How does a Computer Program Work - Research Paper Example

How Does A Computer Program Work? Personal Computers (PCs) trace their history back to the 1970s when Ed Roberts began to sell computer kits that were based on a microprocessor chip. These were designed by Intel and so Intel is undoubtedly the flag bearer of the PCs that we see today. They have evolved immensely over time yet the main components stay unharmed. The first commercial PC was the Altair 8800 and it sold for a nominal price of 395usd (Parsons, June). Ever since, PCs have been popular and now we have laptops, notebooks and tablets which are compact versions of the same thing. PCs are an agglomeration of many different components that are geared to achieve the same goal which is to allow the user to perform tasks on the computer and get the desired results. PCs are used in all households by more or less all members of the family; from the 5 year old son who tries to learn the alphabets to a 90 year old granny who uses it to pass time while everyone else has gone for work. Whether a PC is used for typing a word document or sending emails or browsing the internet, it does a lot more functions than we speculate (White, Ron). These functions are carried out at a nanosecond level so when we work on a PC we never get delays despite all the functions being carried out inside a PC. When we look at a computer, we see the basic parts which include the Central Processing Unit (CPU) or the PC tower in layman terms, a monitor or a screen, a keyboard and a mouse. We may have other peripherals such as a webcam, printer, speakers etc but these are not the basic components that help in the smooth running of the computer. What happens when we send a command to the computer is one question that all PC users would have in mind. The command can be a computer program, a simple click, a typed word or anything for that matter. In order to understand the whole process, we need to define some other components that lie within the CPU which is the brain of the computer. The CPU is the control center of the computer and it is here that all data input which comes from the keyboard gets modified and processed so that we could get our desired output. The CPU contains very extensive circuitry that is used in the execution of the stored program instructions. The CPU contains two parts, the processing unit and the memory (Young, Roger). The processing unit can be further classified into the arithmetic/logic unit and the control unit. The control unit does not execute the program but it directs the other parts of the system to do so. When a command is sent, it first goes to this control unit which then directs it to the unit which will eventually execute the program instructions. Thus the control unit has a vital role to play in the execution of the program. ALU or most commonly known as the arithmetic and logic unit has two parts, the arithmetic unit and the logic unit. The arithmetic unit is designed so that it completely deals with any numeric data that the computer receives. It is capable of executing additions, subtractions, multiplications, divisions and all other complex mathematical functions. However, any functions, arithmetic or non arithmetic are carried out in binary language inside a computer. When we send information to the computer by pressing a key of the keyboard the computer in fact gets its ASCII value which is later converted to binary so that the desired operations may be carried out. The decoder converts it to binary and then carries out the operation. The logic unit performs any comparisons that are sought for, if the user wants to know which of the two numbers is greater or smaller or if the two numbers are equal the command is sent to the logic unit. The logic unit compares and again gives its answer in binary, 1 for yes and 0 for no. The computer may however be designed in a way that it deals with opposite logic. Once the control unit sends the information to the ALU and the ALU executes the program it needs memory space so as to receive, hold and transmit data. If it will use the memory allocation of the CPU itself, it would take a long time in the execution and also it will result in the memory being full very soon. So to avoid the trap, we have registers. Registers provide temporary storage of data. They make sure that the speed of the computations is not compromised as it would have been if the memory was used instead. Once the information is processed and ready it is sent back to the control unit. Now the control unit needs to decide whether it is to be stored in the memory location in which case it goes to the memory or does it simply have to be displayed in which it goes to the desired output device which is most commonly the monitor. Memory of a computer is in the form of Random Access Memory (RAM) and Read Only Memory (ROM). The memory of a computer is used to hold data and instructions for processing. It is used to store the program instructions or the data for as long as the program is being carried out. When memory space is to be allocated the control unit sends the data to the memory space where it is given an address location. The RAM is designed so that it can randomly access all memory locations within it. It is inside the RAM that all application programs and the data that is in use are stored so that they can be quickly accessed by the processor of the computer when needed (Appleman, Dan). RAM allows very fast access to instructions and data. ROM on the other hand, is the read only memory. It contains data that has been written by computer manufacturers. No more data can be written on to the ROM since it would require burning the ROM again and neither can data be erased from the ROM since it requires exposing it to ultraviolet radiations. Most PCs contain a very small capacity of ROM which is used to store critical programs like programs that boot the computer or that are used in its everyday working and are essential to it. For storage PCs use registers, RAM, ROM, floppy disks and hard disks. There are different languages that can be used in order to perform certain programs inside a computer. For instance Java, C++, Python and Matlab are some of the most fundamental languages that a user may use to write his program. A program is just a set of instructions using a syntax that the computer understands. There are some assembly level languages that deal in binary numbers for example C while there are some higher level languages like Perl that use a syntax that is much easier to understand by humans. These languages just provide us a way to let the computer know what we are expecting out of it (Buyens, Jim). Programming is thought to be a difficult job since it is not just talent, it comes with practice. To sum it up, a computer is a very systematic device made up of many components, each one doing its part of the job and giving information to the next part. These parts form a chain and in the end, we get our desired result. References White, Ron (2005). How Computers Work. Que. Young, Roger (2009). How Computers Work: Processor and Main Memory. CreateSpace. Appleman, Dan (2000). How Computer Programming Works. Apress. Buyens, Jim (2002). Faster Smarter Beginning Programming. Microsoft Press. Parsons, June and Oja, Dan (2009). Computer Concepts. Course Technology. Read More