Use of computer systems. Data representation in computer systems.

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Plotter.Plotters are special type of printers used to print graphicaloutput on paper. It interprets computer commands and makes line drawings on paper using ulticolored automated pens.

Storage Devices. Storage refers to the media on which data, instructions, and information are kept, as well as the devices that record and retrieve these items. In this section we will discuss about the storage media and storage devices.

Memory versus Storage.It is important to understand the difference between the memory. Memory holds data and instructions temporarily while they are being processed by the CPU. Storage, also called Secondary, Auxiliary storage, or Mass storage, holds items such as data, instruction, and information for future use.

Storage.Storage is non-volatile which means that items in storage remains even when power is removed from the computer. A storage medium is the physical material on which the items are kept. One commonly used storage medium is a disk, which is round, flat piece of plastic or metal with a magnetic coating on which items can be written. A storage device is the mechanism used to record and retrieve items to and from a storage medium.

Storage devices can function as source of input and output. For example, each time a storage device transfers data, instructions, and information from a storage medium into memory (a process called Reading); it functions as an input source. When a storage device transfers these items from memory to a storage medium (a process called Writing), it functions as an output source.

The speed of a storage device is defined by its access time, which is the minimum time it takes the device to locate a single item on the disk. Compared to memory, storage devices are slow. The access time of memory devices are measured in milliseconds.

Hard Disk. Hard Disk drive which is often referred to as Hard Disk or Hard Drive is a device to store and retrieve data in a computer. The hard drive can store important system files like the operating system, program files and other data. Though HDDs were originally designed to be used with computers nowadays the applications for HDDs have expanded beyond computers to include digital video recorders, digital audio players, personal digital assistants, digital cameras and video game consoles. HDD is a non-volatile storage device that stores digitally encoded data. It is an electromagnetically charged surface or set of disks that record data in concentric circles known as tracks. HDDs record data by magnetizing ferromagnetic material directionally, to represent either a 0 or a 1 binary digit. They read the data back by detecting the magnetization of the material. A typical HDD design consists of a spindle which holds one or more flat circular disks called platters, onto which the data is recorded. The platters are made from a non-magnetic material, usually aluminum alloy or glass, and are coated with a thin layer of magnetic material.

Portable Hard Disks. Portable hard disk is an interesting and useful device because you can carry data about all over the place and transfer information, programs, pictures, etc. between computers. Modern portable hard disks have a massive capacity like 500GB.

The System Unit . Тhe System Unit of the computer is the box-like casing which contains the major electronic components that are responsible for the main functions of the computer. It should be mentioned here that many people use to refer to this as the CPU incorrectly. This erroneous reference may be due to CPU: The brain of the commuter being that significant. However, the electronic devices such as CPU, memory, hard disk drive are located inside the System Unit. In addition to the above parts, Motherboard, Floppy Disk Drive, Power Supply unit, and CD-ROM Drive are the other major components that you can find within the system unit. A brief description of each above component is given next.

Motherboard. The motherboard is sometimes called the system board, planner board or main board. It is the main circuit board of a computer. The motherboard contains several connectors for attaching additional boards. Usually, the motherboard contains the CPU, BIOS, memory, mass storage interfaces, serial/parallel ports, expansion slots, and all the controllers required to control standard peripheral devices, such as the display screen, keyboard, and disk drive.All of the basic circuitry and components required for a computer to function are onboard the motherboard or are connected with a cable. The most important component on a motherboard is the chipset. It often consists of two components or chips known as the Northbridge and Southbridge, though they may also be integrated into a single component. These chips determine, to an extent, the features and capabilities of the motherboard.

Power Supply Unit . Power Supply Unit (PSU) is another very important unit found in the system unit. Usually we connect the power code of the computer to the domestic mains supply. Therefore, PSU converts Alternating Current (AC) from mains supply to Direct Current (DC) with the required different voltages needed to power different components of the computer. Power supplies have a certain power output specified in Watts, a standard power supply would typically be able to deliver around 350 Watts. The more components like HDD, CD/DVD drives, and cooling fans, are connected to your computer the greater the power required fro m the power supply

CD-ROM Drive. The CD-ROM drive is a high capacity optical data storage device with a removable disk, it writes data onto or reads data from a storage medium.

