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Text File | 1998-02-28 | 14.1 KB | 335 lines

xDMS version 1.1 Released in 18-Feb-98 Introduction: ------------- Some time ago I started using UAE and Fellow Amiga emulators in the PC, while still using my Amiga. Both emulators are very nice, and I started testing some of my old games and demos on it. But a thing annoyed me. I have a number of CDs with demos and other software, with hundreds of disk images compressed with DMS. DMS was always the Amiga 'de facto' standard for storing copies of non-dos disks, as used by most games and demos. But the emulators required the Amiga software to be in uncompressed disk image format (now known as .ADF) or disk images compressed with gzip (ADZ). To use my DMS archives in the emulators I had to uncompress them with DMS inside the emulation, saving it as an uncompressed disk image in the PC hard disk. It was very boring, and also a waste of time and hard disk space, since I could not leave the files in the CDs. I thought a much better solution would be to add direct support for DMS files in the emulators itselves, in the same way as they support gzip compressed images. But as DMS uses a proprietary format, I thought DMS support in the near future would be unlikely. So I decided to do something myself and began to study the inner workings of DMS. After some days of hard work, I wrote a portable DMS unpacker, xDMS. xDMS is more useful for users of Amiga emulators, but can also be useful for actual Amiga users too. In fact, the extract command of xDMS can be very useful to actual Amiga users, just need an update of readdisk. xDMS Features: -------------- Supports decompression of files compressed using all known DMS compression modes, including old and obsolete ones, and also encrypted files, for 100% compatibility. Can test DMS files integrity, view file informations and show attached Banners and FILEID.DIZ . Can generate standard disk images and compressed disk images, using gzip, if you want to store your files in ADF or ADZ formats. Can extract the files contained inside the DMS archives, if the compressed disk is an AmigaDOS disk, using readdisk made by Bernd Schmidt. Can process multiple files in batch with a single command, and also use stdin and stdout for input and output of data. Instalation: ------------ xDMS was written in ANSI C and should work with most ANSI C or C++ compilers and platforms with minor or no changes. It was tested under Linux with GCC, MS-DOS with DJGPP and Amiga with SAS/C and worked well, 0without warnings. To compile it with GCC or DJGPP you can just use make with the supplied Makefile. For other compilers you may have to modify it slightly. A smakefile for SAS/C is also supplied. After a successful compilation you can install the generated executable somewhere in your path. You also need to install gzip and readdisk if you want to be able to create gzip compressed disk images and extract files from DMS. gzip is available in most public domain software libraries. Readdisk is supplied with UAE. You probably already have both. Also, as I'm sendind this program to UAE and Fellow authors and allowing them (or anyone else) to include it with their programs and change it in any way, perhaps xDMS just came together with your emulator, and was installed with it and directly supported. In this case you have nothing to worry. Usage: ------ xDMS is a shell utility program. When executed without arguments, it shows an usage screen. The template of xDMS is the following: xdms [options] <command> {<dms_file[.dms]> [+output]} Arguments inside [] are optional. Arguments inside <> are required. Arguments inside {} can be used one or several times. A command is indicated by a letter and can be one of the following: t : Test DMS archives u : Unpack DMS archives to disk images z : Unpack to disk images and compress it with gzip x : Extract files inside DMS archives using readdisk v : View DMS archives information f : View full information d : Show attached FILEID.DIZ b : Show attached Banner If the supplied input DMS file name doesn't have a .DMS or .dms extension, a default .dms will be appended to it. The output argument is optional and specifies a file name or a directory for each unpacked file. If the output filename is not supplied, it is generated from the input filename. If the generated file is a standard disk image it will have the .adf extension. If it is a compressed image the extension will be .adz . If you supply an output file name, no extension will be added. By default, files are unpacked to the current directory, unless you specify another directory with the output file name or use the -d option. Commands z and x respectively need gzip and readdisk instaled in the current path, or it will fail. When extracting files with x option, xDMS will call readdisk and it will reconstruct the tree of files and directories contained inside the DMS compressed disk image, starting in a directory with the same name as the volume name of the disk in the DMS file. This command can fail if xDMS can't execute readdisk, or if the dms compressed disk is not an AmigaDOS disk. The current version of readdisk supplied with UAE 0.69 only supports old OFS Kickstart 1.x compatible disks, reporting any of the newer formats introduced with AmigaOS 2.0 or newer as non-dos disks, while they actually are. The v commands show some information contained in DMS files, as the version of DMS that created it, the type of the disk, date of creation, number of tracks, etc. The f command also shows additional tracks informations. The b command shows the banner, if the file contains one. A banner is a text that is displayed when DMS unpacks a file and usually contains informations about the group/BBS/person that made it. The f command shows the FILEID.DIZ, if found in the DMS. It is a text that identifies what the DMS file contains. You can also supply as input filename stdin and/or +stdout as output. in this case xDMS will read the data from the standard input and/or send it to the standard output. You can supply multiple input and optional output files and use wild cards. When using wildcards, the +output argument will affect only the last file name expanded from the wildcard. To supply a global destination directory you must use the -d option. All commands and options are not case sensitive. You can also supply one or more (or none) of the following options: -q : Quiet -v : Verbose -d <destdir> : Set destination directory -p <password> : Decrypt encrypted archives using password When more than one option is supplied they must be separated. You can't use something like -qd dir . The quiet option suppresses all messages usually emited by xDMS, including error messages. It is mostly to be used when xDMS is called from