The Tech Storror

Electronic commerce (E-commerce) Web based information system: An important component of modern computer based information system is web based information system. An information system based on the Internet is called a web-based information system. That is, when a user can use an information system through the Internet and the World Wide Web, that information system is called a web-based information system. A user of an information system on the Internet is called an Internet client. In this case, the client can use this information system from anywhere in the world by being connected to the Internet. Web based database is used in this system. When an Internet client sends an information request, the Web server verifies the client's right to receive the information in response to the request and sends the requested information to the client if it is a valid client. With the help of web based information system, the data of an organization can be collected, stored, presented, modern...

Control of power supply damage and its prevention Computers can have various problems related to power supply. Irregular supply of electricity is one of the problems related to computer power supply. Besides, not having proper voltage, frequent power supply, power return in shortest time interval, lack of earthing, fault in power supply unit, heating of internal parts of power supply unit, not getting proper voltage and signal at output power supply unit switch Not working mode etc. are some of the harmful regulators of power supply. All these problems and solutions are described below -- (a) Voltage problem : Damage to computers and other electrical appliances due to high voltage is a regular occurrence in our country. A voltage stabilizer can be used to avoid this condition. Many times when the voltage is much lower than required, any electrical appliance used in the home cannot be operated. In this case, the computer should be turned off. (b) Sudden power outage : Load shedding is a...

What are desktop items in Windows operating system\ Items on the Windows operating system desktop screen with names and pictures are each called icons. The main items on the desktop of the Windows screen are: (i) My Computer  (ii) My Network Place (ii) My Document (iv) Connect to the Internet (v) Online Service (vi) Recycle Bin (vii) Internet Explorer (viii) Taskbar (ix) Outlook Express Windows Media Player et cetera. The main items on the desktop of Windows operating system are described below-- Taskbar: The bar containing the text Start at the bottom of the desktop is called the taskbar. To the left of the taskbar is the Start button. From this button, various program files can be opened and the computer can be shut down. Besides, time and running programs are shown on the right side. My Document : Document and other files are saved in this folder as per default setting. Under My Document there is a sub-folder called My Picture. Any image input from a digital camera or scanner is...

Computer maintenance methods from controlling physical damage to computers Maintenance from dust and smoke: Computers can be damaged by dust as follows-- (i) Due to non-conductive coating of dust on various circuits, the heat generated in the circuit cannot be dissipated, resulting in damage to the circuit. (ii) Due to the formation of dust coating, the rotating components of the computer cannot rotate properly, resulting in various operational problems. (iii) Dust accumulation can damage the heads of disk drives. (iv) Cigarette ash dust can damage the data stored on the disk. The following steps can be taken to protect computer systems from dust:- (i) Computers should be properly cleaned at various time intervals. (ii) No smoking in the computer room. (iii) No powdered food should be consumed while sitting near the computer. (iv) Computers should not be placed where chalk is written on the blackboard. (v) The computer should be covered with a plastic cover. Maintenance due to temperat...

General features of printers General Features of Printer : Information stored in the computer's memory comes to the printer 8 through the input/output interface. The printer records incoming data permanently on paper. Hard copies of letters, numbers, symbols, images etc. are made with the help of printer. Printers with different features are manufactured by different companies. Following are some common features of the printer: (i) Print speed: Print speed (Print speed) means the speed of printing. That is, how fast, how much information can be printed out, this amount is used to measure. Print speed is expressed as DPI (Do Per Inch), PPM (Page Per Minute) etc. (ii) Print Quality: The print quality of the printer is called print quality. These print standards are based on four types of print. These are Draft Print, Letter Quality Print, Normal Print and Best Print. Generally, normal and best quality prints are available in laser printers. (iii) Buffer size: The amount of data that ...

Fundamentals of Digital Electronics Characteristics of Analog Signals and Digital Signals: Analog Signal: Continuous electrical signal is called an analogue signal. The change in analogue signal value over time is infinite. A simple signal-generating device converts physical quantities such as pressure, dip, light intensity, noise, etc. into equivalent analogue electrical signals through transducers. The value of this signal is always changing. That is, an electrical signal whose value continuously increases or decreases with time is called an analogue signal. The figure below shows the shape of an analogue signal: Digital Signal: The voltage level of the digital signal is isolated. The voltage level of a digital signal is expressed by two or more states. All these levels are expressed as low (Low) and high (High) or digital 0 volts. A discrete electrical signal is called a digital signal. The change in value of a digital signal with time is finite and the change in value is expressed ...

