[Apple II/e] Most .po disk images fail to boot

[vanfanel]

Hi there again,

I have been trying some games on the fantastic Play-By-Year collection:
https://archive.org/details/apple-ii-pl ... tion-v-0.1

However, all of the games in .po format seem to fail to boot, even if .po is one of the extensions supported by the core.

Any idea on what's going on? Is .po support partial somehow?

Looking at the core docs in https://github.com/MiSTer-devel/Apple-II_MiSTer, I can't see anything particular about .po (PRoDOS floppies?) images... It refers to .2MG images, but these are HDD images, while .po are supposed to be floppy images.

[thorr]

Try renaming it to .dsk and see if it helps.

[Newsdee]

You can also try mounting them as a hard drive (which are also Prodos images)

[akeley]

Try renaming it to .dsk and see if it helps.

Nice trick! I've tried it on a few and it seems to work.

Generally I tried to include .dsk images as priority in this collection, so there shouldn't be many .po ones overall - but if there are it probably means I couldn't find a .dsk verison (same goes for .woz and any other format included there which doesn;t work on MiSTer)

And yes, some, as Newsdee says are actually hdd images, eg Minotaur (1981), though not sure how to mount them as such in core. Change extension to .hdv?

[thorr]

Try renaming it to .dsk and see if it helps.

Nice trick! I've tried it on a few and it seems to work.

Generally I tried to include .dsk images as priority in this collection, so there shouldn't be many .po ones overall - but if there are it probably means I couldn't find a .dsk verison (same goes for .woz and any other format included there which doesn;t work on MiSTer)

And yes, some, as Newsdee says are actually hdd images, eg Minotaur (1981), though not sure how to mount them as such in core. Change extension to .hdv?

If the file size is exactly the same as a typical .dsk, then I believe the filename is the only actual difference and the data is exactly the same (just rename it and now you have a real .dsk file). Back when I was a kid, I actually put a bunch of my favorite BASIC programs and games onto a floppy and then created my own .dsk file by connecting my Laser 128/EX to a PC via a serial cable. I went into Copy II Plus where I could examine the bytes of each sector on the floppy. I dumped the screen output a page at a time to the serial port by "printing" it. Then on the PC side, I wrote a QuickBasic program to read the text data and dump it into a binary file which became the .dsk file. I was then able to use this with an Apple IIe emulator that ran on DOS. I was super excited when it worked. So basically, a .DSK file is just a binary version of all the data on the floppy, byte for byte. A .po file is exactly the same size so therefore it is identical because there are no extra bytes to do anything with for a header, etc.

[vanfanel]

You can also try mounting them as a hard drive (which are also Prodos images)

Renaming the .po files .hdv seems to work! The core works perfectly with them as hdv it seems!

Which confirms your advise.

[vanfanel]

@Newsdee: However, .po/.do support seems... flaky.
For example, if you try to load this one --> https://archive.org/download/apple-ii-p ... ided%5D.po

... You will see this only loads like half of the times you try (ie: half of the times you reset the core).
Is that expected or could it be a bug?

[vanfanel]

@Newsdee: you have to rename https://archive.org/download/apple-ii-p ... ided%5D.po to .DSK, and then it loads half of the times you try.

As a .PO file, it never loads.

[Flandango]

@Newsdee: you have to rename https://archive.org/download/apple-ii-p ... ided%5D.po to .DSK, and then it loads half of the times you try.

As a .PO file, it never loads.

That particular image is not actually stored in a PO image format but actually in DO format (sector ordering).
When a PO image is loaded, it's processed differently then DO and DSK images by Mister so that's why it fails to load it properly.
When renaming it to DO or DSK, it, in essence, bypasses the PO processing and loads it properly.
Unfortunately, there is no automated/easy way to verify that a PO image is in fact a PO and not a DO/DSK image outside of the filename extension.

On a side note, I just tried it out on Mame too, and it too fails until you rename it to DO or DSK.
Hope that helps.

[vanfanel]

@Newsdee: you have to rename https://archive.org/download/apple-ii-p ... ided%5D.po to .DSK, and then it loads half of the times you try.

As a .PO file, it never loads.

