Assignment Discovering Computer 2011 - Chapter 10 Database Management

Assignment from Mr. Tri Djoko Wahjono, Ir., M.Sc.

Name : Tommy Hendrawan

NIM / Class : 1701309513 / 01PCT

Assignment : Discovering Computer 2011 - Chapter 10 Database Management

1. What Is a Database, and How Does a Database Interact with Data and Information?

A database is a collection of data organized in a manner that allows access, retrieval, and use of that data. Database software, often called a database management system (DBMS), allows users to create a computerized database; add, modify, and delete the data; sort and retrieve the data; and create forms and reports from the data. Data is a collection of unprocessed items, which can include text, numbers, images, audio, and video. Computers process data into information. Information is processed data; that is, it is organized, meaningful, and useful. In addition to documents, information can be in the form of audio, images, and video.

2. What Is Data Integrity, and What Are the Qualities of Valuable Information?

Because data is used to generate information, many organizations realize that data is one of their more valuable assets. Data integrity identifies the quality of data. Data integrity is important because computers and people use information to make decisions and take actions. For a computer to produce correct information, the data that is entered in a database must have integrity. For information to be valuable, it should be accurate, verifiable, timely, organized, accessible, useful, and cost-effective. Accurate information is error free. Verifiable information can be proven as correct or incorrect. Timely information has an age suited to its use. Organized information is arranged to suit the needs and requirements of the decision maker. Accessible information is available when the decision maker needs it. Useful information has meaning to the person who receives it. Cost-effective information should give more value than it costs to produce.

3. What Is Meant by Character, Field, Record, and File?

Data is classified in a hierarchy, with each level of data consisting of one or more items from the lower level. A bit is the smallest unit of data a computer can process. Eight bits grouped together in a unit form a byte, and each byte represents a single character, which can be a number, letter, space, punctuation mark, or other symbol. A field is a combination of one or more related characters or bytes and is the smallest unit of data a user accesses. A record is a group of related fields. A data file is a collection of related records stored on a storage medium such as a hard disk or optical disc.

4. What Are File Maintenance Techniques and Validation Techniques?

File maintenance refers to the procedures that keep data current. File maintenance procedures include adding records when new data is obtained, modifying records to correct inaccurate data or to update old data with new data, and deleting records when they no longer are needed. Validation is the process of comparing data with a set of rules or values to find out if the data is correct. Many programs perform a validity check that analyzes data, either as you enter it or after you enter it, to help ensure that it is correct. Types of validity checks include an alphabetic check, a numeric check, a range check, a consistency check, a completeness check, and a check digit.

5. How Is a File Processing Approach Different from the Database Approach?

In a file processing system, each department or area within an organization has its own set of data fi les. The records in one fi le may not relate to the records in any other fi le. Two major weaknesses of fi le processing systems are redundant data (duplicated data) and isolated data. With a database approach, many programs and users share the data in a database. The database approach reduces data redundancy, improves data integrity, shares data, permits easier access, and reduces development time. A database, however, can be more complex than a fi le processing system, requiring special training and more computer memory, storage, and processing power than fi le processing systems. Data in a database also can be more vulnerable than data in fi le processing systems.

6. What Functions Are Common to Most Database Management Systems?

Database management systems (DBMSs) are available for many sizes and types of computers. Whether designed for a small or large computer, most DBMSs perform common functions. A data dictionary, sometimes called a repository, contains data about each fi le in the database and each field in those fi les. A DBMS offers several methods to retrieve and maintain data in the database, such as query languages, query by example, forms, and report generators. A query language consists of simple, English-like statements that allow users to specify the data to display, print, or store. Query by example (QBE) has a graphical user interface that assists users with retrieving data. A form, sometimes called a data entry form, is a window on the screen that provides areas for entering or modifying data in a database. A report generator, also called a report writer, allows users to design a report on the screen, retrieve data into the report design, and then display or print the report. To supply security, most DBMSs can identify different levels of access privileges that define the actions a specific user or group of users can perform for each field in a database. If a database is damaged or destroyed, a DBMS provides techniques to return the database to a usable form. A backup is a copy of the database. A log is a listing of activities that modify the contents of the database. A recovery utility uses the logs and/or backups to restore the database using rollforward or rollback techniques. In a rollforward, also called forward recovery, the DBMS uses the log to reenter changes made to the database since the last save or backup. In a rollback, also called backward recovery, the DBMS uses the log to undo any changes made to the database during a certain period. Continuous backup is a backup plan in which all data is backed up whenever a change is made.

7. What Are Characteristics of Relational, Object-Oriented, and Multidimensional Databases?

A data model consists of rules and standards that define how the database organizes data. Three popular data models are relational, object-oriented, and multidimensional. A relational database stores data in tables that consist of rows and columns. A relational database developer refers to a fi le as a relation, a record as a tuple, and a field as an attribute. A relational database user refers to a fi le as a table, a record as a row, and a field as a column. A relationship is a link within the data in a relational database. Structured Query Language (SQL) allows users to manage, update, and retrieve data in a relational database. An object-oriented database (OODB) stores data in objects. An object is an item that contains data, as well as the actions that read or process the data. Applications appropriate for an object-oriented database include a multimedia database, a groupware database, a computer-aided design (CAD) database, a hypertext database, and a hypermedia database. Object-oriented databases often use an object query language (OQL) to manipulate and retrieve data. A multidimensional database stores data in dimensions. These multiple dimensions, sometimes known as a hypercube, allow users to access and analyze any view of the database data. No standard query language exists for multidimensional databases. One application that uses multi-dimensional databases is a data warehouse, which is a huge database that stores and manages the data required to analyze historical and current transactions. A smaller version of a data warehouse is the data mart, which contains a database that helps a specific group or department make decisions.

8. How Are Web Databases Accessed?

To access data in a Web database, you fill in a form or enter search text on a Web page, which is the front end to the database. A Web database usually resides on a database server, which is a computer that stores and provides access to a database. One type of program that manages the sending and receiving of data between the front end and the database server is a CGI (Common Gateway Interface) script.

