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The main aim of system programming is to design of system software and to provide basic for judgment in the design of software. And we will do it through discuss of design and implementation of the major system component.
Computers are basically machines that follow very specific and primitive instructions. Earlier day’s people gave instructions to machines through on and off switches. Later people gave instructions like X=3; Y=4; what is X+Y and so on. But computer now a day’s cannot understand such languages with the aid of some program which are called as system programs. System program (i.e. compiler, loader, macro processors, operating system) were developed to make the computers better adapt to needs of the users. And later on people wanted more assistance in the mechanisms of preparing their programs. This is what gave rise to system programming.

• Compilers are system programs that accept people-like language and translate them into machine language.
• Loaders are system programs that prepare machine language programs for execution.
• Macro processors allow programmer s to use abbreviations.
• Operating systems and file systems allow flexible storing and retrieval of information.

Memory is the device where information is stored.

Bits are the unit of storage that may be either one or zero.

Data or instructions are the content of words. A processor performs these instructions that are stored in memory. Thus instruction and data share the same storage medium.

Programs are sequence of instructions.

Codes is a set of rules for interpreted groups of bits i.e. codes for representation of decimal digits (BCD), for characters (EBCDIC, or ASCII).

Processors are the devices that operate on this information. There are two types of processors i.e. Input/Output (I/O) processor that are concerned with transfer of data between memory and peripheral devices such as disks, drums, printers and typewriters where as the Central processing unit (CPU) is concerned with the manipulation data stored in the memory. The I/O instructions are stored in the memory that is activated by the command from the CPU