Analog Electronics (i) The branch of electronics technology that analyzes and discusses the design, construction, operational use, advantages, disadvantages, etc. of analogue signals and various circuits and devices operated by analogue signals is called analogue electronics. The branch of electronics technology that deals with digital signals, numbers and the design, construction, operation, use, advantages and disadvantages of various circuits and devices operated by digital signals. Various topics are analyzed and discussed, called digital electronics. (ii) Analog electronics systems use ever-changing electrical signals. Digital electronics systems have two defined levels of signals. (iii) Analog electronics are difficult to diagnose due to variations in signal. Since there are only two layers in the digital electronics system, fault diagnosis is easy. (vi) Signal processing circuit components are quite expensive in analogue electronics systems. Circuits used for signals in digital ...

Based on the interface, operating systems are divided into two categories, namely: (i) Text or character-based operating system (ii) Image-based operating system. Text or letter-based operating systems: In text-based operating systems, commands are executed by typing them in the command prompt according to their structure. Commands are written using letters, words, numbers, symbols, etc. To work in this system, the user needs to know the commands and syntax in advance and work by writing commands according to the syntax. Being color based this operating system is difficult and boring to work with. Commands have to be typed by keyboard only. A. Network, Internet system is not working. This system requires relatively little memory to operate, cannot run multiple programs simultaneously, supports only one user, and requires the use of a keyboard to move the cursor. No pictures, images or icons can be used in this command. Examples: MS-DOS, TOS, BOS, UNIX et cetera. Characteristics of tex...

Basic concepts of operating system The main purpose of the operating system is to-- • Creation of working environment: The operating system that creates a better working environment, the better and improved the operating system. • Coordinator: It coordinates between hardware and software. It acts as a coordinator between user tasks and all devices. • Automatic management: When a problem arises, it automatically understands what to do. If the appropriate solution is not provided, the operating system may automatically shut down the computer by itself. • Control of computer operations: The objective of the operating system is to control the speed of input/output operations by programs. • Memory management: helps the computer to work faster in stages by storing different files so that they can be found easily. this • Working based on priority: All the tasks that are directed to the computer are carried out based on priority. • Input/Output Management (I/O Management): It is the task o...

 Basic Concept on Data Security & Authentication Entity Level Security The security system is greatly strengthened by database authorization. Even then, security breaches do occur. Various unauthorized persons breach security through database misuse and accidents. But this is not desirable at all in case of database. Therefore, a security method called encryption is used in the database management system to further strengthen the security system. Data Recovery Database data is lost when the computer system fails or crashes due to any reason. The process by which this lost data can be recovered is called data recovery. Failures are of various types, namely-  (i) Transaction Failure (ii) Logical Error (iii) System Error  (iv) System Crash (v) Disk Failure Authorization Authorization is a process by which database security can be controlled. A database user can have different types of authorizations. This is dependent on database security. When the query processor transl...

Fundamental Operation of SQL SQL in data definition Data is defined or defined using SQL through the CREATE statement. An example is given below CREATE TABLE Employee() Emp_No NUMBER (5) NOT NULL Name CHAR (20) Skill CHAR (20) pay_rate NUMBER (10, 2); Explanation of the statement: (i) A table named Employee can be created through this SQL. The table will have four fields named Emp_No, Name, Skill and Pay_rate. (ii) Emp_No field will be NUMBER type data and this field will never be empty as it is declared as NOT NULL. (iii) Name field will be Character tight data and its length will be 20. (iv) The Skill field will be Character tight data and its length will be 20. (v) Pay_rate field will be NUMBER data type and its length will be 10 and 2 digits after decimal. Now let's say we want to add a new field to this table. Then type the following command: ALTER TABLE Employee ADD Phone_No NUMBER (10); Now type the following command to delete the Employee table. DROP TABLE Employee. SQL in ...

