Appler has many built-in features accessed via function keys. F1 brings up the debugger, which is extremely handy if you're into 6502 assembly or want to get into it. It shows your currently running program code, the CPU registers, the stack, and memory.

To navigate to different sections press Alt plus the highlighted letter, e.g. Alt+R will switch focus to the Registers. The options along the bottom of the screen are accessed via the corresponding function keys. The Apple option will return you to the emulator, and is always the same as the key that brought you here, so for the debugger it's F1, in the file manager it's F2, etc.

Pressing F2 brings you to the file manager, which lets you load and save pieces of memory. Want to save exactly where you are in a game? This will save the whole state of the machine! We'll get back to it in a bit.

F3 brings you to the disk manager, which lets you load a virtual floppy disk in either of the two available drives. You can find software all over, check out this ftp mirror or apple2online for a huge selection. Keep in mind that there are many different disk file formats and software was written in some cases for a specific model of Apple II, so some won't work in Appler.

Let's play something! I'll start out with Zork - a classic text adventure that you should definitely play if you haven't already. Find the game on the apple2online site above - it comes with three disk files. DOSBox likes DOS filenames and Appler wants a .DSK extension, so put them in your Appler folder and rename them appropriately - ZORK1.DSK, ZORK2.DSK, ZORK3.DSK.

Launch DOSBox, then run Appler and push F3 to use the Disk Manager. On the right you can see the available disks. Drive 1 is highlighted, so push F2 to remove the current disk from the drive. Press the up and down arrow keys to navigate to the disk image, then press F2 to insert a virtual floppy disk. It should end up looking like this:

Press F1 to reboot the Apple II and load the game!

Don't get eaten by a grue!

Here are all of the commands for the emulator:

• F1 - Debugger
• F2 - File Manager
• F3 - Disk Manager
• F4 - Keyboard setup
• F9 - About
• F10 - Help
• Alt+Esc - Run a DOS shell, type EXIT to get back to Appler
• Alt+X - Quit

Continue reading to see how we can save the memory state and effectively save the game.