COMPUTER BASICS

Computer's CPU contains necessary circuitry for data processing and controlling other components of the computer. However, one thing it does not have built into it the to store programs and data needed during data processing. The CPU contains several registers for storing data and instructions but they can store only a few bytes at a time. They are just sufficient to hold one two instructions with corresponding data. If instructions and data of an executing program were to reside in secondary storage like a disk, and fetched and loaded one by one into CPU registers as the program execution proceeded, this would load the CPU being idle most of the time. This is because there is a large speed mismatch between the rate at which CPU can process data and the rate at which the system can transfer data from disk to CPU registers. For example, a CPU can process data at a rate of above 5 nanoseconds/byte and a disk reader can read data at a speed of about 5 microseconds/byte. Hence, within

 Database oriented approach of Organising data provides a set of programs to facilitate users to organise, create, delete, update and manipulate data in a database. All these programs together form a Database management system ( DBMS). Features found commonly in database management system are described below : Database models: We saw that database integrates together multiple related files. A database model defines the manner in which a database links it's various data elements tougher. Four database models used commonly are, hierarchical, network, relational, and object oriented. Also known as database structure techniques, they are described below.   1. Hierarchical Database: A hierarchical database links it's data elements as an inverted tree structure ( root at the top with branches formed below). Below the single root database element are subordinate elements, each of which, in turn has its own subordinate elements and so on, the can grow to multiple levels. Database eleme

 File oriented approach of Organising data provides a set of facilitate users to organise, create, delete, update, and manipulate their files. All these programs together form a File management system (FMS). Features found commonly in file management system are described below: File types We categorize data files according to the way an application uses them. A file management system typically supports following types of files: 1. Transaction file: A transaction file stores input data until the application uses it during next Processing cycle. For example, in a payroll application for generating monthly pay slips of employees, current month transaction file contains this month's data of each employee, such as details of hours worked, normal and overtime hours, and if peace work is involved, quantity of goods made. 2. Master file: A master file contains all current data relevant to an application. For example, in payroll application mentioned above, master files contains payment det

  Spreadsheet with is a numerical data analysis tool that allows us to create computerized ledger. A manual ledger is a book having rows and columns that accountants use for keeping record of financial transactions and preparing financial statements. Accountants use pencil, erasure, and hand calculator to prepare financial statements using manual ledger. This is a tedious task and often takes a long time to come out with an acceptable and satisfactory financial statement, due to several  iterations of formula calculations, and making it easier to change certain numerical values and seeing the effect of these change across the worksheet (ledger) immediately. With the availability of spreadsheet Packages, we are no longer required to use pencil, erasure, and hand calculators for dealing with tasks that require numerical data analysis.

 Although we can design a computer to make it understand many different computer languages, every computer understands only one language without using translation program. This language is called machine language of the computer. normally, the machine language of the computer is written as the strings of binary 1s or 0s. The circuitry of a computer can recognize the machine language instructions immediately. It converts them into electricals signals to execute them. A  machine language instruction has the two part format. The first part is operation code that tells the computer what function to perform, and the second part is operand that tells where to find or store the data on which the computer has to perform the function. hence, each instruction tells the computer what operation to perform and the length and locations of the data fields involved in the operation. every computer has a set of operation codes called its instruction set. Each operation code in the instruction set is me

  This chapter continues with the discussion of development of computer programs. Once a programmer has finished planning of a computer program, he/she is now ready to write the steps of the corresponding algorithm in a programming language.  Computer language or programming language is a language acceptable to a computer system, and the process of writing instructions in such a language is called programming or coding.   The goal of this post is to introduce some popular programming languages.  Analogy with natural languages:   Language is a mans of communication. We use a natural language such as English, to communicate our emotions and ideas to others. Similarly a programmer uses a computer language to instruct computer what he/she want to do.  All natural languages (English, French, German, etc.) use a standard set of words and symbols for communication. Everyone uses that language understands these words and symbols. The set of words allowed in a language is called its vocabulary.

Two standard methods of organising data for data processing applications are file oriented approach and database oriented approach. File oriented approach was traditional method used in early days of data processing. It has been replaced today largely by database oriented approach. However, several applications, dealing with simple and small data sets, use file oriented approach, even today. Hence, both these methods are described below. File oriented approach: This method organizes an application's data into one or more files and the application program processes the data stored in these files to generate desired output. For example, it is customary to use a master file of permanent ( and, usually, the latest) data, and transaction files containing data of temporary nature. For instance, in a pay roll application, in additional to containing all permanent details of each employee ( name, address, employee code, pay rate, income tax rate, etc.) master payroll file also contains cur

  Data Processing  -  Data is collection of facts - unorganized, but able to organized into useful information. A collection of sells orders, employee time sheets, and class attendance cards are a few examples. We can manipulate data to produce output, such as bills, employee salary slip, and student attendance reports. This output, called information, is organized facts that help people to make decisions. Hence, information is data arranged in an order and from that is useful to people who receive it. Processing, in general terms, is a series of actions or operations that coverts some input into useful output. In data processing, input is data, and useful output is information. Hence, Data processing is a series of actions or operations that converts data into information.   It consists of three sub activities -  Capturing input data. Manipulating input data. Producing output information. Data processing system consists of  resources such as people, procedures, and devices, which is u

Processor :  A processor is an integrated electronic circuit that performs the calculations that run a computer. A processor performs arithmetical, logical, input/output (I/O) and other basic instructions that are passed from an operating system (OS). Most other processes are dependent on the operations of a processor. The terms processor, central processing unit (CPU) and microprocessor are commonly linked as synonyms. Most people use the word “processor” interchangeably with the term “CPU” nowadays, it is technically not correct since the CPU is just one of the processors inside a personal computer (PC). Types of processor : 1. CISC Processor 2. RISC Processor 3. EPIC Processor 4. Multicore Processor 1. CISC :  A complex instruction set computer is a computer in which single instructions can execute several low-level operations (such as a load from memory, an arithmetic operation, and a memory store) or are capable of multi-step operations or addressing modes within single instructio