Well, this was a long time ago for me so I am going to need to research this a bit before I can comment. I might need to look at this when I get home tonight if I can not figure it out here at work. I will need to confirm whether my games unload nicely or not.
What version of Atari800WinPlus are you using?
I know I converted all my images into "cart" images, but this was not to help load or unload the Rom. Some of my ROM files did not have the correct header information in them so when I started a game, the emulator would ask me whether the ROM was a "One chip 16KB 5200 cartridge" or "Two chip 16KB 5200 cartridge" because it could not tell since the header information was missing. Anyway, I converted the ROM files to have valid header information so the emulator could then figure out which type of cartridge it was from now on and no longer prompts me for this information when the game starts.
I believe this is how I start an Atari5200 game (using the Atari800WinPlus emulator) from within MALA:
atari800Win -5200 -ntsc -cart “C:\Emulators\RomFiles\Atari5200\Asteroids.car"
I am not using any special "unload" option in that command so I wonder if you are using a different version than I am. I am using the "Atari800Win PLus 4.0.exe" application which I downloaded from here:
http://atariarea.krap.pl/PLus/index_us.htm ** There is a chance my keyboard encoder (which can send many keys at the touch of one button) has been programmed to unload the cartridge via the menu options possibly. I need to look at this information when I get home. Although, if you are not using the same version of the emulator I am (see above) then you can try this version instead and see if it helps.
Also, you might want to try converting a ROM file into a CART file since maybe when a "cartridge" game is over it will detach the cartridge automatically for you. I am not sure about this, but it should be easy to test out.
Here is some extra "Atari800WinPlus" information which is documented in my "HowTo MALA" document (it includes converting a ROM to a CART file):
Atari800WinPlus emulator (Atari 5200 and Atari800XL)
I discovered the "Atari800WinPlus4.0" emulator and it plays all the Atari 5200 games for me (except Pitfall, Wizard of Wor, Star Trek) ..... it also plays all the Atari 800XL games and most importantly ........ interfaces with my TV in fullscreen excellently.
Thing is ..... I could not figure out what the command line parameters were for this emulator. It originally seemed like a windows only GUI application, however, I looked at the source code and found the following command line options were available:
-configure Update Configuration File"
-config <file> Specify Alternate Configuration File"
-atari Emulate Atari 800"
-xl Emulate Atari 800XL"
-xe Emulate Atari 130XE"
-320xe Emulate Atari 320XE (COMPY SHOP)"
-rambo Emulate Atari 320XE (RAMBO)"
-5200 Emulate Atari 5200 Games System"
-nobasic Turn off Atari BASIC ROM"
-basic Turn on Atari BASIC ROM"
-pal Enable PAL TV mode"
-ntsc Enable NTSC TV mode"
-osa_rom <file> Load OS A ROM from file"
-osb_rom <file> Load OS B ROM from file"
-xlxe_rom <file> Load XL/XE ROM from file"
-5200_rom <file> Load 5200 ROM from file"
-basic_rom <file> Load BASIC ROM from file"
-cart <file> Install cartridge (raw or CART format)"
-run <file> Run Atari executable file (COM, EXE, XEX)"
-state <file> Load saved-state file"
-refresh <rate> Specify screen refresh rate"
-nopatch Don't patch SIO routine in OS"
-nopatchall Don't patch OS at all, H: device won't work"
-a Use OS A"
-b Use OS B"
-c Enable RAM between 0xc000 and 0xcfff in Atari 800"
-v Show version/release number"
Important ROM file Information:
When I tried to play some Atari 5200 games, the emulator would make me choose whether the game was a "One chip 16KB 5200 cartridge" or "Two chip 16KB 5200 cartridge". After making the correct selection, the game would start, however, the prompting for information before a game starts is not nice for an arcade cabinet. Anyway, I found out that the ROM files I had were not in "true" cartridge format. Some of the game files were missing cartridge-specific file header information. Anyway, this emulator allows you to convert the game files so they have the proper header information. Once this conversion is completed, then the games start up right away without prompting for information. The next paragraph explains how to convert the files, which is very easy.
Originally my Atari 5200 game roms had an extension of "bin" (or "a52"). What you need to do is start each game in the Atari800Win emulator manually by starting the emulator and going into the "File\Attach Cartridge" menu and selecting the bin (or a52) game file. If the game is not considered a "true" cartridge file (ie: does not have specific cartridge header information included) then the emulator will ask you to select whether the game is a "One chip 16KB 5200 cartridge" or "Two chip 16KB 5200 cartridge". You can try either selection and see which one works. Once you find which one works you can go into the "Misc\Convert" menu and select "ROM to CART" option. This will allow you to convert a BIN (or a52) file to a cartridge (CAR) file by appending the correct header cartridge information to your file. Dont worry, it will not overwrite your existing ROM file but will instead ask you to save it to a different file ..... just save it to have a CAR extension. Once the file has been converted you can try to "attach" the cartridge (CAR) file via the menu and will now see that the emulator starts the game automatically.
Converting does not take long since the Atari5200 only has about 90+ games...... and the actual conversion is super quick.....