A CD-ROM drive may be connected to the computer via an IDE (ATA), SCSI, S-ATA, Firewire, or USB interface or a proprietary interface

Questions:

1. Are ink jet printers better than laser printers?

2. What’s the best way to add devices to a computer system?

3. How can I protect my computer system from theft and damage?

4. List the network connection components.

References

4. Craig VanSlyke. Information Communication Technologies:Concepts. Methodologies, Tools, and Applications.-2008.-4288 p.

5. Brynjolfsson, E., A.Saunders. Wired for Innovation: How Information Technology is Reshaping the Economy. – Cambridge, MA: Mit Press -2010

6. Kretschemer, T. Information Communication Technologies and Productive Growth// A Survey of the Literature, OECD Digital Economy Papers. -2012. –No.195.

Lecture №5. Software.

Purpose:to provide the basic ideas of Software to the Students, to introduce the learner to the Windows operating system and get the learner familiar to operate the computer through the Operating system Windows.

Plan:

1. Software.

2. Types of the software, purpose and characteristic.

Software.

Software is a set of commands that controls the computer operations. Computer software helps us in implementing computing tasks in the computer. Software includes the following functions:

1. Manage the computer recourses of the organization;

2. Provide the user with all recourses necessary to solve computational tasks;

3. Act as mediator between the institutions and the stored information.

One of the key tasks of the managing personal is selection of the appropriate software for the organization needs.

The program is a set of commands that performs a specific task on the computer. The process of creating or writing programs is called programming, and people who specialize in the this kinds of activity are called programmers. The term “program” is synonymous with the data that has to be processed. When the program execution is completed, its unloaded from the computer memory. All modern computers allow you to implement several programs simultaneously.

There are two types of software: system and application. Each type of software performs a variety of functions. System software is a set of programs that manages computer components, such as the processor, communication and peripheral devices. The professionals developing system software are called system programmers. The application software is written for users or by users themselves for performing specific tasks on the computer. The examples of application programmers. Both types of the software are connected and can be presented as shown on the diagram below.

As you can see, all types of the work are closely connected with each other. The system software controls access, to the computer hardware. The application software interacts with the hardware components through the system. End users mostly work with the application software. To provide hardware.

Hardware consists of physical components which make up a computer and is its lowest layers. Surely, there are several layers of hardware: the board contains the chips which, in turn are formed from transistor. However, from the software standpoint, these details are not important.

BIOS or Basic input/output system is the basic layer of software. It deals directly with the signals that control the components. Much of its work is performed when the computers turned on.

Device drivers are supporting programs that the operating system uses to communicate with peripheral devices. To add a new device to the system, you must have the appropriate device drivers. The driver for a hard disk, for example, knows how many tracks there are on the device, and recognizes the command to move the desired track followed by reading or writing data. The advantage of this is that the seller of operating systems does not need to be responsible for the support of each device which is already developed. The device manufacturer supplies the driver operating according to the rules that describe the interaction with the operating system.

The kernel of the operating system is the basis, and performs the most important function. It manages memory, decides which task to perform next, process the different types of possible interruptions. The kernel must always be in the memory, and because of its specific nature, it should work without protective mechanism that protect against erroneous commands or illegal memory accesses. Therefore, it should be as small as possible.

Another part of the operating system is much bigger than a kernel. It performs all the other functions of the operating system. For example, it includes the file system for managing files and folders on the disc. This level is linked with the kernel, when you need to perform basic operations, such as initializing the operation of data transfer to an external device.

Interface application or API(application program interface) is the level where the user programs(applications) are associated with the operating system. For example, suppose that the Web browser application decides that it takes more memory to display a large image file. The operating system is responsible for storing information about the program that use part of the memory at any time. This operating system; the application does not know anything about how the information is organized in the memory, since this is not necessary. The operating system defines an abstraction for memory management, known as API call. All application developers need to know which interface to use to require more RAM. If a new version of the operating system support the use to work so long as the API call is the same.

Library runtime(execution phase of the program library) – a collection of routines that affect the application programs. For example, if you write an application in C to open the file and read the data from it, you will use two standard functions called open and scan. These functions are selected from the library of I/ O routines, called the studio you can use any program in C. They perform the corresponding call the API, any for the operating system to do what you need. The header file studio means that your program does not depend on the set of API calls, so you can run it on any machine that has a C compiler and the c-library. Most programs use subroutines of several libraries during the work. Application layer is routines that perform the actual work, for which the application has been created.

Level of the user interface is responsible for communication between the application and the user. This is usually GUI(graphical user interface), composed of buttons and pop-up menus. Suppose that the user wants user application to open the file.