9. What Are the Responsibilities of Database Analysts and Administrators?

A database analyst (DA), or data modeler, focuses on the meaning and usage of data. The DA decides on the placement of fields, defines data relationships, and identifies users’ access privileges. A database administrator (DBA) requires a more technical inside view of the data. The DBA creates and maintains the data dictionary, manages database security, monitors database performance, and checks backup and recovery procedures. In small companies, one person often is both the DA and DBA. In larger companies, the responsibilities of the DA and DBA are split among two or more people.

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Assignment Discovering Computer 2011 - Chapter 9 Communications & Networks

Assignment from Mr. Tri Djoko Wahjono, Ir., M.Sc.

Name : Tommy Hendrawan

NIM / Class : 1701309513 / 01PCT

Assignment : Discovering Computer 2011 - Chapter 9 Communications & Networks

1. What Is the Purpose of the Components Required for Successful Communications, and What Are Various Sending and Receiving Devices?

Computer communications describes a process in which two or more computers or devices transfer data, instructions, and information. Successful communications requires a sending device that initiates a transmission instruction, a communications device that connects the sending device to a communications channel, a communications channel on which the data travels, a communications device that connects the communications channel to a receiving device, and a receiving device that accepts the transmission of data, instructions, or information. All types of computers and mobile devices serve as sending and receiving devices in a communications system.

2. How Are Computer Communications Used?

Communications technologies include blogs, chat rooms, e-mail, fax, FTP, instant messaging, newsgroups, RSS, video conferencing, VoIP, Web, Web folders, and wikis. Users can send and receive wireless messages to and from smart phones, cell phones, handheld game consoles, and other mobile devices using text messaging, picture messaging and video messaging, and wireless instant messaging. People connect wirelessly to the Internet through a wireless Internet access point. A hot spot is a wireless network that provides Internet connections to mobile computers and devices. A cybercafé is a coffeehouse, restaurant, or other location that provides computers with Internet access. A global positioning system (GPS) analyzes signals sent by satellites to determine an earth-based receiver’s geographic location. Many software products provide a means to collaborate, or work online with other users connected to a server. Groupware is software that helps groups of people work on projects or share information over a network. Voice mail allows someone to leave a voice message for one or more people. Web services describe standardized software that enables programmers to create applications that communicate with other remote computers.

3. What Are the Advantages of Using a Network, and How Are LANs, MANs, and WANs Different?

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A network is a collection of computers and devices connected together via communications devices and transmission media. Advantages of using a network include facilitating communications, sharing hardware, sharing data and information, sharing software, and transferring funds. Networks typically are classified as a local area network (LAN), which connects computers in devices in a limited geographical area; a metropolitan area network (MAN), which is a high-speed network that connects local area networks in a larger area, such as city or town; or a wide area network (WAN), which covers a large geographic area using a communications channel that combines many types of media.

4. How Are a Client/Server and Peer-to-Peer Networks Different, and How Does a P2P Network Work?

On a client/server network, one or more computers acts as a server, sometimes called a host computer, which controls access to network resources and provides a centralized storage area, while the other computers and devices on the network are clients that rely on the server for resources. A peer-to-peer network is a simple network that typically connects fewer than 10 computers that have equal responsibilities and capabilities. P2P is an Internet peer-to-peer network on which users access each other’s hard disks directly and exchange fi les over the Internet.

5. How Are a Star Network, Bus Network, and Ring Network Different?

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A network topology refers to the layout of computers and devices in a communications network. Three commonly used network topologies are the star, bus, and ring. On a star network, all computers and devices on the network connect to a central device, thus forming a star. A bus network consists of a single central cable to which all computers and other devices connect. On a ring network, a cable forms a closed loop (ring) with all computers and devices arranged along the ring.

6. What Are Various Network Communications Standards?

A network standard defines guidelines that specify the way computers access a medium, the type(s) of medium, the speeds on different types of networks, and the type of physical cable or wireless technology used. Network communications standards include the following. Ethernet specifies that no central computer or device on the network should control when data can be transmitted. Token ring requires devices to share or pass a special signal, called a token. TCP/IP divides data into packets. Wi-Fi identifies any network based on the 802.11 standards for wireless communications. Bluetooth uses short-range radio waves to transmit data. UWB specifies how two UWB devices use short-range radio waves to communicate at high speeds. IrDA transmits data wirelessly via infrared light waves. RFID uses radio signals for communications. WiMAX is a network standard developed by IEEE that specifies how wireless devices communicate over the air in a wide area. The Wireless Application Protocol (WAP) specifies how some mobile devices can display Internet content.

7. What Is the Purpose of Communications Software?

Communications software helps users establish a connection to another computer or network; manages the transmission of data, instructions, and information; and provides an interface for users to communicate with one another.

8. What Are Various Types of Lines for Communications over the Telephone Network?

The telephone network uses dial-up lines or dedicated lines. A dial-up line is a temporary connection that uses one or more analog telephone lines for communications. A dedicated line is an always-on connection established between two communications devices. Dedicated lines include the following. ISDN is a set of standards for digital transmission of data over standard copper telephone lines. DSL transmits at fast speeds on existing standard copper telephone wiring. FTTP, or Fiber to the Premises, uses fiber-optic cable to provide extremely high-speed Internet access to a user’s physical permanent location. Two specific types of FTTP are FTTH (Fiber to the Home) and FTTB (Fiber to the Building). A T-carrier line is a long-distance digital telephone line that carries multiple signals over a single communications line. ATM is a service that carries voice, data, video, and multimedia at extremely high speeds.

9. What Are Commonly Used Communications Devices?

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A communications device is hardware capable of transmitting data between a sending device and a receiving device. A dial-up modem converts digital signals to analog signals and analog signals to digital signals so that data can travel along analog telephone lines. A digital modem sends and receives data and information to and from a digital line. An ISDN modem transmits digital data to and from an ISDN line, while a DSL modem transmits digital data to and from a DSL line. A cable modem, sometimes called a broadband modem, is a digital modem that sends and receives digital data over the cable television network. A wireless modem uses the cell phone network to connect to the Internet wirelessly from mobile computers and devices. A network card enables a computer or device that does not have built-in networking capability to access a network. A wireless access point allows computers and devices to transfer data wirelessly. A router connects multiple computers or other routers together and transmits data to its correct destination on the network. A hub or switch is a device that provides a central point for cables in a network.

