New GSSquared release strengthens Apple II emulation on Windows, macOS and Linux

Some emulator updates chase headline features. GSSquared 0.9.0 takes a more practical route. It focuses on the things you notice after using an emulator for more than a few minutes: awkward configuration, inconsistent mouse control, display scaling, audio glitches and the hassle of switching between different virtual machines. That may not sound dramatic. It is useful, though. The new release introduces custom machine profiles, an integrated configuration editor, better GS/OS mouse handling, optional CRT processing and early support for the SecondSight VGA card. It also fixes several problems involving sound, video, resets and storage hardware. The result is a cleaner, more capable Apple II emulator that feels less like a technical experiment and more like an application you can set up once and keep using.

Custom machine profiles remove repeated setup work

The biggest change is the new profile system. GSSquared can emulate several members of the Apple II family, and each machine can have its own combination of processors, expansion cards, drives, video settings and storage devices. That flexibility is useful, but it creates a familiar problem. Every time you switch machines, you may need to rebuild the configuration. Version 0.9.0 lets you save those setups as individual machine profiles.

Each profile uses a .gs2 file based on the TOML configuration format. It can store the selected Apple II model, installed cards, mounted disks and other hardware settings. You might keep one profile for an early Apple II Plus, another for an enhanced Apple IIe and a third for an Apple IIGS running GS/OS. That makes switching systems much quicker. Pick a profile and start.

The emulator lists saved profiles in its system selection screen, but you can also open them directly or drag them into the application. On macOS, the operating system recognises .gs2 files as GSSquared documents, so you can launch a specific machine setup straight from Finder. There’s support for A2Fusion Settings.txt files as well. That should help users bring existing configurations across without rebuilding everything by hand.

The built-in editor keeps configuration manageable

Profiles wouldn’t help much if you had to edit them in a text editor every time something changed. GSSquared 0.9.0 avoids that problem by adding a configuration editor inside the application. You can create a machine, give it a name, choose the platform and assign cards to the available slots. You can also set up storage devices and select disk images that should mount when the system starts.

The editor adjusts itself to the machine you’re building. Available slots and drives reflect the active hardware configuration, which reduces the chance of placing a card where it doesn’t belong or selecting a device the machine can’t use.

It’s a straightforward improvement, but it changes how approachable the emulator feels. You don’t need to remember every configuration command, file path or slot rule. The application handles the structure while still giving experienced users enough control. That balance matters. Emulators often become powerful long before they become comfortable.

GS/OS mouse control feels less awkward

Mouse input can expose an emulator’s rough edges very quickly. In GS/OS, the pointer needs to match the position of the host computer’s cursor. That sounds simple until the emulator adds scaling, borders, letterboxing or a CRT bezel. A small mismatch can make menus and window controls frustrating to use.

GSSquared 0.9.0 improves the way the host pointer maps to the emulated display. The emulator now accounts more accurately for the visible image area, even when the picture doesn’t fill the entire window. It also handles modal windows and the GS/OS Control Panel more consistently. These are small corrections, but you feel them immediately when using graphical Apple IIGS software. A mouse should disappear into the experience. You shouldn’t have to think about how it’s being translated.

CRT processing offers an optional period-style display

The release adds GPU-powered CRT post-processing on macOS. Enable it and the emulator can apply effects that make the image resemble output from a traditional monitor rather than a perfectly sharp modern panel. The feature runs through the graphics processor and loads its shader resources while the application is running. Not everyone will want it. That’s fine.

Some users prefer clean pixels, especially when reading text or examining graphics closely. Others like the softer appearance and screen texture of an older display. GSSquared keeps the filter optional, so it doesn’t force one presentation style on everyone.

If the required GPU renderer isn’t available, the emulator falls back to its standard display instead of refusing to run. That’s the right behaviour. A visual extra shouldn’t get in the way of the emulator itself.

SecondSight support expands the Apple IIGS setup

GSSquared update also introduces early emulation of the SecondSight VGA card. SecondSight gave upgraded Apple IIGS systems access to VGA output and higher-colour display modes. The new implementation supports VGA text along with 8-bit, 16-bit and 24-bit graphics.

This remains an initial version, so users shouldn’t expect every feature or piece of software to work perfectly yet. Still, it adds another meaningful hardware option and gives developers a foundation they can improve over time. It also makes GSSquared more useful for testing software designed for expanded IIGS systems rather than only standard configurations.

High-DPI displays get better treatment

Modern screens create their own problems for older computer interfaces. GSSquared now scales its interface and on-screen information more appropriately on Retina and other high-DPI displays. Buttons, menus and status information should appear at a more sensible size instead of becoming tiny or inconsistently scaled. Fullscreen mode has changed too. The emulator now uses a borderless window rather than taking exclusive control of the display.

That usually makes switching between fullscreen and desktop applications quicker. It can also avoid the flickering, resolution changes and brief black screens that sometimes appear when software takes over a monitor completely. It’s not a glamorous change. It does make the emulator easier to use on a current laptop or desktop.

Audio and video fixes improve compatibility

A large part of the work in version 0.9.0 sits below the interface. The developers adjusted interrupt handling and register reads for the Apple IIGS Ensoniq sound chip. These fixes improve compatibility with software that depended on specific hardware behaviour and could previously produce broken sound or fail during playback. Rastan is one example of a game that now works after the audio changes.

The release also improves cold starts and resets. Attached devices now return to a more accurate state, allowing the system ROM to follow its expected startup process. Video fixes address double high-resolution output and edge cases in the scanner logic used by the Apple II and Apple II Plus. Other corrections deal with conflicts between Disk II and IWM drives, memory writes involving the PDBLOCK3 ROM, KeyGloo mouse synchronisation in 320-mode and errors that could appear when changing audio output devices. You won’t see most of these fixes in a menu. You’ll notice them when software simply works.

A stronger everyday Apple II emulator

GSSquared supports the Apple 2, Apple 2 Plus, Apple IIe, enhanced Apple IIe, a 65816-based enhanced system with super high-resolution video and the Apple IIGS ROM 01 platform. Pre-built versions are available for Windows 10 and newer, Intel Macs, Apple Silicon Macs and Linux through an AppImage tested on Ubuntu 22.

There’s also early work on a browser edition using Emscripten. It’s still a proof of concept, not a full web release, but it shows that the emulator’s design can stretch beyond traditional desktop builds. GSSquared 0.9.0 doesn’t rely on one oversized feature. It improves the complete experience. Profiles make complicated machines easier to manage.

The editor cuts down on manual configuration. Mouse and display changes make GS/OS more pleasant, while the deeper audio and video fixes help more software behave correctly. That’s what makes this release worth attention. It spends less time showing off and more time removing friction.