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Diffstat (limited to 'usr.bin/compress/doc')
| -rw-r--r-- | usr.bin/compress/doc/NOTES | 139 | ||||
| -rw-r--r-- | usr.bin/compress/doc/README | 283 | ||||
| -rw-r--r-- | usr.bin/compress/doc/revision.log | 116 |
3 files changed, 0 insertions, 538 deletions
diff --git a/usr.bin/compress/doc/NOTES b/usr.bin/compress/doc/NOTES deleted file mode 100644 index 26181bf..0000000 --- a/usr.bin/compress/doc/NOTES +++ /dev/null @@ -1,139 +0,0 @@ -From: James A. Woods <jaw@eos.arc.nasa.gov> - ->From vn Fri Dec 2 18:05:27 1988 -Subject: Re: Looking for C source for RSA -Newsgroups: sci.crypt - -# Illegitimi noncarborundum - -Patents are a tar pit. - -A good case can be made that most are just a license to sue, and nothing -is illegal until a patent is upheld in court. - -For example, if you receive netnews by means other than 'nntp', -these very words are being modulated by 'compress', -a variation on the patented Lempel-Ziv-Welch algorithm. - -Original Ziv-Lempel is patent number 4,464,650, and the more powerful -LZW method is #4,558,302. Yet despite any similarities between 'compress' -and LZW (the public-domain 'compress' code was designed and given to the -world before the ink on the Welch patent was dry), no attorneys from Sperry -(the assignee) have asked you to unplug your Usenet connection. - -Why? I can't speak for them, but it is possible the claims are too broad, -or, just as bad, not broad enough. ('compress' does things not mentioned -in the Welch patent.) Maybe they realize that they can commercialize -LZW better by selling hardware implementations rather than by licensing -software. Again, the LZW software delineated in the patent is *not* -the same as that of 'compress'. - -At any rate, court-tested software patents are a different animal; -corporate patents in a portfolio are usually traded like baseball cards -to shut out small fry rather than actually be defended before -non-technical juries. Perhaps RSA will undergo this test successfully, -although the grant to "exclude others from making, using, or selling" -the invention would then only apply to the U.S. (witness the -Genentech patent of the TPA molecule in the U.S. but struck down -in Great Britain as too broad.) - -The concept is still exotic for those who learned in school the rule of thumb -that one may patent "apparatus" but not an "idea". -Apparently this all changed in Diamond v. Diehr (1981) when the U. S. Supreme -Court reversed itself. - -Scholars should consult the excellent article in the Washington and Lee -Law Review (fall 1984, vol. 41, no. 4) by Anthony and Colwell for a -comprehensive survey of an area which will remain murky for some time. - -Until the dust clears, how you approach ideas which are patented depends -on how paranoid you are of a legal onslaught. Arbitrary? Yes. But -the patent bar the CCPA (Court of Customs and Patent Appeals) -thanks you for any uncertainty as they, at least, stand to gain -from any trouble. - -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= -From: James A. Woods <jaw@eos.arc.nasa.gov> -Subject: Re: Looking for C source for RSA (actually 'compress' patents) - - In article <2042@eos.UUCP> you write: - >The concept is still exotic for those who learned in school the rule of thumb - >that one may patent "apparatus" but not an "idea". - -A rule of thumb that has never been completely valid, as any chemical -engineer can tell you. (Chemical processes were among the earliest patents, -as I recall.) - - ah yes -- i date myself when relaying out-of-date advice from elderly - attorneys who don't even specialize in patents. one other interesting - class of patents include the output of optical lens design programs, - which yield formulae which can then fairly directly can be molded - into glass. although there are restrictions on patenting equations, - the "embedded systems" seem to fly past the legal gauntlets. - - anyway, i'm still learning about intellectual property law after - several conversations from a unisys (nee sperry) lawyer re 'compress'. - - it's more complicated than this, but they're letting (oral - communication only) software versions of 'compress' slide - as far as licensing fees go. this includes 'arc', 'stuffit', - and other commercial wrappers for 'compress'. yet they are - signing up licensees for hardware chips. hewlett-packard - supposedly has an active vlsi project, and unisys has - board-level lzw-based tape controllers. (to build lzw into - a disk controller would be strange, as you'd have to build - in a filesystem too!) - - it's byzantine - that unisys is in a tiff with hp regarding the patents, - after discovering some sort of "compress" button on some - hp terminal product. why? well, professor abraham lempel jumped - from being department chairman of computer science at technion in - israel to sperry (where he got the first patent), but then to work - at hewlett-packard on sabbatical. the second welch patent - is only weakly derivative of the first, so they want chip - licenses and hp relented. however, everyone agrees something - like the current unix implementation is the way to go with - software, so hp (and ucb) long ago asked spencer thomas and i to sign - off on copyright permission (although they didn't need to, it being pd). - lempel, hp, and unisys grumbles they can't make money off the - software since a good free implementation (not the best -- - i have more ideas!) escaped via usenet. (lempel's own pascal - code was apparently horribly slow.) - i don't follow the ibm 'arc' legal bickering; my impression - is that the pc folks are making money off the archiver/wrapper - look/feel of the thing [if ms-dos can be said to have a look and feel]. - - now where is telebit with the compress firmware? in a limbo - netherworld, probably, with sperry still welcoming outfits - to sign patent licenses, a common tactic to bring other small fry - into the fold. the guy who crammed 12-bit compess into the modem - there left. also what is transpiring with 'compress' and sys 5 rel 4? - beats me, but if sperry got a hold of them on these issues, - at&t would likely re-implement another algorithm if they - thought 'compress' infringes. needful to say, i don't think - it does after the abovementioned legal conversation. - my own beliefs on whether algorithms should be patentable at all - change with the weather. if the courts finally nail down - patent protection for algorithms, academic publication in - textbooks will be somewhat at odds with the engineering world, - where the textbook codes will simply be a big tease to get - money into the patent holder coffers... - - oh, if you implement lzw from the patent, you won't get - good rates because it doesn't mention adaptive table reset, - lack thereof being *the* serious deficiency of thomas' first version. - - now i know that patent law generally protects against independent - re-invention (like the 'xor' hash function pleasantly mentioned - in the patent [but not the paper]). - but the upshot is that if anyone ever wanted to sue us, - we're partially covered with - independently-developed twists, plus the fact that some of us work - in a bureacratic morass (as contractor to a public agency in my case). - - quite a mess, huh? i've wanted to tell someone this stuff - for a long time, for posterity if nothing else. - -james - diff --git a/usr.bin/compress/doc/README b/usr.bin/compress/doc/README deleted file mode 100644 index 6803287..0000000 --- a/usr.bin/compress/doc/README +++ /dev/null @@ -1,283 +0,0 @@ - - @(#)README 8.1 (Berkeley) 6/9/93 - -Compress version 4.0 improvements over 3.0: - o compress() speedup (10-50%) by changing division hash to xor - o decompress() speedup (5-10%) - o Memory requirements reduced (3-30%) - o Stack requirements reduced to less than 4kb - o Removed 'Big+Fast' compress code (FBITS) because of compress speedup - o Portability mods for Z8000 and PC/XT (but not zeus 3.2) - o Default to 'quiet' mode - o Unification of 'force' flags - o Manual page overhaul - o Portability enhancement for M_XENIX - o Removed text on #else and #endif - o Added "-V" switch to print version and options - o Added #defines for SIGNED_COMPARE_SLOW - o Added Makefile and "usermem" program - o Removed all floating point computations - o New programs: [deleted] - -The "usermem" script attempts to determine the maximum process size. Some -editing of the script may be necessary (see the comments). [It should work -fine on 4.3 bsd.] If you can't get it to work at all, just create file -"USERMEM" containing the maximum process size in decimal. - -The following preprocessor symbols control the compilation of "compress.c": - - o USERMEM Maximum process memory on the system - o SACREDMEM