bare metal
n. 1. New computer hardware, unadorned with such
snares and delusions as an operating system, an HLL, or
even assembler. Commonly used in the phrase `programming on the
bare metal', which refers to the arduous work of bit bashing
needed to create these basic tools for a new machine. Real
bare-metal programming involves things like building boot proms and
BIOS chips, implementing basic monitors used to test device
drivers, and writing the assemblers that will be used to write the
compiler back ends that will give the new machine a real
development environment. 2. `Programming on the bare metal' is
also used to describe a style of hand-hacking that relies on
bit-level peculiarities of a particular hardware design, esp.
tricks for speed and space optimization that rely on crocks such as
overlapping instructions (or, as in the famous case described in
The Story of Mel, a Real Programmer (in Appendix A),
interleaving of opcodes on a magnetic drum to minimize fetch delays
due to the device's rotational latency). This sort of thing has
become less common as the relative costs of programming time and
machine resources have changed, but is still found in heavily
constrained environments such as industrial embedded systems, and
in the code of hackers who just can't let go of that low-level
control. See Real Programmer.
In the world of personal computing, bare metal programming
(especially in sense 1 but sometimes also in sense 2) is often
considered a Good Thing, or at least a necessary evil
(because these machines have often been sufficiently slow and
poorly designed to make it necessary; see ill-behaved).
There, the term usually refers to bypassing the BIOS or OS
interface and writing the application to directly access device
registers and machine addresses. "To get 19.2 kilobaud on the
serial port, you need to get down to the bare metal." People who
can do this sort of thing well are held in high regard.
