General Application Concepts & Uses | CompTIA IT Fundamentals FC0-U61 | 3.6

In this video you will learn about single-platform software, cross-platform software, licensing, & software installation best practices.

Single-Platform Software

Single-platform software is software that meets the requirements of a particular operating system. For example, Microsoft Windows is currently designed to run on Intel-compatible 32- or 64-bit processors. CorelDraw is a single-platform graphics application that runs on Microsoft Windows but does not run on macOS or Linux.

Cross-Platform Software

Cross-platform software is computer software that is implemented on multiple computing platforms. Cross-platform software may be divided into two types; one requires individual building or compilation for each platform that it supports, and the other can be directly run on any platform without special preparation. For example, Adobe Creative Cloud & Microsoft Office 365 are cross-platform software that can run on macOS and Microsoft Windows. Microsoft Office 365 can also run on iOS and Android mobile platforms.

Compatibility Concerns

When dealing with cross-platform applications, some compatibility issues may present themselves when you’re moving files between platforms, such as:

  • Font substitutions could take place if the same fonts are not available on the originating device and the targeted device.  Font substitutions could significantly change the appearance of documents, presentations, and graphic designs.
  • Differences in photo-handling support between Windows and macOS or between Windows and iOS or Android could cause problems when viewing or using images.
  • Differences in built-in video and music playback support between Windows and macOS or between Windows and iOS or Android could cause problems when playing videos or music.
  • Differences in feature support across platforms can cause problems in opening files or in viewing file contents.  Microsoft Office apps such as PowerPoint and Excel include compatibility checkers that can help find issues with older versions’ support for new features.

If considering a cross-platform app, some vendors offer comparison documents you can consult to see if there are differences in how the app works on different platforms.  There can also be issues when running apps made for older versions of Windows on newer versions.


A software license is a legal instrument (usually by way of contract law, with or without printed material) governing the use of redistribution of software.  Under United States copyright law, all software is copyright protected, in both source code and object code forms, unless that software was developed by the United States government, in which case it cannot be copyrighted.  Software piracy, the use of software that has not been licensed, has been a major problem for the industry since the first personal computers were introduced in the late 1970s. The use of unlicensed software can lead to heavy fines for companies that are caught using it, and unlicensed software obtained through illegal download sites can carry malware as an unwanted bonus.

The following sections discuss various types of software licenses. Licenses are often referred to as end-user license agreements, or EULAs.

Single Use

A single-use license is the authorization that grants one user the right to use a software package.  It may grant the user the right to install the software on only one machine, or it may authorize installation on any number of machines as long as the same license is the only user.  Some single-use licenses permit software to be installed into a virtual machine, but others permit installation onto physical hardware only.

Side Note:  A virtual machine (VM) exists in software but looks and acts like a physical computer to the operating system and apps installed in it.  A single physical computer can have several VMs running on it. Virtualization is the process of creating a VM and installing an operating system and apps in it.

Group Use/Site License

A group use or site license grants the usage rights to the software to a set number of users. Rather than having to assign the rights to a specific number of users, a group license enables people with certain group policy rights to access it. In practice this means a group license can make the software available to a group of users who meet the requirements, with the flexibility to allow additional users to access the software as they are granted more rights within the group policy.

Concurrent License

A concurrent license is a software license that is based on the number of simultaneous users accessing the program.  It typically deals with software running in the server where users connect via the network. For example, Adobe Creative Cloud apps have a two-user concurrent license:  they can be installed on two computers managed or owned by the same user. The user can run the apps on either computer as needed, but not at the same time. If the user needs to run the apps on a third computer, the apps on the other computers are deactivated by the Creative Cloud app manager.  Don’t confuse concurrent licensing with that of simultaneous licensing. For example, Microsoft Office 365 Home allows up to five users to install and use the product at the same time on macOS or Windows computers. Up to five tablets and five smartphones can also use the subscription.

Open Source vs. Proprietary

Most commercial apps are proprietary.  Proprietary software is any software that is copyrighted and bears limits against use, distribution and modification that are imposed by its publisher, vendor or developer. Proprietary software remains the property of its owner/creator and is used by end-users/organizations under predefined conditions. Windows, macOS, and iOS are considered proprietary operating systems. You have to pay for licensing.

Open source software is software with source code that anyone can inspect, modify, and enhance. Open source operating systems such as Linux and Android and apps such as Apache Open Office, Libre Office, and the GIMP are examples of open source software.  Open source apps are typically made available free of charge. Commercial versions of open source apps charge for support and for enhancements.

Subscription vs. One-Time Purchase

There are two ways to produce a software license:

  • One-time purchase:  This is a single payment to license the software for as long as the user wants to use it.  A one-time purchase license does not expire.
  • Subscription:  This is a monthly or yearly payment to license the software for that time period.  A subscription expires if the user stops paying for it. The software might run in a reduced-capability mode or stop working completely until the subscription is renewed.