10. How Can a Home Network Be Set Up?

A home network connects multiple computers and devices in a home. An Ethernet network connects each computer to a hub with a physical cable. A home powerline cable network uses the same lines that bring electricity into the house. A phoneline network uses existing telephone lines in a home. Most home networks use a Wi-Fi network.

11. What Are Various Physical and Wireless Transmission Media?

Transmission media consist of materials or substances capable of carrying one or more signals. Physical transmission media use tangible materials to send communications signals. Twisted-pair cable consists of one or more twisted-pair wires bundled together. Coaxial cable consists of a single copper wire surrounded by at least three layers: an insulating material, a woven or braided metal, and a plastic outer coating. Fiber-optic cable consists of thin strands of glass or plastic that use light to transmit signals. Wireless transmission media send communications signals through the air or space. Infrared (IR) sends signals using infrared light waves. Broadcast radio distributes radio signals through the air over long and short distances. Cellular radio is a form of broadcast radio that is used widely for mobile communications. Microwaves are radio waves that provide a high speed signal transmission. A communications satellite is a space station that receives microwave signals from an earth-based station, amplifies the signals, and broadcasts the signals back over a wide area.

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Assignment Discovering Computer 2011 - Chapter 8 Operating Systems & Utility Programs

Assignment from Mr. Tri Djoko Wahjono, Ir., M.Sc.

Name : Tommy Hendrawan

NIM / Class : 1701309513 / 01PCT

Assignment : Discovering Computer 2011 - Chapter 8 Operating Systems & Utility Programs

1. What Is System Software, and What Are the Two Types of System Software?

System software consists of the programs that control or maintain the operations of a computer and its devices. Two types of system software are operating systems and utility programs. An operating system (OS) is a set of programs containing instructions that work together to coordinate all the activities among computer hardware resources. A utility program, also called a utility, performs maintenance-type tasks, usually related to managing a computer, its devices, or its programs.

2. What Are the Functions of an Operating System?

The operating system starts and shuts down a computer, provides a user interface, manages programs, manages memory, coordinates tasks, configures devices, establishes an Internet connection, monitors performance, provides utilities, updates automatically, controls a network, and administers security. The user interface controls how data and instructions are entered and how information is displayed on the screen. Two types of user interfaces are a graphical user interface (GUI) and a command-line interface. Managing programs refers to how many users, and how many programs, an operating system can support at one time. An operating system can be single user/single tasking, single user/multitasking, multiuser, or multiprocessing. Memory management optimizes the use of random access memory (RAM). If memory is insufficient, the operating system may use virtual memory, which allocates a portion of a storage medium to function as additional RAM. Coordinating tasks determines the order in which tasks are processed. Tasks include receiving data from an input device, processing instructions, sending information to an output device, and transferring items between storage and memory. Configuring devices involves loading each device’s driver when a user boots the computer. A driver, short for device driver, is a small program that tells the operating system how to communicate with a specific device. Establishing an Internet connection sets up a connection between a computer and an Internet access provider. A performance monitor is an operating system program that assesses and reports information about computer resources and devices. Operating systems often provide the capability of managing and searching for fi les, viewing images, securing a computer from unauthorized access, uninstalling programs, and other tasks. Most operating systems also include an automatic update feature that provides updates to the program. A server operating system is an operating system that organizes and coordinates how multiple user’s access and share network resources. Network administrators typically have an administrator account that enables them to access fi les, install programs, and specify network settings, including creating user accounts and establishing permissions.

3. What Is the Startup Process on a Personal Computer?

Booting is the process of starting or restarting a computer. When a user turns on a computer, the power supply sends a signal to the system unit. The processor chip finds the ROM chip(s) that contains the BIOS (basic input/output system), which is firmware with the computer’s startup instructions. The BIOS performs the power-on self-test (POST) to check system components and compares the results with data in a CMOS chip. If the POST completes successfully, the BIOS searches for the system files and the kernel of the operating system, which manages memory and devices, and loads them into memory from storage. Finally, the operating system loads configuration information, requests any necessary user information, and displays the desktop on the screen. The operating system executes programs in the Startup folder, which contains a list of programs that open automatically when you boot the computer.

4. What Are Features of Windows 7, Mac OS X, UNIX, and Linux Operating Systems?

A stand-alone operating system is a complete operating system that works on a desktop computer, notebook computer, or mobile computing device. Windows 7 is Microsoft’s fastest, most efficient operating system to date, offering quicker program start up, built-in diagnostics, automatic recovery, improved security, enhanced searching and organizing capabilities, and an easy-to-use interface. Most users choose from Windows 7 Starter, Windows 7 Home Premium, Windows 7 Ultimate, or Windows 7 Professional editions. Mac OS X is a multitasking operating system available only for Apple computers. UNIX is a multitasking operating system developed at Bell Laboratories. Linux is a popular, multitasking UNIX-type operating system that is open source software, which means its code is available to the public for use, modification, and redistribution.

5. What Are Various Server Operating Systems?

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Server operating systems include Windows Server 2008, UNIX, Linux, Solaris, and NetWare. Windows Server 2008 is an upgrade to Windows Server 2003 and includes features of previous Windows Server versions. UNIX, like Linux, is a multipurpose operating system because it is both a stand-alone and server operating system. Solaris, a version of UNIX developed by Sun Microsystems, is a server operating system designed specifically for e-commerce applications. Novell’s NetWare is a server operating system designed for client/server networks.

