Death Code N.
A Routine Whose Job Is To Set Everything In
The Computer -- Registers, Memory, Flags, Everything -- To Zero,
Including That Portion Of Memory Where It Is Running
A routine whose job is to set everything in
the computer -- registers, memory, flags, everything -- to zero,
including that portion of memory where it is running; its last act
is to stomp on its own "store zero" instruction. Death code
isn't very useful, but writing it is an interesting hacking
challenge on architectures where the instruction set makes it
possible, such as the PDP-8 (it has also been done on the DG Nova).
Perhaps the ultimate death code is on the TI 990 series, where all
registers are actually in RAM, and the instruction "store
immediate 0" has the opcode "0". The PC will immediately wrap
around core as many times as it can until a user hits HALT. Any
empty memory location is death code. Worse, the manufacturer
recommended use of this instruction in startup code (which would be
in ROM and therefore survive).
orthogonal: [from mathematics] adj. Mutually independe well
separated; sometimes, irrelevant to. Used in a generalization of
its mathematical meaning to describe sets of primitives or
capabilities that, like a vector basis in geometry, span the
entire `capability space' of the system and are in some sense
non-overlapping or mutually independent....
orthogonal adj.
[from mathematics] Mutually independe
well separated; sometimes, irrelevant to. Used in a generalization
of its mathematical meaning to describe sets of primitives or
capabilities that, like a vector basis in geometry, span the entire
`capability space' of the system and are in some sense
non-overlapping or mutually independent....
