GSSquared 1.0 puts the whole Apple II family in one emulator

Developer Jawaid Bazyar released version 1.0 of GSSquared, a cross-platform emulator that covers the 8-bit Apple II line and the 16-bit Apple IIgs in a single application. The software runs on macOS, Windows, and Linux, and a browser-based version is available without an installation.

Historically, emulating the Apple ecosystem meant keeping a folder full of different programs. You'd use AppleWin for 8-bit classics like the original Prince of Persia, and switch to GSport or KEGS to play 16-bit titles like The Bard's Tale on the IIgs. Outside of MAME, GSSquared is one of the only standalone projects to model both architectures in one place.

The floppy disk is now a tarball

The headline feature for version 1.0 is the .gs2pack format. A pack is a single file (technically an uncompressed tar archive up to 200MB) that holds a virtual Apple II and all the disk images it uses. When you open the pack, the machine boots. When you close it, any disk changes are written back into the file. Bazyar designed this so you can hand someone a fully configured machine in one double-clickable document.

That portability extends to the cloud. The desktop app and the web player can fetch packs served by arQyv. If you use the arQyv Cloud Storage service, playing an item from your collection writes the disk changes back when you leave the machine. The browser version also received a timing overhaul. It now keeps time with the Apple II frame rate (roughly 59.92 frames per second) instead of syncing to your monitor, meaning a high-refresh display won't accidentally run the machine at double speed.

Hardware accuracy and virtual modems

The update adds emulation for several specific expansion cards. An Apple IIgs can now take a Video Overlay Card in slot 3, which combines the two super-hi-res screens into a single 640x400 image. The Second Sight VGA card emulation now supports Host Text placed in memory, including tall layouts like 132x60. ProDOS 2.4.3 doesn't crash anymore when the newly emulated ThunderClock Plus is installed.

The 1.0 release also brings a long list of accuracy fixes to the core architecture. Switching the 65816 CPU's X or Y register to 8-bit width now clears the high byte exactly as a real chip would. The 6502 reset process was also tweaked so the stack pointer is only forced to zero on a cold boot, rather than on every reset. You can also create blank disk images directly from the file menu, supporting everything from 5.25-inch DOS 3.3 formats to 32MB ProDOS hard drives.

Network support includes a virtual modem that listens on TCP port 6502. A telnet client can ring the guest machine, and inbound sessions use a binary mode so classic ZMODEM and XMODEM file transfers actually work. I'm curious how many people are still dialing into Apple II bulletin board systems in 2026, but the infrastructure is there. The Sirius Joyport is also supported, mapping any gamepad face button to the fire button.

Source: gssquared.net, gssquared.net