ill-behaved

ill-behaved
 adj.

   1. [numerical analysis] Said of an algorithm or computational method
   that tends to blow up because of accumulated roundoff error or poor
   convergence properties.

   2. [obs.] Software that bypasses the defined {OS} interfaces to do
   things (like screen, keyboard, and disk I/O) itself, often in a way
   that depends on the hardware of the machine it is running on or which
   is nonportable or incompatible with other pieces of software. In the
   MS-DOS world, there was a folk theorem (nearly true) to the effect
   that (owing to gross inadequacies and performance penalties in the OS
   interface) all interesting applications were ill-behaved. See also
   {bare metal}. Oppose {well-behaved}. See also {mess-dos}.

   3. In modern usage, a program is called ill-behaved if it uses
   interfaces to the OS or other programs that are private, undocumented,
   or grossly non-portable. Another way to be ill-behaved is to use
   headers or files that are theoretically private to another
   application.
    

ill-behaved

   1. [numerical analysis] Said of an {algorithm} or
   computational method that tends to blow up because of
   accumulated roundoff error or poor convergence properties.

   2. Software that bypasses the defined {operating system}
   interfaces to do things (like screen, keyboard, and disk I/O)
   itself, often in a way that depends on the hardware of the
   machine it is running on or which is nonportable or
   incompatible with other pieces of software.

   In the {IBM PC}/{mess-dos} world, there is a folk theorem
   (nearly true) to the effect that (owing to gross inadequacies
   and performance penalties in the OS interface) all interesting
   applications are ill-behaved.

   See also {bare metal}. Opposite: {well-behaved}, compare
   {PC-ism}.

   [{Jargon File}]