Notes for ARC 5.21                                        June 6, 1988 This program is based on the MSDOS ARC program, version 5.21, plusa few enhancements...   o ARC also performs Huffman Squeezing on data. The Huffman Squeeze   algorithm was removed from MSDOS ARC after version 5.12. It turns   out to be more efficient than Lempel-Ziv style compression when   compressing graphic images. Squeeze analysis is always done now,   and the best of packing, squeezing, or crunching is used.  o Compresses and extracts Squashed files. "Squashing" was created   by Phil Katz in his PKxxx series of ARC utility programs for   MSDOS. Dan Lanciani wrote the original modifications to ARC's   Crunch code to handle Squashing. I've made minor changes since   then, mostly to reduce the amount of memory required. The 'q'   option flag must be specified to Squash files. The Squashing   algorithm will be used instead of the usual Crunch algorithm,   and will be compared against packing and squeezing, as before. System specific notes:    On MTS, an additional option flag, 'i' for "image mode," wasused. ARC assumes files are text, by default, and will translateMTS files from EBCDIC to ASCII before storing in an archive, andtranslates from ASCII to EBCDIC upon extraction. Specifying the'i' flag will inhibit this translation. This would most commonlybe used when shipping binary images such as TeX DVI files, other.ARC files stored within an archive, etc... The 'r' (run) commandis omitted. It just doesn't seem very useful. Also, ARC cannotrestore MTS files with their original time stamps. (Maybe in afuture release...)    On Unix(tm) systems, the 'i' flag is also present. Unix ARCassumes a binary file, by default. Here the only translationinvolved is in end-of-line processing. When storing text files, ARC willchange '\n' to '\r\n', and does the opposite when extracting files.Carriage returns in any other location are preserved when extracting.This translation only occurs if the 'i' flag is given.   On the Atari ST, the 'h' (for "hold screen") option is present,which simply delays exiting the program. This is typically used whenexecuting ARC from the desktop, to allow reading all of ARC's outputbefore the screen is cleared and the desktop is redrawn. The programwill prompt and wait for a keypress before exiting. Note that sincethere are no "options" for the MARC program, the "hold screen" optionis always active for MARC.    On both Unix and Atari systems, ARC & MARC will search for anenvironment variable named "ARCTEMP" or "TMPDIR." If present, anytemporary files will be created in the specified directory. This isprobably insignificant for Unix users, but can be handy on the Atari,in combination with a RAMdisk. Highly recommended for floppy users.(Unfortunately, you can only take advantage of this when running someform of command shell that allows setting environment variables. Thus,you won't see any speed gains when running from the desktop.)  That about covers things. The enclosed documentation is taken directlyfrom the MSDOS distribution of ARC. Unless specified differently here,the programs behave indentically. Note that ARC521.DOC is identical toARC520.DOC - the differences between the two versions are described inthe file CHANGES.521. Oh yeah - this program may be distributed freely so long as you don'tmodify it in any way. You may not charge for distributing it. (Don'tfeel bad, I can't charge for it either. }-) It'd be nice if you keptthis and the other enclosed doc files with it when distributing, butI'm not going to make a fuss about it. Most people are so familiarwith the program by now that it wouldn't matter much anyway. Youshould keep this README file around, so bug reports & such will findtheir way back to me. (Bugs? What bugs? Nah, there aren't any bugs...)          /                 Howard Chu   ___  /_ , ,_.     University of Michigan       / /(_/(__     hyc@umix.cc.umich.edu           /                umix!hyc          '