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 Post subject: Re: .IMG disk images??
PostPosted: July 11th, 2014, 11:05 pm 
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@kobushi

Excellent!

What tool have you used to extract the files?


I noticed the 5 files below seem to be missing on your list. Couldn't you extract them too?

?ove.e
?key00.e
?gatam.e
?ale2.e
?spi00.e

The "?" char means that the 1st char is missing, probably meaning that the file was deleted. But then they could also be undeleted, couldn't they? :)


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 Post subject: Re: .IMG disk images??
PostPosted: July 12th, 2014, 12:10 am 
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How did you get those 5 files? Maybe they're some of the 8 mystery files I couldn't access.
That first one is most likely "move.e", which is identical to "dog.e".

To extract the files, I used two methods.
First, I used d88edj (http://www.cug.net/~akatta/extra/my_too ... index.html).
Then, I used the 2DTools suite (http://www.jsdi.or.jp/~imp/) on a PC-9801 to convert the alley cat image to .2D format with 2d88, and then extract the files with pick2d.

The .e files from both of these methods were bit-identical.

Also, you asked about a PC-8801 debugger before. Try M88kai. There's an older version ready to use in the Neo Kobe emulator pack (viewtopic.php?f=3&t=1161), but I'm also attaching the latest version from 2014-05-20.
To update, just copy the new version into the M88kai directory in the NK emu pack, and delete M88.ini so it can be recreated.

Good luck!


Attachments:
M88kai_2014-05-20.7z [176.37 KiB]
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 Post subject: Re: .IMG disk images??
PostPosted: July 12th, 2014, 1:29 am 
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Quote:
How did you get those 5 files? Maybe they're some of the 8 mystery files I couldn't access.


Open the original alleycat.d88 image file using an Hexeditor. Then look at the address 72840h, where the directory is.

You can undelete the deleted files by replacing the first removed letter with a underscore "_" character on the hexeditor, and saving the file (take care to be sure that the Hexeditor is on overwrite mode, and not on insert mode).

Then run again the same tools you used to extract the files.

Thanks for the M88kai tip!

I tried it, and it seems to have some debugging features. But how do I run the code in step-by-step and set breakpoints? I had in mind a debugger similar to the one integrated in the Meka Sega Master System Emulator.

Don't get me wrong, I'm not complaining. The fact is that I'm an experienced Z80 programmer (~25 years on the road), and with a debugger like the one Meka has I think I could fix the AlleyCat problem. My guess is that it's some sort of copy protection.

I never coded for the PC88 though, so any tips on tools and documentation about its architecture would be a lot of help. :)


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 Post subject: Re: .IMG disk images??
PostPosted: July 12th, 2014, 2:17 am 
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Great, thanks, I extracted those 5 deleted files. I also tried to grab the 8 mystery files at the beginning, but no luck.
Attachment:
alley cat undelete files.rar [81.32 KiB]
Downloaded 230 times


_ove.e is identical to move.e and dog.e.
_spi00.e is identical to rspi00.e.
_ale2.e and _gatam.e look promising.
_key00.e is junk maybe? All bytes are FF.

Also, for debugging please try X88000. The one in the latest Neo Kobe emu pack is up-to-date. It has step, trace, and breakpoint functions, so hopefully you'll find it useful.

It's nice to have a Z80 veteran around! I am definitely not a programmer.


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 Post subject: Re: .IMG disk images??
PostPosted: July 12th, 2014, 3:02 am 
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Location: South Africa
sdsnatcher wrote:
. My guess is that it's some sort of copy protection.


It is copy protection I think - one old archive I have of it has a text file saying:

アレイキャット(protected)

[ Which Google translates sweetly as Array cat (protected). ;) ]

Kobushi - is there not a crack in any of those old Wizard88 or File Master disks?

Just on its behaviour - it seems to start, do an immediate disk access, then decide it is copy protected and do nothing further.

PS. I used to play Alley Cat a bit on a PC XT way back - glorious 4 colours - magenta, cyan, black white LOL.


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 Post subject: Re: .IMG disk images??
PostPosted: July 12th, 2014, 9:20 am 
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peter_j wrote:
Kobushi - is there not a crack in any of those old Wizard88 or File Master disks?

I think I tried that a couple years ago when the disk images were posted. But I might as well try again.

I found two filers with profiles for Alley Cat: Magic Copy and Expert88. Expert88 didn't work - the result was a 1KB d88 file (this might be an emulator problem). Magic Copy didn't work at first - there was a typo in the IF-THEN statement on line 10050. After I patched that, the disk was copied, but it still won't boot.

This leads me to conclude that this disk image is not a 1:1 dump of the original Alley Cat disk. If we had the original disk, the filers would probably work.

