2 Introduction to C++ Programming and Graphics
pulse time of the computer circuitry, representing the highest attainable ideal
rate at which the computer can process information or execute an instruction.
The clock rate can be compared with the blood pulse of a living organism.
However, the clock rate is a meaningful measure of a processor’s efficiency only
when processors of a certain brand-name are compared side-by-side on the same
platform.
The CPU is able to receive data from an external memory bank, mani-
pulate the data as instructed, and send the result back to the data bank.
Transient information is stored in high-efficiency local memory units calledreg-
isters. The CPU communicates with other devices through information routes
implemented on buses.
Software
Instructions, parameters, settings, and other data are classified assoft-
ware. The instructions allow a computer to recognize the hardware, carry out
tasks, learn by experience, and exhibit artificial intelligence. Utility and ap-
plication software provides further functionality on a multitude of levels for
scientific, commercial, and entertainment applications.
The operating system
The most important piece of software is the operating system (OS). An
operating system is a program written in a mid-level language such as C or
C++, prescribing procedures and parameters that tell the computer how to
organize its physical components into logical units, manage the memory, and
communicate with the environment.
Examples of operating systems include the Unix system and its many
variations, the Windows OS, and the Mac OS. When a computer boots up, it
loads the operating system into memory from the recordable medium where it
resides, such as a hard drive or a CD-ROM.
The heart of an OS is its kernel. The Unix kernel is a very small portion
of the Unix operating system that allows it to run on many types of computers
- from personal computers running Linux, to supercomputers runningUnicos.
If something goes wrong, the kernel enters a panic mode.
BIOS
The basic input/output system (BIOS) is a small set of instructions
executed when the computer is first switched on. The BIOS is unrelated to the
installed operating system (OS), and is specific to the electronic hardware. Its
purpose is to activate the keyboard and monitor, and then run a small program