6. What Are the Features of Several Embedded Operating Systems?

Mobile devices and many consumer electronics have an embedded operating system that resides on a ROM chip. Popular embedded operating systems include Windows Embedded CE, Windows Mobile, Palm OS, iPhone OS, BlackBerry, Google Android, embedded Linux, and Symbian OS. Windows Embedded CE is a scaled-down Windows operating system designed for use on communications, entertainment, and computing devices with limited functionality. Windows Mobile, an operating system based on Windows Embedded CE, provides a user interface designed for specific types of smart phones and PDAs. Palm OS is an operating system used on smart phones and PDAs. iPhone OS, developed by Apple, is an operating system for the iPhone and iPod touch. The BlackBerry operating system runs on handheld devices supplied by RIM. Google Android is an operating system developed by Google for mobile devices. Embedded Linux is a scaled-down Linux operating system for smart phones, PDAs, portable media players, and other devices requiring an embedded operating system. Symbian OS is an open source multitasking operating system designed for smart phones.

7. What Is the Purpose of Several Utility Programs?

Most operating systems include several built-in utility programs. A file manager performs functions related to fi le management. A search utility attempts to locate a fi le on your computer based on criteria you specify. An image viewer displays, copies, and prints the contents of a graphics fi le, such as photos. An uninstaller removes a program and any associated entries in the system fi les. A disk cleanup utility searches for and removes unnecessary fi les. A disk defragmenter reorganizes the fi les and unused space on a computer’s hard disk. A backup utility is used to copy, or back up, selected fi les or an entire hard disk to another storage medium. A restore utility reverses the backup process and returns backed up fi les to their original form. A screen saver displays a moving image or blank screen if no keyboard or mouse activity occurs for a specified time. A personal firewall detects and protects a personal computer from unauthorized intrusions. An antivirus program protects computers against a virus, or potentially damaging computer program, by identifying and removing any computer viruses. A spyware remover detects and deletes spyware and other similar programs. An adware remover detects and deletes adware. Internet filter programs can include Web filtering software, an anti-spam program, a phishing filter, and a pop-up blocker. A file compression utility shrinks the size of a fi le so that it takes up less storage space. A media player allows you to view images and animation, listen to audio, and watch video fi les on a computer. Disc burning software writes text, graphics, audio, and video fi les on a recordable or rewritable CD, DVD, or Blu-ray Disc. A personal computer maintenance utility identifies and fixes operating system problems and improves a computer’s performance.

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Assignment Discovering Computer 2011 - Chapter 7 Storage

Assignment from Mr. Tri Djoko Wahjono, Ir., M.Sc.

Name : Tommy Hendrawan

NIM / Class : 1701309513 / 01PCT

Assignment : Discovering Computer 2011 - Chapter 7 Storage

1. How Are Storage Devices Different from Storage Media?

A storage medium is the physical material on which a computer keeps data, instructions, and information. The number of bytes (characters) a storage medium can hold is its capacity. A storage device is the computer hardware that records and/or retrieves items to and from storage media. Writing is the process of transferring items from memory to a storage medium, and reading is the process of transferring these items from a storage medium into memory.

2. What Are the Characteristics of an Internal Hard Disk?

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A hard disk, also called a hard disk drive or hard drive, is a storage device that contains one or more inflexible, circular platters that use magnetic particles to store data, instructions, and information. Traditionally, hard disks stored data using longitudinal recording, which aligned the magnetic particles horizontally. With perpendicular recording, hard disks align the particles vertically, making much greater storage capacities possible. The capacity of a hard disk is determined from whether it uses longitudinal or perpendicular recording, the number of platters it contains, and the composition of the magnetic coating on the platters. A platter is made of aluminum, glass, or ceramic and is coated with a material that allows items to be recorded magnetically on its surface. Each platter has two read/write heads, one for each side. The location of a read/write head often is referred to by its cylinder, which is the vertical section of a track that passes through all platters. Formatting is the process of dividing the disk into tracks and sectors. A track is a narrow recording band that forms a full circle on the surface of the disk. The disk’s storage locations are divided into pie-shaped sections, which break the tracks into small arcs called sectors. While the computer is running, the platters in the hard disk rotate at 5,400 to 15,000 revolutions per minute (rpm), which allows nearly instant access to all tracks and sectors on the platters. Transfer rate is the speed with which data, instructions, and information transfer to and from a storage device. Access time measures the amount of time it takes a storage device to locate an item on a storage medium, or the time required to deliver an item from memory to the processor.

3. What Is the Purpose of Network Attached Storage Devices, External and Removable Hard Disks, and Hard Disk Controllers?

A network attached storage (NAS) device is a server connected to a network with the sole purpose of providing storage. NAS devices often use a RAID configuration. An external hard disk is a separate freestanding hard disk that connects with a cable to a USB or FireWire port on the system unit or communicates wirelessly. External hard disks have storage capacities up to 4 TB and more. A removable hard disk can be inserted or removed from a built-in or external drive. Removable hard disks have storage capacities up to 1 TB. A disk controller consists of a special-purpose chip and electronic circuits that control the transfer of data, instructions, and information from a disk to and from the system bus and other components in a computer. A hard disk controller may be part of the hard disk on the motherboard, or it may be a separate adapter card inside the system unit.

4. What Are the Various Types of Flash Memory Storage?

Flash memory chips are a type of solid state media, which means they consist entirely of electronic components and contain no moving parts. A solid state drive (SSD) typically uses flash memory to store data, instructions, and information. A memory card is a removable flash memory device that you insert and remove from a slot in a computer, mobile device, or card reader/writer. Common memory cards include CompactFlash (CF), Secure Digital (SD), Secure Digital High Capacity (SDHC), microSD, microSDHC, xD Picture Card, Memory Stick, and Memory Stick Micro (M2). A USB flash drive, sometimes called a thumb drive, is a flash memory storage device that plugs in a port on a computer or mobiledevice. An ExpressCard module is a removable device that fits in an ExpressCard slot. ExpressCard modules can add memory, storage, communications, or other capabilities to a computer.

5. What Is Cloud Storage, and What Are Its Advantages?

Cloud storage is an Internet service that provides storage for computer users. Available for all sizes of users, with various degrees of storage services available for home and business users, cloud storage fees vary, depending on the user’s storage requirements. Advantages include accessing fi les on the Internet from any computer or device with Internet access; storing large audio, video, and graphics fi les on the Internet instantaneously; allowing others to access their fi les on the Internet; viewing time-critical data and images immediately; storing off-site backups of data; and providing data center functions.

