In 1984, Quantum Software Systems renamed QUNIX to QNX in an effort to avoid any trademark infringement challenges.

Over the years QNX was used mostly for larger projects, as its 44k kernel was too large to fit inside the one-chip computers of the era.

In the late-1980s, Quantum realized that the market was rapidly moving towards the Portable Operating System Interface (POSIX) model and decided to rewrite the kernel to be much more compatible at a low level.

This patented[2] concept was developed into the embeddable graphical user interface (GUI) named the QNX Photon microGUI.

To demonstrate the OS's capability and relatively small size, in the late 1990s QNX released a demo image that included the POSIX-compliant QNX 4 OS, a full graphical user interface, graphical text editor, TCP/IP networking, web browser and web server that all fit on a bootable 1.44 MB floppy disk for the 386 PC.

[3][4] Toward the end of the 1990s, the company, then named QNX Software Systems, began work on a new version of QNX, designed from the ground up to be symmetric multiprocessing (SMP) capable, and to support all current POSIX application programming interfaces (APIs) and any new POSIX APIs that could be anticipated while still retaining the microkernel architecture.

Along with the Neutrino kernel, QNX Software Systems became a founding member of the Eclipse (integrated development environment) consortium.

Since the purchase by Harman, QNX software has been designed into over 200 different automobile makes and models, in telematics systems, and in infotainment and navigation units.

[9] On April 9, 2010, Research In Motion (later renamed to BlackBerry Limited) announced they would acquire QNX Software Systems from Harman International Industries.

At the Geneva Motor Show, Apple demonstrated CarPlay which provides an iOS-like user interface to head units in compatible vehicles.

[18] As a microkernel-based OS, QNX is based on the idea of running most of the operating system kernel in the form of a number of small tasks, named Resource Managers.

This is made possible by two key mechanisms: subroutine-call type interprocess communication, and a boot loader which can load an image containing the kernel and any desired set of user programs and shared libraries.

Mishandling of this subtle issue is a primary reason for the disappointing performance of some other microkernel systems such as early versions of Mach.

Later versions of QNX reduce the number of separate processes and integrate the network stack and other function blocks into single applications for performance reasons.

BMP is used to improve cache hitting and to ease the migration of non-SMP safe applications to multi-processor computers.

It can also be configured to run a selected set of critical threads strictly real time, even when the system is overloaded.

[26] QNX Neutrino (2001) has been ported to a number of platforms and now runs on practically any modern central processing unit (CPU) family that is used in the embedded market.

As of June 26, 2023, QNX software is now embedded in over 255 million[27] vehicles worldwide, including most leading OEMs and Tier 1s, such as BMW, Bosch, Continental, Dongfeng Motor, Geely, Ford, Honda, Mercedes-Benz, Subaru, Toyota, Volkswagen, Volvo, and more.

These important relationships have ability to provide the foundational software, middleware, and services behind the world's most critical embedded systems.