Script or macros are routines that many applications allow users to create a set of built-in commands. Scripts and macros allow users to automate a sequence of frequently used functions. For example, a Microsoft Excel macro can open the file, copy file from the group a numbers in a spreadsheet perform calculations with them and write the results to another file. If these calculations are required every day, them perhaps it world be useful to collect the calculations in the script, which can be performed by pressing a few keys. Thus, the user may forget the details. Script are placed above the application level commands.

The computer industry today depends on the specialists in each of the above levels. Some people earn by creating BIOS software while others concrete on improving the GUI technology. But a large number of programmers is in the application layer, because people want to use computers for many different tasks.

Role of BIOS.Most part of the course is related to the higher levels of the software hierarchy: file systems, operating system, and application. But in this subchapter we will look at the lowers level of software – BIOS, or basic input/output system. In BIOS, there are three are main functions. It initializes the hardware when the computer stars, loads the operating system and providing basic supports for devices such as a keyboard, a mouse, and serial ports. BIOS is always present, but it is visible only when the computer is turned on, before the operating system takes control.

2.Types of the software, purpose and characteristic.

In the original file system of DOS used in early Windows versions, the names of files were restricted to eight uppercase characters plus the three-character extension separated by a point. Sometimes such style of file designation is named style 8.3. Extension Defines file type. For example, the of purchases saved as a text file can be named SHOPPING.TXT while an abstract created as a Microsoft Word document, perhaps would have the name RESUME.DOC. Below is a list of extensions to the basic types of files

Single-user OS: A type of OS which allows only one user at a time. There can be single-user OS either as single-user single-task or single-user multi-task. The Single-user single-task OS has to deal with only one person at a time running only one application at a time. MS DOS is an example for a single user single task OS.

Multi-user OS: In some situations, we need to share the single computer among few users. So the OS should be a multi-user where more than one user is logged on to the computer and uses it at the same time. These multi users may work with remote desktop connections. Further, these different users may need to run different applications at the same time. So the OS must support multi-task facility as well. Obviously the computer should be a powerful one. Each user draws on a big power of the computer in a shared way. This type of Multi –user multi-task OSs have to manage some tasks as listed below:

Desktop OS vs. Server OS

The OS can also be categorized as Desktop OS and Server OS depending on whether the OS is to be installed in a desktop computer or a server. For example, the latest versions of the Windows OS family can be categorized as follows:

Desktop OS: windows XP, windows 7, Windows 8

Server OS:

Operating Systems for your Desktop PC.

Utility Software. Utility software or utility programs are some small programs which performs specific task, usually related to managing a computer, its devices, or its programs. Most operating systems include several utility programs. Also, you can buy them as stand-alone software that offer improvements over the ones supplied with the OS. Following are some of the specific tasks done by commonly used utility programs:

Viewing files

Compressing files

Diagnosing problems

Scanning disks

Defragmenting disks

Uninstalling software

Backing up files and disks

Checking for viruses

Displaying screen savers

Application Software. Accordingly, the second major class of Software is the Application Software. Application software consists of programs designed to perform specific tasks of users. Application Software, also called a software application or an application, can be used for the following purposes, among others:

As a productivity/business tool

To assist with graphics and multimedia projects

To support household activities, for personal business, or for education

To facilitate communications

Software Package.Based on the purposes as listed above, the application software is three-fold namely General Purpose, Special purpose, and Bespoke. Let us look at each type of applications software briefly.

Special Purpose Application Software.

Special Purpose Application Software is the software created for execution of a single specific task. Some examples are Chess game, calculator, camera application in your mobile phone which allows you only to capture and share pictures, web browsers, media players, calendar programs.

Questions:

1. What is Software?

2. Differentiate System software and Application software.

3. What are program language translators? Briefly describe three translating approaches.

4. State the advantages and disadvantages of Bespoke Application Software.

References

2. Lorenzo Cantoni (University of Lugano, Switzerland) James A. Danowski (University of Illinois at Chicago, IL, USA) Communication and Technology, 576 pages.

3. Craig Van Slyke Information Communication Technologies: Concepts, Methodologies, Tools, and Applications (6 Volumes). ISBN13: 9781599049496, 2008, Pages: 4288

4. Utelbaeva A.K.,Utelbaeva A.K. Study guide for lectures on discipline “Computer science”, Shimkent 2008, 84 pages.

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