If anyone wants to try the filers, they're pretty self-explanatory.
Magic Copy: boot from the filer disk, press 0 for filer mode. Alley Cat is profile #1. Swap disks as instructed, then press Enter.
Expert88: boot from the filer disk, press 3 for construction mode. Alley Cat is profile #18. Swap disks as instructed, then press y.

Here are the filer disks, and the disk that Magic Copy produced. I also extracted the main backup routine and Alley Cat profile from each filer for reference. The code shows you exactly how to crack the disk. Now it's just a matter of figuring out why it won't boot.


Attachments:
alley cat filers.rar [254.62 KiB]
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 Post subject: Re: .IMG disk images??
PostPosted: July 12th, 2014, 2:54 pm 
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I tried my luck here with Expert88 and Magic Copy running on X88000, then compared the resulting image with the original using wxHexEditor.

- Expert88: Just a single byte at offset 1Ah was changed from 10h to 00h.
- MagicCopy: Changes the same byte at 1Ah as Expert88, then it patches some code at the beginning of the image. But it also changes lot of data (not code) in the end of the disk, which could mean that this copier is still buggy.

Judging by the results of Expert88 and MagicCopy, and considering that the areas that MagicCopy touched already contained a lot of consecutive NOP instructions, my guess is that the alleycat image we have was already copied and patched with Expert88. This is why this copier only changed a single byte: it patched what was already patched.

The conclusion is that either this is either (1) a bad dump, or (2) the game relies in some unknown PC88 feature that isn't yet emulated. The only way to confirm which one is true would be to try to run the image on a real PC88, but I don't own one.


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 Post subject: Re: .IMG disk images??
PostPosted: July 13th, 2014, 1:30 am 
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sdsnatcher wrote:
- Expert88: Just a single byte at offset 1Ah was changed from 10h to 00h.

That's just the write-protect flag in the D88 header, not the actual disk.

I tried Expert88 with several different emulators, didn't get anywhere.
M88: Empty 1KB image like before.
X88000: Result is identical to source disk.
j80: Freezes.

So maybe Expert88 is trying to do some kind of low-level disk writing that isn't emulated properly, or the disk is already patched like you said.


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 Post subject: Re: .IMG disk images??
PostPosted: July 13th, 2014, 3:44 am 
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The D88 looks very funny, and bad IMHO. If you look at offset 2A0 hex you have F7 F7 F7 in the cylinder, head and record number of the first recorded sector - impossible numbers.


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 Post subject: Re: .IMG disk images??
PostPosted: July 13th, 2014, 5:05 am 
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The F7F7F701 sector seems to be part of the copy protection scheme. There's a pointer to load that sector in the offset 11AA0h of the disk image.

I was able to fix the game. It was indeed some sort of copy protection that was causing it to freeze. So here's a small gift for you all. :)

The speed is very high, and I'm not sure why. But at least now the game runs on QUASI88 and X88000.


Attachments:
alleycat_fixed.zip [85.65 KiB]
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 Post subject: Re: .IMG disk images??
PostPosted: July 13th, 2014, 5:29 am 
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sdsnatcher wrote:
I was able to fix the game. It was indeed some sort of copy protection that was causing it to freeze. So here's a small gift for you all. :)

The speed is very high, and I'm not sure why. But at least now the game runs on QUASI88 and X88000.


Amazing!!! :D

Thank you so much for your efforts.

Runs in M88 too - just slow the clock speed to about 2MHz.

If anyone wants to remember the old PC sound ( this PC88 version is a bit primitive :wink: ) you can play it at
http://en.wikipedia.org/wiki/Alley_Cat_%28video_game%29

Stunningly great effort! Love them mousies.


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 Post subject: Re: .IMG disk images??
PostPosted: July 13th, 2014, 10:32 am 
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Yer a wizard! :)

To get the game to run at the correct speed, use M88kai and set up the emulator like an original model PC-8801.
Use V1(S) mode, 4 MHz CPU speed, and turn the wait options on (particularly memory wait).

Unfortunately I can't get it to work in j80, it seems to get stuck on a sector not found error.

This game is also very sensitive to which disk.rom you use.

Regardless, the game runs! Thanks again sdsnatcher!


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 Post subject: Re: .IMG disk images??
PostPosted: July 15th, 2014, 12:07 am 
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I looked over the last two problem files in this set.

molemole.img is garbage. The disk is almost completely empty, except for a ~2KB chunk that is also found in a working disk image of Mole Mole by Crossmedia Soft. So it's very likely a failed dump of that game. This file is not fixable - the data just isn't there.

murder.img is definitely Murder Club. The image contains two disks, and the second disk is nearly identical to disk #2 of a working copy of Murder Club. You can even play the game using the working copy of disk #1, and the murder.img disk #2. It might be possible to fix disk #1, but good copies of this game already exist, so there's no need.

So that takes care of all these .img files. Everything is playable, or a working copy already exists.


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