inside emulators or some type of front-end. The program that calls xDMS can verify if the operation was successful checking the return code of xDMS. It will be 0 if the operation was successful or not 0 if it failed for one or more files. The verbose option makes xDMS display more messages than it usually does, including a progress indicator when unpacking files. This indicator is only useful if you have a very slow computer. The -d option specifies a global destination directory. This directory name is added before the name of any output file or output directory supplied with +output in the command line. The -p option uses a password to decrypt the dms files if they are encrypted. DMS uses a very lame encryption algorithm that could be easyly cracked. In fact, if the file is encrypted, and contains a banner, you can unpack it with any password. Some examples: xdms u foo.dms This will unpack the file foo.dms in the current directory and save it as foo.adf, also in the current directory. xdms -v -d /tmp/tst u foo +bar.dsk This will unpack the file foo.dms in the current directory and save it as /tmp/tst/bar.dsk . Aditional messages and a progress indicator will be displayed. xdms f ram:Hardwired1.dms (in the Amiga or inside Amiga emu) This will show informations about the file Hardwired1.dms in Amiga's Ram Disk, including tracks information. xdms -p treva u tst1 tst2 +tstdir/ttt tst3.DMS +stdout >tora This will (try to) unpack the files tst1.dms, tst2.dms and tst3.DMS in the current directory. If any of them is encrypted xDMS will try to decrypt it using the password "treva". tst1.dms will be unpacked as tst1.adf, tst2.dms as tstdir/ttt and tst3.DMS will be unpacked to stdout that is redirected to file tora. xdms -d /home/apele/uae/demos z /mnt/cdrom/*.dms (under Unix) xdms -d c:\emul\fellow\demos z f:\*.dms (under MS-DOS) This will unpack all files with the dms extension in the root directory of a CDROM disk, pack it again using gzip and save it in another directory. The generated files will have the .adz extension. xdms -q x tst This will (try to) extract the files contained inside the tst.dms file. The files and directories will be extracted to a directory with a name equal to the volume name of the disk contained in the dms file. No messages will be displayed. xdms -d stdout u *.dms >bigfile This will unpack all the dms files in the current directory and save them all to a single file. xdms -d /home u apele +apele/yourfile.adf trevor +trevor/yourfile.adf This will unpack the file apele.dms in the current directory and save it as /home/apele/yourfile.adf . Will also unpack the file trevor.dms as /home/trevor/yourfile.adf . cat tst.dms | xdms u stdin +stdout | strings | more This will display the ascii strings inside the unpacked dms file. In this case, xDMS is used as a filter. Known problems: --------------- If you try to extract the files (using the x command) of a DMS archive that contains a disk in one of the disk formats introduced with AmigaOS version 2 or newer, it will fail. Also, if you try to extract the files under MS-DOS it will almost always fail. It's not a problem in xDMS. It is a problem in the current version of readdisk. It only suports OFS disks. Another problem of readdisk is that it fails when executed under MS-DOS and the DMS archive contains files with names invalid to MS-DOS rules. If your Amiga disk compressed in the DMS archive contains a file named as Amazing_Amiga.txt.info, it will fail. It works under Unix. Under MS-DOS readdisk also changes the current working directory after its execution, if you specify an output directory to it. This can cause some problems too. I was thinking about adding internal support to extraction of files to xDMS, with support to all Amiga native filesystems, or write a replacement to readdisk, but now I think I will just wait for Bernd Schmidt or someone else to update readdisk. xDMS doesn't perform internal expansion of wildcards, but expects the shell (or the compiler) to do it. It is the usual under unix. But if you use it in a system where the shell does not perform wildcard expansion and your compiler also does not generate code to perform it, then wildcards will not work. This is the case, for example when using xDMS in the Amiga, under the standard Amiga Shell, when compiled with SAS/C. I think Amiga GCC adds wildcard expansion to the program it compiles. The same applies to xDMS compiled with compilers like TurboC under MS-DOS. DJGPP for MSDOS generate code to expand wildcards. Acknowledgements: ----------------- xDMS uses source code fragments or informations from the following public domain or freeware programs: Unix LHA by Masaru Oki : xDMS Heavy mode decrunch functions are based in lha static lzh functions. DMS used parts of LHA and LZHUF in the first place. LZHUF by Haruyasu Yoshizaki : xDMS Deep mode decrunch functions are based in LZHUF. testdms by Bjorn Stenberg : I got some initial information about the DMS headers with testdms, and also the CRC calculation function. xDMS also calls, if available, gzip made by Jean-loup Gailly / Free Software Foundation, and readdisk made by Bernd Schmidt <crux@pool.informatik.rwth-aachen.de> Last comments: -------------- I hope you find xDMS useful, be you using it with an actual Amiga or with an emulator to remember the golden days of the Amiga. I wrote it mostly because I thought it would take ages for DMS support to be added in the Amiga emulators as its authors were busy with other issues. I also thought nobody else would do it. Later, when xDMS was almost ready, I discovered I was completely wrong. David Tritscher was doing the same thing I was, and released a portable DMS decruncher in Aminet called undms (also spread by some users as dms2adf). I tried his program and it appears to work nicely. But xDMS has far more features ;) Also, xDMS should not be cofused with xdm, the XWindows Display Manager, or with some of type of database management software package. Copyright: ---------- xDMS is released as public domain software. You can spread it, modify it and use it in any way you like. You can do anything with it without asking me first. But I would like to know if you do something cool with it. How to contact the author: -------------------------- If you have some problem, you can contact me by e-mail. But first make sure you have read all this documentation, to not waste my time with silly questions. If you have found a bug in xDMS please contact me. If the bug is in readdisk, contact Bernd Schmidt. Andre' R. de la Rocha e-mail address : adlroc@usa.net History: -------- Version 1.0 : 17-Feb-98 First release Version 1.1 : 18-Feb-98 Reading/writing to stdin/stdout under MS-DOS didn't work correctly. Fixed. ---------------------------------------------------------------------------