So let's say we have a simple .rom or .bin or .car file like Starraid.bin.
How does one make a .com .exe or .xex. ?
Well Ok, Star raiders is not simple though because it's a diagnostic cart which means it fires off before the OS has completed it's own initialization process. Somewhere in between almost done with that job, this particular cart just takes over, so loading of DOS by OS code isn't happening. NOT simple at all then.
Use a hex editor on these BASIC object files and compare them to the BASIC.ROM files they are related too. Maybe disassemble the object files to spot the twists and turns needed to just get BASIC to run as an xex file - can get very complex. Main issue going on here is that the display list is occupying cart area so E: needs to be re-opened after proper ram size is adjusted downward to move the display list.
I got my feet wet using disk editors on real floppies. A hex editor has the same look and feel, but the basics were learned observations of Atari files on disks. Don't know how you are going to pick it up as second nature without that hardware.
A real machine would have a major headache trying to emulate a bank switching cart like BASIC XL. The only reason it runs on emulators is because the emulator has that extra code and storage place to emulate the bank switching cart with, the real machine has only the cartridge hardware and it's missing.
Method might be better done with reverse order. DOS is booted which then goes looking for AUTORUN.SYS file(s) which then load the cart data. Files such as AUTORUN.SYS have headers that tell DOS where to place the code while having two unique places to RUN or INIT the loaded code. INIT address of 0x02E2, 0x02E3 is always run as soon as it is changed from RTS address pointed to by DOS as it loads memory as told to by the header. This is why AUTORUN.SYS files should only be using INIT address to run code and should always end with RTS instruction so that DOS will just resume loading the rest of the AUTORUN.SYS file. And this means AUTORUN.SYS files can be appended to do things in desired order. RUN address 0x02E0, 0x02E1 is jumped to only after the file is finished loading and IOCB is closed.
Cartridge also has INIT and RUN address but at the end of the cartridge space. Mapping the Atari pg 103,104 --- pdf pg 137,138
Executable files always start with FF, FF double bytes to indicate an executable file follows. Load to address pair comes next followed by ending address pair to load data to. Double FF can be repeated, which will be ignored as next in the file structure and/or you can have just another pair of load addresses, start and end. And this pattern can go on as many times as you need it to. RUN Address can be changed many times but the only one that is RUN is the last one loaded. It would be a headache WITH the real BASIC XL cart, without it, I have serious doubts it can be done on a real machine at all. You would need to write a custom banking system that used extended memory to hold the bank switched cart data and then move it along with changed banking address that is looked at every interrupt to see if a new bank is supposed to be there or not. Pure hell if you ask me so I really doubt anyone, if they have written such a thing, is here and now to give it away.
So very much easier to get a real BASIC XL cart. And then start pulling the hair out getting AUTORUN.SYS to play nice.
Would depend on the software bundled with it and by the overpriced appearance of the item itself, I doubt very much it has anything except the bare minimum that could qualify as meeting stated claims. And that would be the end of support. They don't have a list of compatible formats it can read ONLY? Doesn't smell nice here.
I would expect MAYBE DD DOS2 disks possible, but nothing else is very likely. And the numbers of those I have is negligible while already doable by other means like MS-DOS on Win98.
3 times the money will get you kryoflux well known to do just about anything Atari. Along with everything else.
Just my opinion but I smell a raw money grab on this one. Certainly would save my money up for the much better kryoflux if I needed to go here.
Yes to using any other 74LS138 for testing purposes.
Remove keyboard and try it without. SignGuy81's #3 might be the issue where SELECT and START are stuck on and you are looking at the Cassette boot screen. Which is waiting for you to press the spacebar IIRC, then it should beep to signal that you need to turn on the cassette player.
Try swapping out 4051 chips before tearing apart the keyboard, they go bad often enough to be the real issue here too.