কম্পিউটার আর্কিটেকচার (Computer Architecture) কম্পিউটার ইঞ্জিনিয়ারিং-এ কম্পিউটার আর্কিটেকচার হচ্ছে কম্পিউটার সিস্টেমের কনসেপচুয়াল নকশা এবং কম্পিউটারের বেসিক অপারেশনের গঠন বিন্যাস। কম্পিউটার সিস্টেমে যে-সব বৈশিষ্ট্য প্রোগ্রামারের কাছে দৃশ্যমান অথবা প্রোগ্রামের লজিক্যাল এক্সিকিউশনের উপর যে-সব বৈশিষ্ট্যের সরাসরি প্রভাব আছে, তাকে কম্পিউটার আর্কিটেকচার বলে। উদাহরণস্বরূপ বলা যায় আর্কিটেকচারাল বৈশিষ্ট্যের মধ্যে আছে ইনস্ট্রাকশন সেট, বিভিন্ন ডাটাটাইপ রিপ্রেজেন্ট করতে ব্যবহৃত বিটের সংখ্যা, ইনপুট আউটপুট মেকানিজম এবং মেমরি অ্যাড্রেসিং-এর জন্য বিভিন্ন পদ্ধতি । কম্পিউটার আর্কিটেকচারের দুটি ধারা প্রচলিত আছে। একটি হলো হার্ভার্ড আর্কিটেকচার ও অপরটি ভন নিউম্যান বা প্রিন্সটন আর্কিটেকচার। আধুনিক কম্পিউটার আর্কিটেকচার (Modern Computer Architecture) আধুনিক কম্পিউটারের মৌলিক আর্কিটেকচার । হার্ভার্ড আর্কিটেকচার দ্বিতীয় বিশ্বযুদ্ধ চলাকালে হার্ভার্ড বিশ্ববিদ্যালয়ে এই আর্কিটেকচার নিয়ে গবেষণা করা হয়। হাওয়ার্ড আইকেন প্রথম এই আর্কিটেকচার প্রস্তাব করেন। দূরপাল্লার ক্ষেপণাস্ত্র নিয়ন্ত্রণে এই আর্কিটেকচার...

কাউন্টার (Counter) : যে লজিক সার্কিটের মাধ্যমে এতে প্রযুক্ত পালসের সংখ্যা গণনা করা যায় এবং গণনার ফলাফল বাইনারিতে প্রকাশ করা যায়, তাকে কাউন্টার বলে। সাধারণত ফ্লিপ-ফ্লপ সার্কিট দ্বারা এটি তৈরি করা হয়। কোনো কাউন্টারে যতটি ফ্লিপ-ফ্লপ ব্যবহার করা হবে, একে তত বিটের কাউন্টার হিসেবে ব্যবহার করা যাবে। কাউন্টারের সাহায্যে কম্পিউটারের অভ্যন্তরীণ কার্য সম্পাদন করা যায়। এ ছাড়া কাউন্টার সার্কিট ডিজাইনের মাধ্যমে বিভিন্ন যুক্তিমূলক কাজ করা যায় । উদাহরণস্বরূপ বলা যায়, ধরি একটা হলো রুমের আসন সংখ্যা ১০০টি। এতে এমন এক ধরনের কাউন্টার ব্যবহার করা যায় যা রমে প্রবেশকারী এবং রম পরিত্যাগকারীর সংখ্যা গণনা করে সার্বক্ষণিকভাবে খালি আসনের সংখ্যা বলে দিতে পারে এবং রমের আসন সংখ্যা পূর্ণ হলে তা খালি নেই বলে দিবে। কাউন্টারের ব্যবহার (Application of Counter) : কাউন্টারের ব্যবহার নিম্নরূপ___ (i) কাউন্টারের সাহায্যে কম্পিউটারের অভ্যন্তরীণ কার্য সম্পাদন করা যায়। (ii) কাউন্টার সার্কিট ডিজাইনের মাধ্যমে বিভিন্ন যুক্তিমূলক কাজ করা যায়। যেমন- ডিজিটাল ঘরিতে ব্যবহৃত হয়। (iii) অডিও/ভিডিও সিস্টেমে ব্যবহৃত হয়...

