other than 1 is sent, this command returns an error 
(“ERROR = INVALID UNIT,” refer to “Memory Error Response” 
section later in this chapter for additional information).
To identify whether the printer has enough memory available for a 
job, you can send the Free Space command to compare the space 
available with that needed. You can also identify how much memory 
an entity or any other data uses by checking the amount of free 
memory prior to downloading the data, then downloading the data, 
and checking memory again. The difference in these values 
represents the approximate memory needed.
Note Many conditions can cause the available memory to change or 
appear different. Some of these conditions are listed below.
The actual printer memory required to store an item varies slightly 
based on printer memory fragmentation and other internal printer 
conditions.
Different printer models use different methods to store data. Thus, the 
amount of memory required to store the same amount of data may be 
slightly different in different printers.
While the printer is processing page data, the available memory is 
constantly changing due to the printer receiving new data, processing 
existing data, and adding new characters to the font cache, etc. Under 
these conditions, the available memory may change by the time the 
memory response is returned.
If a PostScript SIMM is installed in the printer, some memory is not 
reported for a Free Space command response. This memory is not 
reported as part of the free memory for a PCL status readback 
response, however, this memory is available for PCL use. Thus, it is 
possible for all or part of the downloaded data to be stored in this 
section of unreported memory and not change the memory response 
size.