Thank you... I'm installing RSSI.... I'll try to figure out how it works. I once used IRC through a web-based interface, but I don't remember where it was.
I've been researching the memory structure of Stunts as it loads and I found the following data. Many of this, you probably have already figured out, but other stuff might be useful:
- Stunts has HDR, DIF and COD files for MCGA, TDY (Tandy) and CGA, but the DIF file is replaced by a CMN file for EGA. All COD files for some reason are about 64K long (though never exactly), DIF files are about 16K and the CMN file is about 128K. This cannot be just a coincidence! HDR files are unmistakenly EXE headers. They are 30 bytes long, but nevertheless correspond to EXE files whose code starts at byte 512. The space in between does not contain any code update, though. COD, DIF and CMN files are slightly compressed with a procedure that looks like a very basic kind of Huffman. This is exactly the same procedure used for 3D shapes compression, so it is already known, as cars are already being edited!! The actual sizes of decompressed codes are specified at the second byte of these files and do not match with the size estimate contained in the headers, which is much bigger.
- STUNTS_K.EXE, the crack, is lightly encrypted. The encryption system can easily be removed with UNP. The unpacker will ask for a passcode. First thing I thought worked: it's just "stunts_k". The resulting file is smaller than the encrypted one.
- STUNTS_K.EXE is loaded, keeping its environment MCB and code MCB. On top of it, STUNTS.COM runs, which also preserves its environment, reads the configuration file and loads LOAD.EXE into memory half-manually, apparently upgrading the code depending on the graphics card selected. LOAD.EXE runs. Environment is preserved again. LOAD.EXE reserves a lot of heap and no dynamic memory is allocated for variables. Only one extra MCB is allocated, but it is used to store only the sound driver, which starts at byte zero. If no sound card is selected, PC-Speaker driver is loaded anyway, but is not used. This last MCB takes up all the rest of the available conventional memory, even though it is not necessary.
- I have verified that the data contained in MCGA.COD and MCGA.DIF is not found in memory while Stunts is running. This is a confirmation that the information is compressed.
- Some variables are stored at positions that seem to be also variable respect to LOAD.EXE's starting code offset, even though they are within the same MCB. This is still a kind of mistery to me
Hope it's useful