Depending on the specific licensing agreement, a one-time purchase may not be transferable to a different computer.  On the other hand, a subscription is usually transferable. A subscription also enables users to receive frequent updates (sometimes monthly) to apps and is usually less expensive than making a one-time purchase every year.  A subscription for multiple users can be much less expensive. A one-time purchase makes sense for a single user who does not need the additional programs and services, will not be replacing the app for at least three years, and does not need frequent updates.  Many established software vendors are moving to the subscription model.

Product Keys and Serial Numbers

For one-time software purchases, product keys and serial numbers are used to authenticate the software license.  The software key or serial number must be entered before the software can be used. In some cases, the serial number must be sent to the vendor after the product is ordered to receive a product key that is entered to activate the software. With some subscription software the user’s account information is used to activate the software.  With a multiuser subscription the subscribing user sends invitations to other users granting them permission to install and activate the software.

Sample Product Key

Software Installation Best Practices

The following sections discuss best practices and common errors to avoid when installing software.

Reading Instructions

RTFM: Read The Friendly Manual. You should always read the instructions before installing software in order to avoid problems like the following with your installation:

  • System is not compatible with the app.  Check the system requirements (operating system version, processor type and speed, RAM size) for the app and compare it to your device’s operating system and hardware. For Windows, open the System properties sheet or select Settings, System, About.  For macOS, open About this Mac.  For Linux with a GUI, open a dialog such as Settings.  For Linux from the command line (Terminal), run inxi.
  • Missed last-minute changes to the app or the installation process.  To avoid this problem, check the installation media for a “readme” file.  It could be a text file or a file you can open with most word processing programs, such as an RTF (Rich Text) or DOC (Microsoft Word) file.  Read it before you start the installation process.
  • Lost license key or serial number means no installation.  Be sure to keep the packaging if it contains a license key or serial number.  Without this information, you have an overpriced CD or DVD that can’t be used.  If you are installing a downloaded app, check your email and save your purchase receipt and installation information.
  • Clean up the old before installing the new.  If you are upgrading an older version of an app, there may be special instructions before proceeding.  You might need to remove (uninstall) the older version first or save the preference files (personalized settings) for reuse.
  • Back up the old (operating system) before installing the new.  The regular backup app in Windows 10 backs up data files, not the operating system, and the image backup utilities in older versions of Windows don’t always work well.  Use a third-party image backup utility (an image is the entire contents of the system drive).
  • Close other apps to avoid problems later.  Frequently, you are advised to close other running apps before starting the installation process.  If you don’t, you might have problems updating shared program file libraries.
  • No reboot, problems follow.  If the installation program prompts you to reboot after installation, do it.  Your new software (or hardware) might not work until you do. However, if you are installing more than one program, you can reboot after installing the other apps.
  • Have an ISO file but no optical drive?  Many apps are distributed as ISO (optical disc image) files (.iso is the usual extension for these files).  You can sometimes install directly from an ISO file by mounting the media. However, in some cases, you need to create an optical disc or USB install media.
  • Unzip now, install later.  Many apps for Windows and some for other operating systems are downloaded as PKZIP (ZIP) files.  To unzip these files in Windows, you can use the Extract All options in File Manager.  The default location for the extracted files is a folder with the same name as the ZIP file, but you can choose a different location if desired.  To extract files in macOS, double-click the file. To extract files in Linux, you can use the GUI file manager or run the Terminal command unzip filename.

Reading Agreements

An end-user license agreement (EULA) is a license that gives a user the right to use a software application in some manner. EULAs are designed to enforce specific software use limitations, such as only using the software on one computer. By entering into the agreement, the user is given permission to use and benefit from the software. Sadly, the license agreement (EULA) is one of the least-read documents in all of IT.  However, it’s worth reading to discover what your rights and responsibilities are. Due to some licenses being dry reading, some vendors will not permit you to click to accept the agreement until you scroll through the entire window.  Open source licenses are typically much less restrictive than proprietary software licenses, but they exist for the same reason: to tell you what you can and cannot do with software.

Advanced Options

If you don’t change any of the usual settings for a program, you are performing a standard installation.  When you select different options than usual, the installation is called a custom installation.  Some typical options include the following:

  • Where to install the software
  • Install for all users of the computer, or only the current user
  • Install all available import/export filters for documents, photos, and other files
  • Install all software features
  • Allow software to open all supported file types (file associations)
  • Check for automatic updates

If you have difficulties starting your system after installing a new operating system, either as a fresh installation or as an upgrade, there are custom startup options you can use to help recover.  The term Safe Mode is used for many of these options. In Safe Mode, only essential hardware and software are available, and the display might run at a lower resolution than normal. With Windows 7, you can press the F8 key (Fn+F8 on some keyboards) to bring up a menu with startup options such as Safe Mode (loads minimal drivers), Safe Mode with Network Support (minimal drivers with access to your network/internet), and others.  In Windows 10, the startup options are similar but are accessed from either the Settings menu (Advanced Startup) or from the Sign-in screen. To start your Mac in Safe Mode, hold down the left Shift key when you turn it on. Some Linux distros use the same option as Mac. For others, you change options in the boot manager. Look up the details for the distro you use.