Register The register is a FF or memory element group, which works to store digital information together. It stores data in binary system. An FF can store one bit of digital data. The number of FFs needed to store a word depends on the number of bits in that word. For example, a group of 8 FFs is required to store a word of 8 bits. Thus, registers are groups of FFs or memory elements that work together to store digital information. In various digital systems, such as-  (i) Microprocessors of computers  (ii) Arithmetic and logic circuits.  Types of Registers: Registers are divided into different categories according to the type of work. Such as— (i) Temporary registers,  (ii) Flag registers,  (iii) General purpose registers are of 2 types based on providing inputs and outputs, namely—  (i) Serial and  (ii) Parallel. Four types according to data shifting or mode, namely : (i) SISO (ii) SIPO (iii) PISO (iv) PIPO Based on data shifting it is three types,...

Personal Information Manager: Personal information management is an important task for increasing office efficiency. People adopt various measures to manage this personal information. Eg: diary, notebook, electronic diary etc. People adopt these methods to perform the right task at the right time. Diaries are very important for managing many important information such as addresses, telephone numbers etc. Electronic diaries are now popular for personal information management. Various necessary information of daily life can be stored and used through this diary. Electronic diaries have a mechanism to signal the user for proper performance at specified times. Apart from that, many important information can be stored in the memory for future use through this diary. The work of personal information management can be done more easily through computers. A user's personal information can be neatly arranged through the large memory of the computer and various software. With the speed of co...

Introduction to Open Office: Open Source or the open software forum for all is publishing and promoting an integrated software called Open Office worldwide for free use by all. Open Office is a leading general office management software for word processing, spreadsheets, presentations, graphics, database etc., which increases office productivity manifold. This software can be downloaded and used completely free of charge with the facility of use on any type of computer in different languages. Current versions of Open Office software can easily import or export data or files used in other Office suites. Open Office has the facility to save documents or files in international open standard formats. This ensures the portability of OpenOffice files. Among the various programs in the OpenOffice.org suite are -- Their word processing program is called Writer.  And their spreadsheet analysis program is called Calc. The presentation program is Impress. The database program is Base. The pa...

Digital Office Management Basics and Elements: Basis of Digital Office Management The backbone of digital office management is the resource sharing network or connectivity through which various data and information can travel securely between each entity of the office. Office management can only be completed if information and flow can be ensured between each element of the office. A secure network is needed to ensure and secure office data flow. Networking refers to interconnected sharing of resources. Secure data sharing is considered the foundation of digital office management. To exchange this secure information, the network must also be secured. Components of Digital Office Management: The following 5 components or resources are required to create a modern office management system, namely (i) Hardware Resources (ii) Software Resources (iii) Data resources (iv) Network resources (v) Human resources. Human resource: The main component or resource of the office management system is...

Advantages of digital office management: (i) Constant communication of employees with the office: The main advantage of digital office management is that the office worker can always be connected to the office wherever he is. Any information can be provided at any time between each entity in the office. As a result, absence of a person from the office does not normally disrupt the functioning of the office. (ii) Non-inconsistency of data: In a traditional office environment, since the same information is written in multiple files, due to inconsistency, inconsistency or mismatch may be created between different data. For example, a regular customer's address has been changed in the sales section but not in the account section. There can be no data inconsistencies in digital office management. Because the authenticity and validity of the data is verified at various stages. (iii) Easier sharing and availability of data: There may be a need to exchange data between different department...

The word office is derived from the Latin word officium, whose Bengali term is office. Office in general sense is workplace, where people work. Office is needed to run the enterprise. Enterprise used to mean any business, venture or company, but now enterprise means large multinational corporations, universities, hospitals, research laboratories and government institutions, industries. And management means using information and communication technology and control systems to automate processes, so that minimal human intervention is required. Therefore, office management means the secretarial activities of the office through the application of information and communication technology (such as the preparation of necessary documents of the office, documentation and storage of documents, exchange of correspondence, internal and external communication, etc.) Also means done digitally. Automating routine office tasks is the main task of digital office management. Through digital office manag...

Electronic funds transfer is the transfer of money electronically through telephone and network. In this process, the amount of money is reconciled and modernized only through the account without exchanging the actual money between the accounts of different branches of the bank through electronic means. Banks use Automatic Teller Terminals or Machines (ATMs) for convenience and security in transactions. Bank cards with magnetic ink stripes are also used to perform bank transactions with data. Data is entered through a short key pad and inserted into the bank card terminal. Miniature video displays and printers are used for return signals. This card can be inputted in the bank or computer and can be withdrawn at any time of the day or night. The computer verifies the customer's signature, requiring no staff.