6. What Are the Characteristics of Optical Discs?

An optical disc is a type of storage media that consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser. Optical discs, which primarily store software, data, digital photos, movies, and music, contain microscopic pits (indentations) and lands (flat areas) in their middle layer. Optical discs commonly store items in a single track that spirals from the center of the disc to its edge. Like a hard disk, the single track is divided into evenly sized sectors.

7. How Are the Various Types of Optical Discs Different?

A CD-ROM, or compact disc read-only memory, is a type of optical disc that uses laser technology to store items. Users can read the contents of standard CD-ROMs but cannot erase or modify their contents. A CD-R (compact disc-recordable) is a multisession disc on which users can record their own items, such as text, graphics, and audio. Each part of a CD-R can be written on only one time, and the disc’s contents cannot be erased. A CD-RW (compact disc-rewritable) is an erasable disc that can be written on multiple times. An archive disc stores photos from an online photo center in the jpg fi le format. A Picture CD is a single-session CD-ROM that stores digital versions of fi lm using the jpg format at a lower resolution than an archive disc. A DVD-ROM (digital versatile disc-read-only memory or digital video disc-read-only memory) is a high capacity optical disc that you can read but not write on or erase. A newer, more expensive DVD format is Blu-ray Disc-ROM (BD-ROM), with higher capacity and better quality than standard DVDs. Many types of recordable and rewritable DVD formats are available. DVD-R and DVD+R are DVD-recordable formats. BD-R is a high-capacity DVD-recordable format. DVD-RW, DVD+RW, and DVD+RAM are rewritable DVD formats that allow users to erase and record multiple times. BD-RE is a high-capacity rewritable DVD format.

8. How Are Tape, Magnetic Stripe Cards, Smart Cards, Microfilm and Microfiche, and Enterprise Storage

Used?

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Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information at a low cost. A tape drive reads and writes data and information on tape. Business users utilize tape most often for long-term storage and backup. A magnetic stripe card is a credit card, entertainment card, bank card, or other similar card with a stripe that contains information identifying you and the card. A magnetic stripe card reader reads the information stored on the stripe. A smart card, which is similar in size to a credit or ATM card, stores data on a thin microprocessor embedded in the card. A smart card reader reads the information on the smart card and updates it if necessary. Microfilm is a 100- to 215-foot roll of film. Microfiche is a small sheet of film, usually about 4 x 6 inches. Microfilm and microfiche reduce the amount of paper firms must handle, are inexpensive, and have the longest life of any storage media. Enterprises use computers, servers, and networks to manage and store huge volumes of data and information. In an enterprise, some storage systems can provide more than 185 TB of storage, and optical disc servers hold hundreds of optical discs.

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Assignment Discovering Computer 2011 - Chapter 6 Output

Assignment from Mr. Tri Djoko Wahjono, Ir., M.Sc.

Name : Tommy Hendrawan

NIM / Class : 1701309513 / 01PCT

Assignment : Discovering Computer 2011 - Chapter 6 Output

1. What Are the Four Types of Output?

Output is data that has been processed into a useful form. Computers process data (input) into information (output). Four categories of output are text, graphics, audio, and video. An output device is any hardware component that conveys information to one or more people. Commonly used output devices include display devices; printers; speakers, headphones, and earbuds; data projectors; interactive whiteboards; and force-feedback game controllers and tactile output.

2. What Are the Characteristics of Various Display Devices?

A display device, or simply display, is an output device that visually conveys text, graphics, and video information and consists of a screen and the components that produce the information on the screen. Desktop computers typically use a monitor as their display device; most mobile computers and devices integrate the display into the same physical case. LCD monitors, LCD screens, and plasma monitors are types of flat-panel displays. A flatpanel display is a lightweight display device with a shallow depth that typically uses LCD or gas plasma technology. An LCD monitor is a desktop monitor that uses a liquid crystal display to produce images. A plasma monitor is a display device that uses gas plasma technology, which substitutes a layer of gas for the liquid crystal material in an LCD monitor. A CRT monitor is a desktop monitor that contains a cathode-ray tube (CRT). CRT monitors take up more desk space and thus are not used much today.

3. What Factors Affect the Quality of an LCD monitor or LCD screen? 

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The quality of an LCD monitor or LCD screen depends primarily on its resolution, response time, brightness, dot pitch, and contrast ratio. Resolution is the number of horizontal and vertical pixels in a display device; a higher resolution uses a greater number of pixels and provides a sharper image. Response time is the time in milliseconds that it takes to turn a pixel on or off. Brightness of an LCD monitor or LCD screen is measured in nits; the higher the nits, the brighter the image. A nit is a unit of visible light intensity equal to one candela per square meter. Dot pitch, or pixel pitch, is the distance in millimeters between pixels on a display device. Contrast ratio describes the difference in light intensity between the brightest white and darkest black that can be displayed on a monitor.

4. What Are the Various Ways to Print?

Users can print by connecting a computer to a printer with a cable that plugs in a port on the computer. Bluetooth printing uses radio waves to transmit output to a printer. With infrared printing, a computer or other device communicates with the printer via infrared light waves. Some digital cameras connect directly to a printer via a cable; others store images on memory cards that can be removed and inserted in the printer. Networked computers can communicate with the network printer via cables or wirelessly.

5. How Is a Nonimpact Printer Different from an Impact Printer?

A printer is an output device that produces text and graphics on a physical medium, such as paper. A nonimpact printer forms characters and graphics on a piece of paper without actually striking the paper. Some spray ink, while others use heat or pressure to create images. Commonly used nonimpact printers are ink-jet printers, photo printers, laser printers, thermal printers, mobile printers, label and postage printers, plotters, and large-format printers. An impact printer forms characters and graphics on a piece of paper by striking a mechanism against an inked ribbon that physically contacts the paper. These printers commonly produce near letter quality (NLQ) output, which is print quality slightly less clear than what is acceptable for business letters. Two commonly used types of impact printers are a dot-matrix printer and a line printer.

