Source : Free On-Line Dictionary of Computing

same-day service
     
         An ironic term used to describe
        long response time, particularly with respect to {MS-DOS}
        {system calls} (which ought to require only a tiny fraction of
        a second to execute).  Such response time is a major incentive
        for programmers to write programs that are not {well-behaved}.
     
        See also {PC-ism}.
     
        [{Jargon File}]
     
        (1996-12-17)