LHWARP 1.03 A disk tracker for the Amiga Written by Jonathan Forbes What is Lhwarp? (Pronounced L-H-WARP) Lhwarp is a program which will read tracks directly from your floppy disk, compress them, and output them to a file. The advantages of using Lhwarp are: o The disk structure (including boot block) is preserved o Lhwarp Will probably produce a smaller output file than ARC or ZOO o Less hassle than archiving each and every file individually Lhwarp will produce files much smaller than those produced by Warp, due to the fact that Lhwarp uses a more efficient compression algorithm (Adaptive Huffman Encoding); the same algorithm used in Lharc. Typically, an Lhwarp file will be 80% of the size of an equivalent Warp file, resulting in quite reasonable hard drive space savings. Lhwarp's main (and perhaps only) disadvantage is that compression time is very large; it can take from 20 to 25 minutes to compress an entire disk (80 tracks.) There is not too much which can be done about this; you have to pay a price for the extra power. However, this is not as bad as it may seem; a disk only has to be Lhwarp'd once; after Lhwarp'ing, the output file will be transferred over the phone, from BBS to BBS. Because the file will be that much smaller than the equivalent file produced by Warp, the file will take less time to transfer, resulting in a lower phone bill. And, as mentioned before, it will occopy less space on the destination system. More Information Lhwarp output files have the suffix ".LHW". If the filename you give Lhwarp does not end in ".LHW", Lhwarp will append ".LHW" to it. Please leave the suffix alone, and don't change it to ".WRP". The Adaptive Huffman Encoding algorithm was originally coded by Haruyasu Yoshizaki. Lhwarp was compiled and optimised under Lattice C 5.04. Many thanks to Lattice for producing the best C compiler for the Amiga. The algorithms, when compiled under Lattice C 5.04, are almost 10% faster than those in the Amiga version of Lharc, which was compiled under Manx. Parameters To view Lhwarp's parameters, type "Lhwarp"; they are included within the program. You will be presented with: Usage: LHWARP - Drive number (0 for internal, 1 ... 3 for external) - Output|Input filename - Track number (0 ... 79) [valid only in read mode] - Track number (0 ... 79) [valid only in read mode] - Append text in to output file [optional] Examples are: a) Lhwarp read 0 mydisk 0 79 This will read tracks 0 to 79 of the disk in drive 0 (i.e. the entire disk), and will output the result to "mydisk.lhw" b) Lhwarp read 0 mydisk 0 79 mytext This will read tracks 0 to 79 of the disk in drive 0 (i.e. the entire disk), and will output the result to "mydisk.lhw". The text from the file "mytext" will be imported to the output file. Any text stored in the output file will be displayed when the disk is unarchived. c) Lhwarp write 1 mydisk This will output all tracks stored in mydisk.lhw to drive 1. If any text was in the output file, it will be displayed. Virus protection Some people have complained about Warp in that it aids the spread of boot block viruses. It is for this reason that Lhwarp will display the bootblock of any disk it reads or writes, so that one can see what is being Lhwarp'd. Any non-standard looking bootblock should be viewed with suspicion. If you see a non-standard bootblock in read mode, this means that the disk you are reading from might possibly contain a virus. If you see this in write mode, it means that the file you are writing out to your disk may contain a virus. In either case, you should load a virus checker, to make sure (such as VirusX 4.0) Specifications Lhwarp uses ETD_READ and ETD_FORMAT to read/write directly from/to the trackdisk.device. The 16 bytes of label information for each sector are saved in the output file. A 32-bit checksum protects data integrity. Future Possibilities o Support for raw track reads and writes o Other compression algorithms This Program Lhwarp is a freely distributable, copyrighted piece of software. You do not have to pay money to use it, and may upload it wherever you choose, but you are not allowed to sell Lhwarp for profit, or include Lhwarp on a disk which is sold for profit, without the author's (Jonathan Forbes) permission. I can be contacted at 416-927-7844 (voice) or 416-921-6638 (data.) Disclaimer I am in no way responsible for anything this program does; you are using it entirely at your own risk, so if you are kidnapped and held hostage by Libyan terrorists, don't blame me! Lhwarp vs. Warp: File size Lhwarp Warp % Size Diff NewTek Dynamic HAM Disk: 670342 796665 84% 126323