Concisely describe the following terms 40 1. Source code 2. Object c.pdf
- 1. Concisely describe the following terms 40% 1. Source code 2. Object code 3. Compiler 4. Algorithm 5. Byte (used for what purpose) 6. Nano second or ns (used for what purpose) 7. System program (provide two examples) 8. Application program (provide two examples) 9. Preprocessing directive 10. ASCII Solution Answers: 1. A programmer writes a program in a particular programming language (ex : c , c++ ,java).This form of the program is called the source code. it can be read and easily understood by a human being. For example : Source code for Hello world program is: #include void main() { printf(“Hello World”); } 2. An interpreter or a complier translates source code into executable machine code. This machine code is called as the object code. Complier translates source code into object code. Object code contains instructions to be executed by the computer. 3. A complier is a program that translates a source program or source code written in particular programming language ( such as c , c++ or java ) into machine language (code). Example : Turbo c compiler. 4. Step –by- step instructions of a program is called is an algorithm. 5. 1 byte = 8 bits. A byte is a unit of measurement used to measure the data. Each byte represents a character. 6. A nano second or ns is a unit of time representing 10-9 or 1 billionth of a second. computer memory speed is represented in nano seconds.
- 2. 7. It is a type of computer program that is designed to run a computer’s hardware and application programs. Examples are : OS (operating system) BIOS Boot program. 8. Application program is a software program that runs on computer. Examples are word processors, web browsers. 9. Preprocessor directives are invoked by the complier to process some programs before compilation. Preprocessor directives are lines included in a program that begin with the character #. 10. ASCII: American Standard Code for Information Interchange) It is the most common format for text files in computers and on the internet. Short Answers: 1. Source code | Complier | Assembly code Assembler Libraries | Object code Link Editor | Executable code 2. a) Memory unit (storage) ALU (Arithmetic and Logical unit) CU (Control Unit) b) Storage: All the data to be processed and the instruction required for processing.
- 3. Intermediate results of processing. Final results of processing before these results are released to an output device. ALU (Arithmetic and Logical unit): It performs all the arithmetic operations (like addition, subtraction etc) and logical operations. CU (Control Unit): The control unit directs and controls the activities of the internal and external devices. 3. Fetch the instruction Decode the instruction Read the effective address Execute the instruction In executing the instruction Arithmetic and Logical unit (ALU) performs mathematical or logical operations .ALU sends a condition signal back to the control unit (CU). The result generated by the operation is stored in the main memory or sent to output device. Based on the Arithmetic and Logical unit feedback, the program counter (PC) updated to a different address from which the next instruction will be fetched. 4. Easy to learn. Easy to maintain. Easy to read and write. A program written in a high-level language can be translated into many machine languages and can run on any computer for which there exists an appropriate translator. i.e the language is independent of the machine on which it is used. Examples are c , c++ etc.