I am trying to understand what this limit actually means?
(https://www.salesforce.com/us/developer/docs/apexcode/Content/apex_gov_limits.htm#static_gov_limits_section) states "Maximum size of callout request or response (HTTP request or Web services call)1" cannot be over 3MB. 
I just implemented a Java service using the Partner WSDL that had no issues extracting a 6.8MB file. It ran into Heap size errors for an attachment size of 16.8MB, but I'm guessing if I increase the heap space at run time, this issue would also get rectified. 
So does this mean the limit only applied to data extracted using SFDC's Apex HTTPRequest and HTTPResponse objects? Is there even a limit to the size of file I can extract using a Java client external to SFDC?

Here is part of the subroutine:

        my $self       = shift;
        my $changelist = shift;
        my $sObject_type = 'ADM_Work__c';

        if( $self->{_p4status} eq $GUS::OPEN_ONCE ) {

            print "\n\n ----------------------------------------------------------------------\n";
            print "$sObject_type, id => " . $self->{_id} . ", Perforce_Status__c => $GUS::NONE)";
            print "\n\n ----------------------------------------------------------------------\n";

            my $result = $self->{_sfdc}->update(type => $sObject_type, id => $self->{_id}, Perforce_Status__c => $GUS::NONE);
           
            if ($result->valueof("//updateResponse/result/success") ne 'true') {
                # log problem here
                print "unable to update p4 status";
            } else {
                $self->{_p4status} = $GUS::NONE;
            }
       
Here is the output:
 ----------------------------------------------------------------------
ADM_Work__c, id => a0HT0000000KIZbMAO, Perforce_Status__c => --None--)

 ----------------------------------------------------------------------
Type looks to be getting set from the print statement output??