Introduction to IT C182: Unit 45 Computer Software

Three of the most common operating systems are

*Windows *Mac *Linux.

Windows File Structure

1)a backward slash (\) is used to express directory paths; 2)Windows is not case sensitive when searching for files, which means capitalization is irrelevant; 3)Windows root directory is referred to by letter, commonly C drive; and 4)the user's home directory is found within C:\Users.

In a Linux shell

1)a forward slash (/) is used to express directory paths; Linux is case-sensitive; 2) the root directory in Linux is expressed as a single forward slash; and 3)most flavors of Linux place the home directory within the /home/.

Compilers

A compiler translates source code into machine language. A compiler checks source code for errors before translating it into object code. If the source code is found to have errors, the compiler specifies the errors. Errors must be resolved (also known as debugged) before the compiler can successfully recompile the source code. C, C++, C#, and Java programs need compilers to execute.

Application Software

Application software consists of the programs that perform tasks specific to the machine's general purpose. A computer used to maintain a store's inventory needs different software than a machine used by a mechanical engineer. Spreadsheet, database, desktop publishing, accounting, and program development software are all examples of application software. Those who are not in the IT field might refer to application software as productivity or collaboration software or tools.

Contemporary operating systems have graphical user interfaces (GUIs).

Contemporary operating systems have graphical user interfaces that allow end users to issue commands through input devices such as mouses, keyboards, or touch screens. On a touch screen, a user can directly manipulate icons with their finger or a stylus.

File Management

File managers are able to bundle files into directories or folders. Directories can be placed within other directories, resulting in a hierarchical file structure. The directory path tells a user where the file is located within the file system. Directory paths are often written as the folder names separated by slashes.

Interpreters

Interpreters translate and execute source code one line at a time. If the interpreter finds an error, the process is terminated at the statement containing the error and displays an error message. The error must be resolved before the interpreter will continue to the next line. Interpreters convert instructions one statement at a time when the program is run. Perl and Python execute using interpreters.

Local and Cloud Applications

Local applications are application software stored on individual computers. Local applications are mostly found on personal machines, as they are often impractical for large organizations. Cloud computing delivers services, including computing, storage, databases, networks, software, analytics, and intelligence, thus offloading infrastructure resource requirements to the cloud service provider. Cloud applications, or cloud apps, are software units where cloud-based and local components work together to perform tasks.

Software Licensing

Microsoft and Apple require you to purchase a license to install their operating systems, whether it is for personal or business use. Further, it is closed-source, meaning they do not permit anyone to modify their operating system code. The operating system is developed by Microsoft and Apple. Linux, on the other hand, is open-source and collaborators work together from around the world. Open-source systems allow individuals and organizations to open and modify the operating system's kernel, the heart of the operating system.

Application and System Software

Software can be divided into application and system software. System software is general-purpose software that is used to operate computer hardware. It provides a platform to run application software. Application software is specific-purpose software used to perform a specific task

Software Packing

Software can be packaged in various ways, including shareware, freeware, and public domain. Shareware is an application that can be installed as a trial limited by time and/or functionality. If the user decides to purchase the application or subscription, they then get the full functionality. Freeware is, as the term suggests, free. However, freeware and shareware are both protected by end-user license agreements (EULA) and copyright laws (where applicable). This is where freeware and shareware are differentiated from software in the public domain. Public domain software has no EULA and no intellectual property protections and is available for anyone to download and use at their own discretion. However, in the United States, a copyright gives an author of a software package the ability to prevent unauthorized duplication for at least 35 years. Other countries may have similar copyright laws. Take a moment now to research what those laws might be for your country.

Productivity Software

Software that people use to complete daily tasks is called productivity software. Productivity software is used to complete tasks such as writing documents, managing personal information, giving presentations, storing data, and sending email.

Common High-Level Programming Languages

Some common high-level programming languages are outlined below, with characteristics that make them unique or suitable for particular tasks.

System Software

System software performs tasks that are common to computer systems in general. The system software provides the infrastructure needed to run application software, allowing it to interface with the hardware of the computer system. System software can be divided into utility software and operating systems. Operating systems contain the user interface and the kernel of the operating system.