6. What Are Ink-Jet Printers, Photo Printers, Laser Printers, Multifunction Peripherals, Thermal Printers, Mobile Printers, Label and Postage Printers, and Plotters and Large-Format Printers?

An ink-jet printer is a type of nonimpact printer that forms characters and graphics by spraying tiny drops of liquid ink onto a piece of paper. One factor that influences the quality of an ink-jet printer is its resolution. Printer resolution is measured by the number of dots per inch (dpi) a printer can print.

A photo printer is a color printer that produces photo-lab-quality pictures. A laser printer is a high-speed, high-quality nonimpact printer that operates in a manner similar to a copy machine, creating images using a laser beam and powdered ink, called toner. Laser printers usually print at faster speeds than inkjet printers. A multifunction peripheral (MFP), or all-in-one device, is a single device that looks like a printer or a copy machine but provides the functionality of a printer, scanner, copy machine, and perhaps a fax machine. Some MFPs use color ink-jet printer technology; others include a black-and-white or color laser printer. The primary disadvantage of these devices is that if the device breaks down, you lose all four functions. A thermal printer generates images by pushing electrically heated pins against heat-sensitive paper. They are inexpensive, but the print quality is low and the images tend to fade over time. A mobile printer is a small, lightweight, battery-powered printer that allows a mobile user to print from a notebook computer or other mobile device. A label printer is a small printer that prints on an adhesive-type material that can be placed on a variety of items. Most label printers also print bar codes. A postage printer is a special type of label printer that has a built-in scale and prints postage stamps. Plotters are sophisticated printers used to produce high-quality drawings, such as blueprints, maps, and circuit diagrams. A large-format printer uses ink-jet technology on a large scale to create photo-realistic quality color prints.

7. What Are the Uses and Characteristics of Speakers, Headphones, and Earbuds?

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Speakers, headphones, and earbuds are three commonly used audio output devices. An audio output device is a component of a computer that produces music, speech, or other sounds. Many personal computer users add stereo speakers to their computers, including game consoles and mobile devices, to generate higher-quality sounds. With headphones or earbuds, only the individual wearing the headphones or earbuds hears the sound from the computer. The difference is that headphones cover or are placed outside of the ear, whereas earbuds, or earphones, rest inside the ear canal. A headset is a device that functions as both headphones and a microphone, so that user’s hands are free for typing or other activities while listening to audio output.

8. What Are the Purposes and Features of Data Projectors, Interactive Whiteboards, and Force-Feedback Game Controllers and Mobile Devices?

A data projector is a device that takes the text and images displaying on a computer screen and projects them onto a larger screen so that an audience of people can see the image clearly. An LCD projector attaches directly to a computer and uses its own light source to display information shown on the computer screen. A digital light processing (DLP) projector uses tiny mirrors to reflect light. An interactive whiteboard is a touch-sensitive device, resembling a dry-erase board, which displays the image on a connected computer screen. Joysticks, wheels, gamepads, and motion- sensing game controllers are input devices used to control actions of a player or object in computer games, simulations, and video games. Today’s joysticks, wheels, gamepads, and motion- sensing game controllers also include force feedback, which is a technology that sends resistance to the device in response to actions of the user. Some input devices include tactile output that provides the user with a physical response from the device.

9. What Output Options Are Available for Physically Challenged Users?

Hearing-impaired users can instruct programs to display words instead of sound. The Magnifier in Windows enlarges text and other items in a window on the screen. Visually impaired users can enlarge items on the screen and change other settings, such as increasing the size or changing the color of text to make words easier to read. Blind users can work with voice output instead of a monitor via Windows Narrator. Another alternative is a Braille printer, which prints information in Braille on paper.

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Assignment Discovering Computer 2011 - Chapter 5 Input

Assignment from Mr. Tri Djoko Wahjono, Ir., M.Sc.

Name : Tommy Hendrawan

NIM / Class : 1701309513 / 01PCT

Assignment : Discovering Computer 2011 - Chapter 5 Input

1. What Is Input, and What Are the Differences among a Program, a Command, and a User Response?

Input is any data or instructions entered into the memory of a computer. A program is a series of related instructions that tells a computer what tasks to perform and how to perform them. A command is an instruction that causes a program to perform a specific action. A user issues a user response by replying to a question displayed by a program to perform certain actions.

2. What Keys Are Commonly Found on Desktop Computer Keyboards, and How Do Keyboards for Mobile Computers and Devices Differ from Desktop Computer Keyboards?

A keyboard is an input device that contains keys users press to enter data and instructions into a computer. Computer keyboards have a typing area that includes letters of the alphabet, numbers, punctuation marks, and other basic keys. Most keyboards also have function keys programmed to issue commands; toggle keys that switch between two states when pressed; and keys used to move the insertion point, or cursor, on the screen. A gaming keyboard is a keyboard designed specifically for users who enjoy playing games on the computer. On notebook computers and some other mobile devices, the keyboard is built into the top of the system unit. To fi t in these mobile computers and devices, the keyboards usually are smaller and have fewer keys than desktop computer keyboards.

3. What Are Different Mouse Types, and How Do You Use a Mouse?

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A mouse is a pointing device that fits under the palm of your hand. An optical mouse uses devices that emit and sense light to detect the mouse’s movement. A laser mouse uses a laser and is more expensive than an optical mouse. An air mouse allows you to control objects, media players, and slide shows by moving the mouse in predetermined directions through the air. A wireless mouse, or cordless mouse, transmits data using wireless technology. As you move a mouse, the mouse pointer moves on the screen. You then press a mouse button (usually the left) to click objects. Some programs support mouse gestures, where users can perform certain actions by holding a mouse button while moving the mouse in a particular pattern.

4. What Are the Various Types of Touch Screens, and How Does a Touch-Sensitive Pad Work?

A touch screen is a touch-sensitive display device. Touch screens that recognize multiple points of contact at the same time are known as multi-touch. Users interact with touch screens by touching areas of the screen such as pictures, numbers, letters, or locations identified on the screen. A kiosk is a freestanding computer that usually includes a touch screen. Microsoft Surface is a 30-inch tabletop display that allows one or more people to interact with the screen using their fingers or hands. A touch-sensitive pad is an input device that enables users to scroll through and play music, view pictures, watch videos or movies, adjust volume, and/or customize settings on a portable media player or other mobile device.

