DjayBee

Look there for phaeron's thoughts about this: http://atariage.com/forums/topic/256683-altirra-280-released/?p=3587479

My images seem to work correct, so here is their story. While comparing Datasoft dumps from Farb's torrent and Atarimania I saw that the booting process of Lost Tomb looked very similar to that one of Mr. Do!. Lost Tomb actually uses (at least) two of the four protection checks from Mr. Do!. This is true down to the binary code level and in-memory addresses. Comparing the disk images showed that the loading code is identical except for three boot sectors. But it showed also evidence that Lost Tomb unlike Mr. Do! has no protection on track 40 of the disk. In Atarimania's Lost Tomb the first protection (duplicate sector $11) was patched out but the second one (track alignment) was not. The track alignment is verified by a VBI which counts the time it takes to get four times from sector 1 to sector $23 and keeps the result in memory location $113 but does no comparison or other verification of the result. I ran the game until somewhere in level 2 and there was no further access to $113. I then "uncracked" the first protection and put the data sectors of Lost Tomb onto the ATX disk image of Mr. Do! and alas the "Frankendisk" - how I call these hand-crafted ATXs - worked. Furthermore I verified that the VBI counter is the same for both games. Its value is $38 for the protected ATX and >$40 for an ATX with unaligned tracks. Atarimania states that their tape version works fine, but the disk dump crashes sometime later in the game. This fits to my observation that there is no access to memory location $113 (at least) until level 2. I then loaded the tape image in Altirra and found address $113 to be set to $3B. This made me quite confident that this memory location is the key to a working disk version of Lost Tomb. Disclaimer: Because of the very different boot sectors I am not confident that "my" ATX is a completely rebuilt/recovered image of Lost Tomb. But it is far more than not having any working disk version of the game. And "my" ATR is version with both protections cracked. If someone owns an original disk of Lost Tomb then please contact me to verify if it too contains protections three (second check for the duplicate sector) and four (duplicate, bad and weak sectors on track 40) from Mr. Do!. Lost Tomb (1984)(Datasoft)(US).zip

Try the attached ATR. Lost Tomb.atr

Can somebody please try if the attached DISK version does work correct? Lost Tomb.atx.zip

Original Zaxxon verifies the OS checksum and only accepts unmodified OS-A and OS-B. You made me aware of this when I complained that Farb's then latest dump did not work for me.

This is correct. Example: Broderbund's 1983+ protection (i. e. Gumball or Karateka). It reads a sequence of its duplicate sectors twice. The first read uses some small delays between the reads and yields the "hidden" sectors, whereas a normal sequential read of the sectors yields the "public" sectors. I tried to write a little XEX to extract the hidden ones and could not find a common delay to accomplish this.

These are identical except for these two differences: Released version: end of VTOC sector: "V1.0 100" protection: sectors 364, 380, 560, 592, 720 (missing) internal version: end of VTOC sector: "uSOFT V1.0 140" protection: sectors 364, 380, 560, 592, 720 (bad CRC) Altirra v2.81 shows a strange behavior with the internal version: For the bad sectors with "LFE DISK" it does not even show that these are accessed.

Thanks for your detailled explanation.

phaeron, would it be possible - either to expose the real disk emulation via an API to external programs like RespeQt? - or to make a library from it which could be linked to disk emulators? Then it would be possible to create ATX images using a Happy drive and a PC - without Kryflux or ijor's VAPI imaging tool.

Crack for Virtuoso Play Mode Sampler Virtuoso Play Mode Sampler v2.1 (1985)(Enhanced Technology)(US)p.atr

Find attached a copy protected "Frankendisk" created from an ATX for SIlent Service which uses the exact same protection. I kept the last track from this image and replaced everything else with Kevin's dump. The protection consistes of sectors with bad state and also duplicate sectors. Btw.: I have the impression that it works only on XLs and XEs. A crack will follow. It takes a little longer to do it. Virtuoso Play Mode Sampler v2.1 (1985)(Enhanced Technology)(US)p.atx.zip

How far did you get with this? If you send the results to me then I will go ahead.

Yes, this one is the Atarimania dump and is much older. The crashing one was added only to the latest torrent in Juliy. This dump has the same issues some of the MicroProse titles had which use the same protection. It has a missing sector 707 instead of a "long sector". SInce the status codes do not match, the protection fails. Since reconverting has solved the problems for the MicroProse titles, this will most probably work for Rescue On Fractalus as well.

Try the attached one. Rescue on Fractalus! (1985)(Activision)(GB).zip

Post your schematics and I will compare them to my drive. Looking "behind" the perfboard is not possible because 1. I expect the chips to be sanded and more so 2. the board has been fixed by glueing the chips to the 810's logic board.

Cool, guys. TNX

Yep, this is correct.

Check the photos for it. I just don't know the currently set value for the potentiometer.

If you check the photos a few posts above, you should be able to follow the wire wrap and find out which (address) lines are the input for the bank switching logic. I made the photos intentionally so that all wires are visible. Maybe somebody will be able to guess which TTLs are used.

Looks much better. Complete "HAPPYCOMPUTING" string and only twice this time. happy810dump.zip

Stay tuned, I will go ahead; I just was not at home yesterday - and currently am at work. Since I have pulled my 810 from storage, it would not make sense to stop now.

Try the attached images. I found a second different version of Ballblazer and could not apply the same cracking scheme. So I decided to redo the first one as well. But it might also be because Ballblazer uses its own SIO-implementation which relies on exact disk drive status codes. Ballblazer (1985)(Epyx)(US).atr Ballblazer (1985)(Epyx)(US)a.atr

It looks like this one has worked, but it took very long. Each of the 96 "Q"-commands took 20 seconds. Find attached the dump and (this time the correct) RespeQt log. Ijor was right that the one yesterday was wrong. Sorry for that. happy810dump.zip

It did not work. Find attached the RespeQt log and the result, which looks like parts of DUP.SYS. The sound while your program was running sounded like the hissing you hear when the drive NAKs something. Also find attached an archive with pictures of the mod. The two small ICs are both 14-pin and have the notch pointing upward. The RAM consists IIRC of two 2k static 6116 RAMs. The blue wire is for the speed control which uses a 22k potentiometer. I keep my fingers crossed that the drive still works after disassembling the PCBs; haven't tried yet. dump.zip BoardPicsHappy810.zip

I am not sure if the game runs well, but the German Second City from Atarimania is the only one which does not crash the game immediately. I could load it with any of the images of Targ i have Atarimania: Novagen,German and UK - set video to PAL Farb: Datasoft, US - set video to NTSC