Kernel

The kernel is the internal part of an operating system. The kernel contains the operating system components that perform the basic functions required by the computer installation. One such unit is the file manager whose function is to coordinate the machine's storage. The file manager maintains records of all the files stored in secondary storage, including where each file is stored, which users have access, and which portions of the storage are available for new files.

Device Drivers

The kernel of an operating system stores a collection of device drivers, software that communicates with controllers or other peripheral devices. Device drivers translate generic requests into the technical steps required to complete the task. Device drivers, sometimes referred to as middleware, facilitate the communication of hardware and software. A print driver needs to be installed if a user wants to send a document to the printer. A Bluetooth headphone driver is necessary if a user wants to listen to music on Bluetooth headphones. Some device drivers are installed automatically, while others would need to be downloaded and installed from the manufacturers' sites.

User Interface

The user interface allows end users to communicate with the operating system. is an important part of a machine's functionality, it is only the intermediary between the end user and the operating system. The distinction between the user interface and the internal parts of the operating system is emphasized by the fact that some operating systems require the user to select an available interface according to their preferences.

Command-line interfaces (CLIs)

are a type of user interface that communicate with end users through textual messages using a keyboard and monitor.

Utility Software

extends the capabilities of an operating system. helps customize the operating system's function. For example, installation utility software consists of programs for performing activities that are fundamental to computer installation but not included in the operating system. Some examples of utility software include software to compress or decompress data, play multimedia presentations, and handle network communications.

Operating Systems Users

is also tasked with protecting the computer's resources from unauthorized users. When a computer is used by multiple people, each user is assigned their own account on the computer. A user account is a record within the operating system with information such as a name, password, and user privileges (e.g., administrator vs. standard user). The operating system uses this information during each log-in to control access to the system and resources.

Memory Management

is another component of an operating system's kernel. The memory manager manages the system's primary main memory. When a computer is performing a single task, managing the memory is minimal. When a computer is performing many tasks simultaneously, the duties of the memory manager are extensive. The memory manager needs to find and assign the main memory space for each of the processes and restrict the actions of each process to the memory space allocated to that program. When more main memory space is needed, the memory manager can create an illusion of additional space by rotating programs and data between the primary and secondary memory, a technique called paging. The additional memory space created in secondary memory by paging is referred to as virtual memory.

Mac.

is developed by Apple. Previous versions of Mac operating systems include Snow Leopard, Lion, Mountain Lion, Safari, and Sierra. Like Microsoft, Apple's operating systems are closed-source. Mac operating systems are known for their media editing and graphic rendering capabilities.

Windows.

is developed by Microsoft. Previous versions of Windows desktop operating systems include Windows XP, Windows 95, Windows 98, Windows Vista, and currently Windows 10. At the time of this writing, Windows is closed-source with a subscription model. Windows intends to keep the operating system name as Windows 10, but continue adding versions to each update. Windows desktop operating systems are common for personal computers (PCs). Typically, Microsoft products are known for their easy-to-use design.

Linux

is open-source operating system software. There are many different versions of Linux, referred to as flavors, including Linux Mint, Mandrake, Fedora, Ubuntu, Debian, and CentOS. These operating systems are free for anyone to use. However, there are vendors (e.g., Red Hat, Cisco) that offer Linux-based operating systems, adding cost for support and/or hardware.

Algorithms

sounds complicated and somewhat intimidating, but an is simply a step-by-step formula outlining how to execute a task. If you have ever baked a cake, pie, or cookies, or followed a recipe to make a special entrée for family or friends, you have experienced a real-world example. provides a specifically structured set of inputs (i.e., the steps of a recipe) required to produce a specific output (i.e., your cake, pie, cookies, or special entrée).

Operating systems

typically fall into one of two categories: network operating system or desktop operating system. Many types of operating systems are available, each with different file structures and features.

are examples if system software

• Microsoft Windows • Linux • Mac OS X • DOS

are examples if application software

• Spreadsheet • Web browser • Accounting