Softwares and Its types

1. OPERATING SYSTEMS (System Software)

• Is software that acts as an interface between the user, application software, and the computer hardware

EXAMPLE OF OPERATING SYSTEM

1. Microsoft Disk operating system ( Ms. DOS)
2. Windows ( 98, 2000, XP, Vista)
3. Linux
4. Unix

PARTS OF OPERATING SYSTEM

1. Shell – it is the outer part of an operating system and it is responsible for interacting with the operating system
2. Kernel – Responsible for managing and controlling computer resources such as the processor, main memory, storage devices, input devices, output devices, and communication devices

RESOURCE UNER THE OPERATING SYSTEM CONTROL

• The processor
• Main memory
• Input/Output Device
• Secondary storage devices
• Communication devices and ports

FUNCTIONS OF OPERATING SYSTEM

1. Job scheduling

– it is the process of the operating system to keep a list of jobs currently being run by the computer and clocking them in and out of the processor.

1. Interrupt handling

• It is a break from the normal sequential processing of instructions in a program

1. Resource control and allocation

• It is a situation where the processor gives computer resources a unique number called interrupt number so that it can be able to recognize and prioritize it.

1. Memory Management

• It is where the operating system constantly assigns main memory storage partitions to data an instructions

1. Error handling

• It is a situation whereby an operating system alerts the user of errors that arises in case of illegal operations, hardware, or software failure.

1. Input/output handling

NOTE

What is an interrupt request?

• Is a unique number that is given to a resource for identification purposes

What is the importance of interrupt computer

• To enable urgent tasks/ processes to b given the first priority during program execution

What is virtual memory

• Part of the hard disk that acts as maim memory
• The operating system organizes the main memory in blocks called page frames. The processes are divided into partitions that can fit on a page. The operating system swaps these pages between the main memory and the hard disk. The part of the hard disk where these pages are held in the virtual memory.

What is a deadlock

• Is where a particular task holds resources and refuses to release it for other tasks to use.

CLASSIFICATION OF OPERATING SYSTEM

They are classified into three ways/types:-

1. According to the number of tasks handled concurrently
2. Single task – one task is operated at a any given time
3. Multi-Task – More than one task is processed apparently simultaneously

1. According to the number of users
2. Single user – Single (One) user operates a computer at any given time
3. Multi-user – More than one user can operate the computer at the same time

1. Human-computer interface / G U I

• Interaction between the computer and the user.

1. Command-line – The user types the commands at the command prompt to activate them by pressing the enter key

Advantages

• Fast in operation by experienced users
• flexible
• Use Less memory
• Don’t require expensive hardware

Disadvantages

- Hard to learn and understand

- Not user friendly

- If you mistype or forgot the syntax of writing the command, you cannot operate it

- Difficult to learn

- Difficult to move information from one application to another

- Difficult to design and produce printed reports

- Do not support multi-users and multi-task

1. Menu-driven – The user is provided with a list of menu to choose from

Advantages

• More user friendly than the command line
• Easier to learn and understand
• Eliminates the problem of forgetting the syntax of command since commands are provided for you

Disadvantages

• Slow to operate
• Not flexible

1. Graphical User Interface(GUI) – The user interacts with the computer using icons and menus and selects them using a pointer

Advantages

- It is easy to learn and operate

- They make it easy to exchange information between application

- Reduce the user training time and cost due to their inform mode of operation

- It is more user friendly

- Supports multi-user and multi-task

Disadvantages

• The cost of GUI supporting hardware is higher
• Many objects on the GUI confuse new computer users
• - Require faster processors that are more expensive

WINDOW as used in the operating system

Is a rectangular object created on a screen by an operating system to contain input or output data for a particular program

PROPERTIES OF A WINDOW

• Title bar
• Display/ working area
• Horizontal and vertical scrolls bars
• Menu bars
• Status bar
• Toolbar

TYPES OF MENUS

1. Pop up menu
2. Pop down menu
3. Submenu( Cascading/ Sidekick menu)

COMPUTER FILES

Are classifies into types:-

1. System Files

Are files that contain information that is critical to the operations of the computer

1. Application Files

Are files that hold programs or application files

2.Utility Software

Utility software helps to manage, maintain, and control computer resources. Operating systems typically contain the necessary tools for this, but separate utility programs can provide improved functionality. Utility software is often somewhat technical and targeted at users with a solid knowledge of computers. If you use a computer mostly for e-mail, some Internet browsing, and typing up a report, you may not have much need for these utilities. However, if you are an avid computer user, these utilities can help make sure your computer stays in tip-top shape.

Examples of utility programs are antivirus software, backup software, and disk tools. Let's look at each of these in a bit more detail.

Antivirus software, as the name suggests, helps to protect a computer system from viruses and other harmful programs. A computer virus is a computer program that can cause damage to a computer's software, hardware, or data. It is referred to as a virus because it has the capability to replicate itself and hide inside other computer files.

One of the most common ways to get a virus is to download a file from the Internet. Antivirus software scans your online activity to make sure you are not downloading infected files. New viruses are coming out all the time, so antivirus software needs to be updated very frequently.

Backup software helps in the creation of a backup of the files on your computer. Most computer systems use a hard disk drive for storage. While these are generally very robust, they can fail or crash, resulting in costly data loss. Backup software helps you copy the most important files to another storage device, such as an external hard disk. You can also make an exact copy of your hard disk.

Increasingly, backup software uses cloud storage to create backups. This typically means you pay a fee to use the storage space of a third party and use their backup software to manage which files are going to be backed up.

Disk tools include a range of different tools to manage hard disk drives and other storage devices. This includes utilities to scan the hard disks for any potential problems, disk cleaners to remove any unnecessary files, and disk defragmenters to re-organize file fragments on a hard disk drive to increase performance. Disk tools are important because the failure of a hard disk drive can have disastrous consequences. Keeping disks running efficiently is an important part of overall computer maintenance.

3. Packaged Software:

Packaged software that is often called a software package is a commercial program that’s obtainable to the general public and sold to them at explicit costs. Package software is developed by computer technicians. it is the compilation of programs that are grouped together in order to provide the public with different tools in the same group. It can’t be modified or altered even if there is a need. The essential definition says that, once several software packages are grouped during a bundle and supply solutions to people, then it gets the specified name.

The best example of package software is Microsoft Office, which has many tools grouped together for example Office, Access, Excel, Note, and PowerPoint.

4.Custom Software:Custom software is a specific program that is advanced for a goal in a department or in a company. Its cost is higher than package software because custom software is made for a specific purpose. Unlike package software, custom software can be modified or changed if there is a need because this software is custom-built.

The best example of custom software is that a company that wishes to own a management system for its employees and keeping track of their working hours. whenever one task is performed during a specific condition, as an example, folks obtaining the task of planning a calculator through C++ language, then it’ll become a custom product.

5. Application Software:

 Applications software is capable of dealing with user inputs and helps the user to complete the task. It is also called end-user programs or only an app. It resides above system software. The first user deal with system software after that he/she deals with application software. The end-user uses applications software for a specific purpose. It programmed for simple as well as complex tasks. It either be installed or access online. It can be a single program or a group of small programs that referred to as an application suite. Some examples of Application Software are Word processing software, Spreadsheets Software, Presentation, Graphics, CAD/CAM, Sending an email, etc.