That particular image is not actually stored in a PO image format but actually in DO format (sector ordering).
When a PO image is loaded, it's processed differently then DO and DSK images by Mister so that's why it fails to load it properly.
When renaming it to DO or DSK, it, in essence, bypasses the PO processing and loads it properly.
Unfortunately, there is no automated/easy way to verify that a PO image is in fact a PO and not a DO/DSK image outside of the filename extension.

On a side note, I just tried it out on Mame too, and it too fails until you rename it to DO or DSK.
Hope that helps.

Ahhh! I see. I must take note about this, too: some .PO are .DO under disguise!

Thanks, Flandango. But then again, it only loads sometimes... even if renamed. Doesn't it happen there?

[Flandango]

... it only loads sometimes... even if renamed. Doesn't it happen there?

I did not do intensive testing on it but once I named it as DO, I booted it up about 8-10 times and it worked every time.

[vanfanel]

... it only loads sometimes... even if renamed. Doesn't it happen there?

I did not do intensive testing on it but once I named it as DO, I booted it up about 8-10 times and it worked every time.

If you reload the core in between, I think you will discover it fails some times, specially first time after loading the core. Can you confirm this?

Also, another game that has the same exact problem (boots only half the times, fails specially after reloading the core) is https://archive.org/download/apple-ii-p ... %5Bb%5D.po

[vanfanel]

In fact, there doesn't seem to be a single Zork Zero set of disks that works correctly with the core...

[akeley]

In fact, there doesn't seem to be a single Zork Zero set of disks that works correctly with the core...

Yeah, it's strange, in fact I couldn't get it to run even in WinApple. Mostly gets stuck looking for Side 3, and the woz version reports some error.
It's supposed to be a 128k game in any case...is our core 128k?

[Flandango]

I tested both the Ultima image and the Zork Zero (the one you linked above), renamed both to DO files and they work each time I booted it up.
I tested the following scenarios....1- Initial Load of core, 2- Reload the core (by going to OSD->Core and re-selecting the Apple II core) and 3- by doing a Cold Reset via the menu. I did it over and over and it worked.
Now....how are you reloading the core? If you are resetting it by doing the CTRL-ALT-ALT method, it will not work...it needs to be a cold reset from the OSD.
Without looking at the code (since I don't have it front of me at the moment), it's most likely needed to be done that way to tell Main (who's doing the disk image processing) to reset pointers and what not for the disk image and simply resetting the core doesn't tell Main to handle it's business.

As for WOZ images, yeah they are not supported.

[akeley]

I tested both the Ultima image and the Zork Zero (the one you linked above)

Did you try all the Zork Zero disks? After Side 3 (needs to be loaded in Drive 2 apparently) I get "Dungeon - Internal error 80 - End of Session" message.

I meant using woz in an emulator btw.

EDIT: ok, this set (renamed to .do) works in microm8 emulator, so at least there's that. In AppleWin it fails the same way as in MiSTer.

Also, as an aside, what happened to coloured (artifacting) fonts? The core used to display them back in the day, now they're black and white.

[Flandango]

Sorry, I didn't try anything past loading the game and going just past the intro.

[akeley]

Sorry, I didn't try anything past loading the game and going just past the intro.

Do you mean just loading disk 1 and seeing the initial "choose input" screen? ("Enter the letter of pointing device [...]")

To load the actual game you need to use 3 disks. Sorry, just want to make sure we're on the same page and curious why this doesn't seem to work in MiSTer

[Flandango]

Sorry, I didn't try anything past loading the game and going just past the intro.

Do you mean just loading disk 1 and seeing the initial "choose input" screen? ("Enter the letter of pointing device [...]")

To load the actual game you need to use 3 disks. Sorry, just want to make sure we're on the same page and curious why this doesn't seem to work in MiSTer

Yes, I only tested to see if it boots. Sorry I didn't go past that Choose Input screen.
I just tried it and yes it fails on properly reading disk 3 from Drive 2.

Seems that either in the Core or in Main, having two disks mounted causes some kind of syncing issues. I don't have the means at the moment to debug it so sorry I can't be of much help at the moment.