Universal OS

Universal OS, developed by Fall Inc, is a proprietary operating system that is designed to run seamlessly on various devices such as desktop computers, smartphones, tablet computers, smartwatches, smart TVs, IoT devices, and automobiles. The entire operating system is composed of a hybrid kernel and various layers called Packages, and they are designed for specific devices. Each device variant will have different packages installed. For example, a smartphone will have the phone package installed. As a result, Fall can develop operating systems for different devices without changing many codes.

Universal OS was announced at the Fall International Developer Festival on May 20, 2013, with its first developer preview released just a day after. The first public version of Universal OS was released on October 14, 2014. The latest major release of the operating system, Universal OS 4.0, was released to the public on December 17, 2020. Currently, all of Fall's consumer electronic products run Universal OS.

Development of PTOS
In the early 2000s, Fall began working on an autonomous operating system targeting government customers in case of technology blockade in the future. The operating system is built on top of a unix-like PT kernel that is primarily derived from FreeBSD's code, similar to Apple's Mac OS X. On March 25, 2003, the first version of PTOS was released. For the next few years, there were little updates to PTOS while Fall was focusing on building Windows computers.

PTOS to Universal OS
After Fall became an OEM partner of Microsoft, the company was consistently losing its revenue. In 2012, therefore, Fall revisited its original PTOS, and started a project that was codenamed Irvine. The purpose of Project Irvine was to make PTOS available to regular consumers. Initially, the engineering team within Fall was working on a new iteration of the PT kernel that was codenamed Fairmont. In January 2013, Project Irvine received its official name, Universal OS, and the PT kernel was renamed Universal Core. On May 20, 2013, Fall held its first developer conference, Fall International Developer Festival. At the conference, Fall unveiled Universal OS to the public for the first time, and planned an early 2014 public release. Later that month, the government of Plant Kingdom subsidised Fall Inc. m$100 million to encourage the further development of the operating system. In June 2013, Fall began its work on the user experience part of the OS. Additionally, Fall also sat the goal of making Universal OS "the most compatible operating system on the planet." As a part of the goal, Fall added support for Linux and Mac apps to the OS in the summer.

On September 10, 2013, Fall released the second developer preview for Universal OS. This version included a redesigned user interface that looked more clean and modern, as well as features such as virtual desktop, multi-display support, multitasking, support for Mac and Linux applications, window resizing, desktop personalization, and more. Additionally, it was the first version of Universal OS that supported mobile phones.

On October 22, 2013, Fall released the third developer preview of the operating system. This release introduced a built-in terminal application, taskbar application preview, a redesigned settings application, and a graphical system crash screen.

On December 9, 2013, Fall released the fourth developer preview of Universal OS, which added spilt-screen, an application hub (similar to macOS's Launchpad and Windows's Start), and file context menus. Later that month, Fall announced that support for Windows application will be available in the spring of 2014 via Wine. As a result, the public release of the operating system was pushed back to late 2014.