Console Observatory 0.5.0: safer battery saves, steadier lessons and inspectors

Console Observatory is a native desktop Game Boy teaching lab. Run a game, pause it at any moment, and follow what happens in the CPU, memory, and graphics hardware.

What's new

Your game saves are safer

• A damaged or unrecognised .sav file is never loaded half-way and never overwritten automatically. The Cartridge panel says it is protected, and File › Save battery RAM as… lets you keep new progress somewhere else.
• If a save can't be written (for example, a read-only folder), the Cartridge panel shows the error with Save now / retry and Save elsewhere. Closing the app or opening another game then asks you first: save elsewhere, discard the unsaved progress, or cancel and keep playing.
• Saves made by other emulators with a real-time clock (older SameBoy, VBA, BGB formats) load correctly. Malformed ones are rejected safely; one such case could previously make the emulator core read past the end of the file data.
• Autosave now also runs while paused, so progress made by stepping is kept too. Restart keeps track of unsaved progress.

Inspectors you can trust in more situations

• Fixed: after about 37 minutes of continuous running, the timing calculation overflowed.
• On cartridges with several RAM banks, "last writer" now finds the write to this bank's byte, not the same address in another bank.
• Cartridge facts now follow the emulator exactly for unusual headers (multicarts, contradictory RAM sizes, TPP1), and the panel says when the effective controller differs from the header.
• Selecting a sprite follows its tile as the game animates it; picking a tile yourself pins it. Links from tiles and the memory map open the Memory panel. Clicking around while paused keeps the last activity numbers.
• The picture line says how long before the current CPU state it was drawn.

Clearer lessons

• Stepping, running, pressing game keys, or changing capture during the guided lesson now leaves it cleanly, so old explanations never describe a different state. Starting again resets to a known frame and checks each expected event before moving on.
• Lesson pages add short prediction and explanation prompts and spell out instructions in plain language ("copy A = 73 into player_x").

Download

Platform	File	How to run
Windows 10/11 (64-bit)	console-observatory-0.5.0-windows-x64.zip	Unzip anywhere and run console-observatory.exe; nothing else to install. The app isn't code-signed, so Windows SmartScreen may ask first: choose More info → Run anyway.
Ubuntu 24.04 (x86-64)	console-observatory_0.5.0_amd64.deb	sudo apt install ./console-observatory_0.5.0_amd64.deb, then start Console Observatory from the app menu.

SHA256SUMS.txt lists each file's checksum. The app runs offline; it needs no browser, server, or account. No commercial game is included; open your own .gb/.gbc files.

Good to know

• It emulates the original monochrome Game Boy (via the SameBoy core); no Game Boy Color mode, Super Game Boy extras, or sound output yet.
• OAM DMA is observed (the request, then a later check of sprite memory), not traced byte by byte.
• Tested on Linux and on Windows in CI; not yet on a physical Windows PC.

How these files were made

The Release workflow built both files from this release's commit after the same checks as CI passed on that machine: five test suites, the widget suite on the native platform, and on Windows a launch of the unzipped package with only System32 on PATH. CI also runs the engine suite under AddressSanitizer. Details: docs/VERIFICATION.md.