Once upon a time, I decided to put Final Fantasy 7 into my CD-ROM. There wasn't too much of interest, but the DAT files in the FIELD directory caught my eye. They were the text to the game, but it was scrambled in areas. After months of staring at the screen I was able to figure it out. More recently, I have been looking at various SNES ROMs which use compression. Each of these were compressed in a similar manner as Final Fantasy 7 had been. As such, I decided to write a document explaining it. For more information enter "LZW compression" into a search engine. In this compression, an 8-bit value is used to determine the nature of the following groups of data. A value of 1 indicated an uncompressed value. This means one byte is read from the input file and then written to the output file. A value of 0 indicated a compressed value. This means two bytes are read, from which a pointer to previous data can be generated. The pointer contains the length of the data to be retrieved as well as the offset for it to be retrieved from. Since pointers aren't used for 1-2 byte values, a value of 3 is added to the length. Here are some of the pointer formats I have seen: (On is the Offset's nth bit, Ln in the Length's nth bit) Dragon Ball Z - (One of the RPGs): O3 O2 O1 O0 L3 L2 L1 L0 | OB OA O9 O8 O7 O6 O5 O4 Final Fantasy 7: O7 O6 O5 O4 O3 O2 O1 O0 | OB OA O9 O8 L3 L2 L1 L0 Ogre Battle: L4 L3 L2 L1 L0 OA O9 O8 | O7 O6 O5 O4 O3 O2 O1 O0 Record of Lodoss Wars: O7 O6 O5 O4 O3 O2 O1 O0 | O8 L6 L5 L4 L3 L2 L1 L0 If you think you know of a ROM that uses this compression, please e-mail me the title of the ROM. For quicker results, include the URL to a web site I can obtain the ROM from. CzarDragon@Yahoo.com This text was brought to you by GSHI.org, unless someone else gave it to you, in which case it was only written by someone at GSHI.org. Heheh.