Cracking old PC Booter games to work in DOS

Getting old DOS games working on modern hardware. (DOSBox topics belong in DOSBox areas below, not here).

Cracking old PC Booter games to work in DOS

Postby ModernMajorGeneral » 2018-12-23 @ 21:41

Hello there. I am (not really) kind-of new here, so apologies if I posted this in the wrong section. I am writing here because I want to crack the PC booter game Microsoft Adventure in order for it to work on DOS. I am wondering what I will need to do that.

I have looked through several downloads of the game, but they only have an .IMG file, which you need to boot. So, I want to make so that Adventure can be cracked. This has been done with games like Satan and Sid Meier's Pirates, so this should be feasible.

Thank you, and have a merry Christmas!

-Ross
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Re: Cracking old PC Booter games to work in DOS

Postby cyclone3d » 2018-12-23 @ 23:31

Burn the .img file to a floppy disk or use a utility to extract the files from the .img file.
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Re: Cracking old PC Booter games to work in DOS

Postby ModernMajorGeneral » 2018-12-24 @ 00:12

Hi there Cyclone. Thanks for the quick reply. The problem is that the program I would normally use (PowerISO) can't process PC Booter images.

Instead giving an error when doing so. Thus I am wondering what I should do: Should I use new software? Your help would be appreciated. Thanks and have a Merry Christmas

-Ross
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Re: Cracking old PC Booter games to work in DOS

Postby darry » 2018-12-24 @ 00:46

Try Winimage
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Re: Cracking old PC Booter games to work in DOS

Postby ModernMajorGeneral » 2018-12-24 @ 12:16

Nope, WinImage does not work either. Comes up with an error. Saying that it can't process it. Should I try something else? Or am I doing something wrong? Your quick replies and help is greatly appreciated.

Thanks, and have a Merry Christmas!

-Ross
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Re: Cracking old PC Booter games to work in DOS

Postby Zup » 2018-12-24 @ 12:24

PC Booter games usually load data via low level routines (i.e.: reading sectors), so they don't need (and usually won't use) a file structure.

Instead of "loading game executable" they do "read tracks 2 to 10 and put it on RAM address 0", or instead "reading level 1 file" they do "read track 15, sector 1". So it's not strange that you don't find any file on it.
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Re: Cracking old PC Booter games to work in DOS

Postby kjliew » 2018-12-24 @ 12:48

You could probably analyze the IMG loading mechanism from a virtual machine that provides host debugger interface to trace IBM PC boot from boot sector. IIRC, the IBM PC boots with boot sector at 7C00:0000. QEMU and Bochs are good VM candidates for such tracing. Once you know how the game was loaded into memory, then you can capture the RAM image and write a simple DOS START.COM to boot the image from DOS. This is assuming that the booter game uses a one-shot boot from IMG and runs from memory thereafter. If the game requires disk access during runtime, then the solution would be more complicated. It would require an IMG starter from DOS that hooks INT13H and translate the direct disk sector accesses into IMG file accesses.
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Re: Cracking old PC Booter games to work in DOS

Postby Azarien » 2018-12-31 @ 15:49

kjliew wrote:You could probably analyze the IMG loading mechanism from a virtual machine that provides host debugger interface to trace IBM PC boot from boot sector. IIRC, the IBM PC boots with boot sector at 7C00:0000. QEMU and Bochs are good VM candidates for such tracing. Once you know how the game was loaded into memory, then you can capture the RAM image and write a simple DOS START.COM to boot the image from DOS. This is assuming that the booter game uses a one-shot boot from IMG and runs from memory thereafter. If the game requires disk access during runtime, then the solution would be more complicated. It would require an IMG starter from DOS that hooks INT13H and translate the direct disk sector accesses into IMG file accesses.


Also things like EMM386 may complicate this further.
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Re: Cracking old PC Booter games to work in DOS

Postby BloodyCactus » 2018-12-31 @ 16:27

write an INT 13h trap and just load whole image into memory (its what, a 360kb disk?). just write an emu for in13h to trap readds and fake boot it.

or use flopper http://www.oldskool.org/pc/flopper

*edit* the image boots in dosbox just fine (boot msadvent.img)

*edit 2* damn its one of the worst ports of Adventure I've ever seen.
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Re: Cracking old PC Booter games to work in DOS

Postby digger » 2019-1-14 @ 01:08

I remember launching some DOS games as .COM files that I couldn't exit without a systen reboot. Many years later I would learn through sites such as Vogons and Mobygames that those games were originally booter games. Most booter games are earlier games that were small enough to fit in a single 64k segment. It shouldn't be too hard to convert such games to .COM files. Be careful about the booter games that write their high scores directly to certain sectors of the disks, though. ;)

Also, I remember visiting someone who used some kind of launcher from DOS to run booter games from the floppy without having to reboot a system. I'm sure a variant could be made that could launch booters in IMG files from DOS as well. :)
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