5. What Are the Various Types of Pen Input, and What Are Other Types of Input for Smart Phones?

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With pen input, you touch a stylus or digital pen on a flat surface, such as a screen on a monitor or mobile device, a signature capture pad, or a graphics tablet, to write, draw, or make selections. A stylus is a small metal or plastic device that looks like a tiny ink pen but uses pressure instead of ink. A digital pen, which is slightly larger than a stylus, features electronic erasers and programmable buttons. Handwriting recognition software is a program that translates handwritten letters and symbols into characters a computer or mobile device can process. A signature capture pad captures signatures written with a stylus or pen attached to a device. Some smart phones have digital cameras that have touch-sensitive pads. Others have a portable keyboard or optical keyboard built in.

6. What Are the Purposes of Gamepads, Joysticks and Wheels, Light Guns, Dance Pads, and Motion-Sensing Game Controllers?

A gamepad controls the movement and actions of players or objects in video games or computer games. A joystick is a handheld vertical lever that you move to control a simulated vehicle or player. A wheel is a steering-wheel-type device that you turn to simulate driving a vehicle. A light gun is used to shoot targets as you pull the trigger on the weapon. A dance pad is an electronic device, divided into panels, which users press with their feet. Motion sensing game controllers, such as the Wii Remote, guide on-screen elements by moving a handheld input device in predetermined directions through the air.

7. How Does Resolution Affect the Quality of a Picture Captured on a Digital Camera? 

A digital camera allows users to take pictures and store the photographed images digitally. Resolution is the number of horizontal and vertical pixels in a display device. The greater the number of pixels the camera uses to capture a picture, the better the quality of the picture. Thus, the higher the resolution, the better the picture quality, but the more expensive the camera.

8. How Are Voice Recognition, Web Cams, and Video Conferencing Used?

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Voice recognition, also called speech recognition, is the computer’s capability of distinguishing spoken words. A Web cam, also called a PC video camera, is a digital video camera that enables users to capture video and still images and then send or broadcast the images over the Internet. A video conference is a meeting between two or more geographically separated people who use a network or the Internet to transmit audio and video data.

9. How Do the Various Types of Scanners and Reading Devices Work?

A scanner, or optical scanner, is a light-sensing input device that reads printed text and graphics and translates the results into a form the computer can process. A flatbed scanner works in a manner similar to a copy machine except it creates a fi le of the document. An optical reader uses a light source to read characters, marks, and codes and converts them into digital data that a computer can process. Optical character recognition (OCR) reads characters from ordinary documents. Optical mark recognition (OMR) reads hand-drawn marks such as small circles or rectangles. A bar code reader, or barcode scanner, is an optical reader that uses laser beams to read a bar code, or identification code. RFID (radio frequency identification) uses radio signals to communicate with an embedded tag placed in or attached to an object, an animal, or a person. A magnetic stripe card reader, also called a magstripe reader, reads the magnetic stripe on the back of credit cards and other similar cards. MICR (magnetic-ink character recognition) reads text printed with magnetized ink.

10. What Are Various Biometric Devices?

A biometric device translates a personal characteristic into digital code that is compared with a digital code stored in the computer to identify an individual. A fingerprint reader captures curves and indentations of a fingerprint. A face recognition system captures a live face image and compares it with a stored image. A hand geometry system measures the shape and size of a hand. A voice verification system compares live speech with a stored voice pattern. A signature verification system recognizes the shape of a signature. An iris recognition system reads patterns in the iris of the eye. Retinal scanners scan patterns of blood vessels in the back of the retina.

11. How Do POS Terminals, Automated Teller Machines, and DVD Kiosks Work?

A terminal is a computer, usually with limited processing power, that enables users to send data to and/or receive information from a host computer. POS terminals, ATMs, and DVD kiosks are special-purpose terminals. A POS (point-of-sale) terminal records purchases, processes credit or debit cards, and updates inventory. An automated teller machine (ATM) is a self-service banking machine that connects to a host computer through a network. A DVD kiosk is a self-service DVD rental machine that connects to a host computer through a network.

12. What Are Alternative Input Devices for Physically Challenged Users?

Voice recognition is ideal for visually impaired users. A keyguard is a plate placed over the keyboard that allows users with limited hand mobility to rest their hands and press only one key at a time. Keyboards with larger keys or an on-screen keyboard displayed on a user’s screen also are available. A small trackball or a head-mounted pointer helps users with limited hand movement to control the pointer or insertion point. Two developments in the prototype stage are gesture recognition and computerized implant devices.

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Assignment Discovering Computer 2011 - Chapter 4 The Components of The System Unit

Assignment from Mr. Tri Djoko Wahjono, Ir., M.Sc.

Name : Tommy Hendrawan

NIM / Class : 1701309513 / 01PCT

Assignment : Discovering Computer 2011 - Chapter 4 The Components of The System Unit

1. How Are Various Styles of System Units on Desktop Computers, Notebook Computers, and Mobile Devices Different? 
The system unit is a case that contains electronic components of the computer used to process data. On desktop personal computers, most storage devices also are part of the system unit. On most notebook computers, including netbooks, the keyboard and pointing device often occupy the area on top of the system unit, and the display attaches to the system unit by hinges. The location of the system unit on a Tablet PC varies, depending on the design of the Tablet PC. On mobile computers and devices, the display often is built into the system unit.
With game consoles, the input and output devices, such as controllers and a television, reside outside the system unit. On handheld game consoles, portable media players, and digital cameras by contrast, the packaging around the system unit houses the input devices and display.

2. What Are Chips, Adapter Cards, and Other Components of the Motherboard? 
The motherboard, sometimes called a system board, is the main circuit board of the system unit. The motherboard contains many electronic components including a processor chip, memory chips, expansion slots, and adapter cards. A computer chip is a small piece of semiconducting material, usually silicon, on which integrated circuits are etched. Expansion slots hold adapter cards that provide connections and functions not built into the motherboard.

