GSSquared

What’s new

Highlights from recent GSSquared Apple II emulator releases. For deep technical notes, see the project documentation and GitHub releases.

Version 1.0 ·

GSSquared 1.0

It’s done!

  • GS2 packs One .gs2pack file holds a machine and the disk images that go with it. Open it by double-click, by dragging it onto GSSquared, from File → Launch Config…, or from the command line. When the session ends, GSSquared writes the pack back so guest disk changes stay with it. While it is running, the drive button lists that pack’s images. macOS, Windows, and Linux open .gs2pack files with GSSquared. A pack may be up to 200 MB.
  • arQyv packs and the web player The desktop app and the browser player can fetch a pack that arQyv serves. With arQyv Cloud Storage, playing an item from your Collection writes disk changes back when you leave, or when you choose File → Save to Collection. At gssquared.net/live, a #pack= link starts that machine. The web build also keeps time with the Apple II frame, so a high-refresh display does not run the machine faster.
  • .gs2 documents A .gs2 file has its own icon, and macOS, Windows, and Linux open it with GSSquared. Double-click to launch that machine. On a IIgs, battery-backed RAM is stored in the file. Machine profiles you create live in a GSSquared folder in your Documents.
  • Video Overlay Card An Apple IIgs can take a Video Overlay Card in slot 3. It shows a 640×400 super-hi-res picture by combining the two super-hi-res screens into one steady 60 Hz image.
  • Second Sight Host Text With a Second Sight card, a program can show Host Text it places in memory — including tall layouts such as 80×43, 80×50, and 132×60 — a mode where the card’s GPU draws the picture, and a text mode fed as a stream of words. Those pictures sit inside a border so they fill the same window area as ordinary Apple II video.
  • ThunderClock Plus The ThunderClock Plus is emulated, including its timer interrupt and the firmware utilities ProDOS uses to read the clock. ProDOS 2.4.3 no longer crashes when the card is installed.
  • Inbound virtual modem With the Modem attached, GSSquared listens on TCP port 6502. A telnet client rings the guest. ATA answers, ATS0=n auto-answers, and the guest sees carrier detect for as long as that connection is up. Inbound sessions use a binary telnet mode, so ZMODEM and XMODEM transfers work.
  • Blank disks, and a round of fixes File → New Disk Image writes a blank 5.25″, 3.5″, or 32 MB hard-disk image. Serial bytes arrive at the baud rate the guest selected, a WOZ track with no data can be written so Locksmith can nibble-copy onto a blank WOZ, and the Uthernet II no longer drops network data that arrives faster than the card can take.

Version 0.11 ·

GSSquared 0.11 — talk to the real machine

This release is about connecting the virtual Apple II to the host: real serial ports, print-to-clipboard, Host FST on Windows — plus CRT shaders on Windows and Linux, Second Sight Apple II text, CD-ROM volumes, and a large round of IIgs timing and MMU accuracy.

  • Host serial ports Attach a real host UART to IIgs SCC or Super Serial from the Control Panel or config editor — macOS /dev/cu.*, Windows COMn, Linux USB serial. Guest baud, data, parity, and stop bits pass through; unplugged dongles stay attached and retry.
  • Print to clipboard Serial and parallel ports can attach a Clipboard device. Guest output is copied to the host clipboard after a short idle or Ctrl-Reset, with a toast for the byte count.
  • CRT shader on Windows and Linux The GPU CRT look that was already on macOS now ships on Windows and Linux. Toggle with Display → CRT Shader or F7 — no extra compiler SDKs required.
  • Host FST on Windows Share a host folder with GS/OS as :Host on 64-bit Windows. ProDOS type/auxtype, Finder info, and resource forks live in NTFS Alternate Data Streams.
  • Second Sight Apple II text With a Second Sight card, Display → Second Sight Text renders 40- and 80-column Apple II text through the card’s VGA path.
  • CD-ROM and APM volumes Mount .iso CD dumps (always write-protected). Apple Partition Map images expose each ProDOS and HFS partition as its own SmartPort unit — the usual path for 1990s IIgs CD-ROMs.
  • IIgs accuracy and paste Timing and MMU fixes (including textfunk), ludicrous-speed video that still scans, GS/OS mouse tracking on 640-pixel SHR, and Edit → Paste Text on the IIgs ADB path.

Version 0.10 ·

GSSquared 0.10 — plug it in

This release expands what you can plug into a virtual Apple II: Ethernet, serial, Host FST file sharing, and Mouse III — plus a full Apple IIgs ROM 03 machine, everyday quality-of-life tools, and a pile of accuracy fixes for sound, mouse, memory, and floppy behavior.

  • Apple IIgs ROM 03 A first-class ROM 03 machine alongside ROM 01, with correct 256K ROM mapping and GS/OS boot fixes so ROM 03 systems are usable out of the box.
  • Uthernet II Ethernet for the Apple II and IIgs via slirp — works on macOS, Windows, and Linux with no host TAP or bridge setup for typical use.
  • Super Serial Card SSC emulation for serial I/O, with in-app connection management shared with other serial and parallel devices.
  • IIgs Host FST Share files with the host from GS/OS. Mount the built-in drivers volume from the menu to install Host FST and the host driver.
  • Apple Mouse III New Mouse III card support — Mouse II setups redirect to the III implementation.
  • Screenshots, HUD, and stereo Save a screenshot straight to a file, hide the stats overlay and drive icons when you want a clean screen, and Ensoniq DOC stereo output with stereo drive-seek effects.

Version 0.9 ·

GSSquared 0.9 — make it yours

This release is about fitting the emulator to how you work: custom hardware profiles, better GS/OS mouse feel, optional CRT post-processing, and more polish across Mac, Windows, and Linux.

  • Custom system profiles Define a machine in a profile — platform, cards, storage, video — then launch it like a first-class system. Edit profiles in-app when you want to tweak without leaving the emulator.
  • Smoother GS/OS mouse tracking More reliable pointer sync, including when letterboxing or CRT bezels are in play.
  • CRT post-processing Optional GPU-based CRT look for a more authentic display (with a clean fallback when needed).
  • SecondSight VGA card (initial support) Early emulation for SecondSight on supported setups.
  • High-DPI and desktop polish Better behavior on modern displays across host platforms.
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