3. What Are the Control Unit and Arithmetic Logic Unit Components of a Processor, and What Are the Four Steps in a Machine Cycle? 
The processor, also called the central processing unit (CPU), interprets and carries out the basic instructions that operate a computer. Processors contain a control unit that directs and coordinates most of the operations in the computer and an arithmetic logic unit (ALU) that performs arithmetic, comparison, and other operations. The machine cycle is a set of four basic operations — fetching, decoding, executing, and storing — that the processor repeats for every instruction.

4. What Are the Characteristics of Various Personal Computer Processors, and How Are Processors
Cooled? 
A multi-core processor is a single chip with two or more separate processor cores. Two common multi-core processors are dual-core and quad-core. A dual-core processor is a chip that contains two separate processor cores. A quad-core processor is a chip with four or more separate processor cores. Intel produces the Core processor family for high- performance personal computers, the Pentium and Celeron processor families for basic personal computers, and the Xeon and Itanium processor families for workstations and low-end servers.
AMD manufactures Intel-compatible processors, which have an internal design similar to Intel processors. Some devices have a system-on-a-chip processor that integrates the functions of a processor, memory, and a video card on a single chip. Heat sinks/pipes and liquid cooling technologies are used to dissipate processor heat. A heat sink is a small ceramic or metal component that absorbs and disperses heat. A smaller device called a heat pipe cools processors in notebook computers, including netbooks and Tablet PCs. Some computers use liquid cooling technology, which uses a continuous flow of fluid(s) to transfer heated fluid away from the processor.

5. What Is a Bit, and How Does a Series of Bits Represent Data? 
Most computers are digital and recognize only two discrete states: off and on. To represent these states, computers use the binary system, which is a number system that has just two unique digits — 0 (for off) and 1 (for on) — called bits. A bit (short for binary digit), is the smallest unit of data a computer can process. Grouped together as a unit, 8 bits form a byte, which provides enough different combinations of 0s and 1s to represent 256 individual characters. The combinations are defined by patterns, called coding schemes, such as ASCII and Unicode.

6. How Do Program Instructions Transfer in and out of Memory? 
When a program starts, the program’s instructions and data are transferred to memory from storage devices. The program and operating system instructions are in memory, and the program’s window appears on the screen. When you quit the program, the program instructions are removed from memory, and the program no longer is displayed on the screen. 7. What Are the Various Types of Memory? Memory usually consists of one or more chips on the motherboard or some other circuit board in the computer. The system unit contains volatile and nonvolatile memory. Volatile memory loses its contents when the computer’s power is turned off. Nonvolatile memory does not lose its contents when the computer’s power is turned off. RAM is the most common type of volatile memory. ROM, flash memory, and CMOS are examples of nonvolatile memory. RAM (random access memory), also called main memory, consists of memory chips that can be read from and written to by the processor and other devices. ROM (read-only memory) refers to memory chips storing permanent data and instructions that usually cannot be modified. Flash memory can be erased electronically and rewritten. CMOS (complementary metal-oxide semiconductor) technology uses battery power to retain information even when the power to the computer is turned off.

8. What Are the Purpose and Types of Expansion Slots and Adapter Cards, and What Are the Different Slots for Flash Memory Devices? 
An expansion slot is a socket on the motherboard that can hold an adapter card. An adapter card, sometimes called an expansion card, is a circuit board that enhances functions of a component of the system unit and/or provides a connection to a peripheral. A sound card enhances the sound-generating capabilities of a personal computer. A video card, also called a graphics card, converts computer output into a video signal that displays an image on the screen. A memory card is a removable fl ash memory device that you insert and remove from a slot in a personal computer, a game console, a mobile device, or card reader/writer. A USB flash drive plugs in a USB port on a computer or mobile device. A PC Card slot or an Express Card slot holds a PC Card or Express Card module.

9. What Is the Difference between a Port and a Connector, and What Are the Differences among the Various Types of Ports? 
A port is the point at which a peripheral attaches to or communicates a system unit so that it can send data to or receive information from the computer. A connector joins a cable to a port. A USB port, short for universal serial bus port, can connect up to 127 different peripherals together with a single connector. A FireWire port can connect multiple types of devices that require faster data transmission speeds. Bluetooth technology uses radio waves to transfer data between two devices. A SCSI port attaches the system unit to SCSI peripherals, such as disk drives and printers. An eSATA port connects an external SATA hard disk to a computer. An IrDA port allows wireless devices to transmit signals to a computer via infrared light waves. A serial port transmits data one bit at a time. A MIDI port connects the system unit to a musical instrument.

10. What Are the Types of Buses in a Computer? 
A bus is an electrical channel along which bits transfer within the circuitry of a computer, allowing devices both inside and attached to the system unit to communicate. The data bus transfers actual data, and the address bus transfers information about where the data should reside in memory. The size of a bus, called the bus width, determines the number of bits that the computer can transmit at one time. The larger the bus width, the faster the computer transfers data. A computer has a system bus, or front side bus (FSB); possibly a backside bus (BSB); and an expansion bus.

11. What Is the Purpose of a Power Supply, and How Does It Keep Cool? 
A power supply is the component of the system unit that converts wall outlet AC power into DC power for the computer to use. A fan built directly into the power supply keeps it cool. Some have variable speed fans, and many newer computers have additional fans near components in the system unit. Notebook computers, including netbooks and Tablet PCs, can be placed on a cooling pad to help disperse heat.

12. How Do You Clean a System Unit on a Personal Computer or Mobile Device? 
Before cleaning the exterior of a computer or mobile device, turn it off, and if necessary, unplug it from the electrical outlet, remove the battery, and disconnect all cables from the ports. Use compressed air to blow away dirt from any openings on the case, such as drives, slots, ports, and fan vents. Use an anti-static wipe to clean the exterior of the case and a cleaning solution on a soft cloth to clean the screen. While working inside the case, be sure to wear an anti-static wristband. If you do not feel comfortable cleaning the inside of the case, you can have a professional or Computer Company clean it for you. Use a vacuum and compressed air to remove dust inside the case.

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