Amount to reserve for other proceses - o SIGNED_COMPARE_SLOW Unsigned compare instructions are faster - o NO_UCHAR Don't use "unsigned char" types - o BITS Overrules default set by USERMEM-SACREDMEM - o vax Generate inline assembler - o interdata Defines SIGNED_COMPARE_SLOW - o M_XENIX Makes arrays < 65536 bytes each - o pdp11 BITS=12, NO_UCHAR - o z8000 BITS=12 - o pcxt BITS=12 - o BSD4_2 Allow long filenames ( > 14 characters) & - Call setlinebuf(stderr) - -The difference "usermem-sacredmem" determines the maximum BITS that can be -specified with the "-b" flag. - -memory: at least BITS ------- -- ----- ---- - 433,484 16 - 229,600 15 - 127,536 14 - 73,464 13 - 0 12 - -The default is BITS=16. - -The maximum bits can be overrulled by specifying "-DBITS=bits" at -compilation time. - -WARNING: files compressed on a large machine with more bits than allowed by -a version of compress on a smaller machine cannot be decompressed! Use the -"-b12" flag to generate a file on a large machine that can be uncompressed -on a 16-bit machine. - -The output of compress 4.0 is fully compatible with that of compress 3.0. -In other words, the output of compress 4.0 may be fed into uncompress 3.0 or -the output of compress 3.0 may be fed into uncompress 4.0. - -The output of compress 4.0 not compatible with that of -compress 2.0. However, compress 4.0 still accepts the output of -compress 2.0. To generate output that is compatible with compress -2.0, use the undocumented "-C" flag. - - -from mod.sources, submitted by vax135!petsd!joe (Joe Orost), 8/1/85 --------------------------------- - -Enclosed is compress version 3.0 with the following changes: - -1. "Block" compression is performed. After the BITS run out, the - compression ratio is checked every so often. If it is decreasing, - the table is cleared and a new set of substrings are generated. - - This makes the output of compress 3.0 not compatible with that of - compress 2.0. However, compress 3.0 still accepts the output of - compress 2.0. To generate output that is compatible with compress - 2.0, use the undocumented "-C" flag. - -2. A quiet "-q" flag has been added for use by the news system. - -3. The character chaining has been deleted and the program now uses - hashing. This improves the speed of the program, especially - during decompression. Other speed improvements have been made, - such as using putc() instead of fwrite(). - -4. A large table is used on large machines when a relatively small - number of bits is specified. This saves much time when compressing - for a 16-bit machine on a 32-bit virtual machine. Note that the - speed improvement only occurs when the input file is > 30000 - characters, and the -b BITS is less than or equal to the cutoff - described below. - -Most of these changes were made by James A. Woods (ames!jaw). Thank you -James! - -To compile compress: - - cc -O -DUSERMEM=usermem -o compress compress.c - -Where "usermem" is the amount of physical user memory available (in bytes). -If any physical memory is to be reserved for other processes, put in -"-DSACREDMEM sacredmem", where "sacredmem" is the amount to be reserved. - -The difference "usermem-sacredmem" determines the maximum BITS that can be -specified, and the cutoff bits where the large+fast table is used. - -memory: at least BITS cutoff ------- -- ----- ---- ------ - 4,718,592 16 13 - 2,621,440 16 12 - 1,572,864 16 11 - 1,048,576 16 10 - 631,808 16 -- - 329,728 15 -- - 178,176 14 -- - 99,328 13 -- - 0 12 -- - -The default memory size is 750,000 which gives a maximum BITS=16 and no -large+fast table. - -The maximum bits can be overruled by specifying "-DBITS=bits" at -compilation time. - -If your machine doesn't support unsigned characters, define "NO_UCHAR" -when compiling. - -If your machine has "int" as 16-bits, define "SHORT_INT" when compiling. - -After compilation, move "compress" to a standard executable location, such -as /usr/local. Then: - cd /usr/local - ln compress uncompress - ln compress zcat - -On machines that have a fixed stack size (such as Perkin-Elmer), set the -stack to at least 12kb. ("setstack compress 12" on Perkin-Elmer). - -Next, install the manual (compress.l). - cp compress.l /usr/man/manl - cd /usr/man/manl - ln compress.l uncompress.l - ln compress.l zcat.l - - - or - - - cp compress.l /usr/man/man1/compress.1 - cd /usr/man/man1 - ln compress.1 uncompress.1 - ln compress.1 zcat.1 - - regards, - petsd!joe - -Here is a note from the net: - ->From hplabs!pesnta!amd!turtlevax!ken Sat Jan 5 03:35:20 1985 -Path: ames!hplabs!pesnta!amd!turtlevax!ken -From: ken@turtlevax.UUCP (Ken Turkowski) -Newsgroups: net.sources -Subject: Re: Compress release 3.0 : sample Makefile -Organization: CADLINC, Inc. @ Menlo Park, CA - -In the compress 3.0 source recently posted to mod.sources, there is a -#define variable which can be set for optimum performance on a machine -with a large amount of memory. A program (usermem) to calculate the -useable amount of physical user memory is enclosed, as well as a sample -4.2bsd Vax Makefile for compress. - -Here is the README file from the previous version of compress (2.0): - ->Enclosed is compress.c version 2.0 with the following bugs fixed: -> ->1. The packed files produced by compress are different on different -> machines and dependent on the vax sysgen option. -> The bug was in the different byte/bit ordering on the -> various machines. This has been fixed. -> -> This version is NOT compatible with the original vax posting -> unless the '-DCOMPATIBLE' option is specified to the C -> compiler. The original posting has a bug which I fixed, -> causing incompatible files. I recommend you NOT to use this -> option unless you already have a lot of packed files from -> the original posting by thomas. ->2. The exit status is not well defined (on some machines) causing the -> scripts to fail. -> The exit status is now 0,1 or 2 and is documented in -> compress.l. ->3. The function getopt() is not available in all C libraries. -> The function getopt() is no longer referenced by the -> program. ->4. Error status is not being checked on the fwrite() and fflush() calls. -> Fixed. -> ->The following enhancements have been made: -> ->1. Added facilities of "compact" into the compress program. "Pack", -> "Unpack", and "Pcat" are no longer required (no longer supplied). ->2. Installed work around for C compiler bug with "-O". ->3. Added a magic number header (\037\235). Put the bits specified -> in the file. ->4. Added "-f" flag to force overwrite of output file. ->5. Added "-c" flag and "zcat" program. 'ln compress zcat' after you -> compile. ->6. The 'uncompress' script has been deleted; simply -> 'ln compress uncompress' after you compile and it will work. ->7. Removed extra bit masking for machines that support unsigned -> characters. If your machine doesn't support unsigned characters, -> define "NO_UCHAR" when compiling. -> ->Compile "compress.c" with "-O -o compress" flags. Move "compress" to a ->standard executable location, such as /usr/local. Then: -> cd /usr/local -> ln compress uncompress -> ln compress zcat -> ->On machines that have a fixed stack size (such as Perkin-Elmer), set the ->stack to at least 12kb. ("setstack compress 12" on Perkin-Elmer). -> ->Next, install the manual (compress.l). -> cp compress.l /usr/man/manl - or - -> cp compress.l /usr/man/man1/compress.1 -> ->Here is the README that I sent with my first posting: -> ->>Enclosed is a modified version of compress.c, along with scripts to make it ->>run identically to pack(1), unpack(1), an pcat(1). Here is what I ->>(petsd!joe) and a colleague (petsd!peora!srd) did: ->> ->>1. Removed VAX dependencies. ->>2. Changed the struct to separate arrays; saves mucho memory. ->>3. Did comparisons in unsigned, where possible. (Faster on Perkin-Elmer.) ->>4. Sorted the character next chain and changed the search to stop ->>prematurely. This saves a lot on the execution time when compressing. ->> ->>This version is totally compatible with the original version. Even though ->>lint(1) -p has no complaints about compress.c, it won't run on a 16-bit ->>machine, due to the size of the arrays. ->> ->>Here is the README file from the original author: ->> ->>>Well, with all this discussion about file compression (for news batching ->>>in particular) going around, I decided to implement the text compression ->>>algorithm described in the June Computer magazine. The author claimed ->>>blinding speed and good compression ratios. It's certainly faster than ->>>compact (but, then, what wouldn't be), but it's also the same speed as ->>>pack, and gets better compression than both of them. On 350K bytes of ->>>unix-wizards, compact took about 8 minutes of CPU, pack took about 80 ->>>seconds, and compress (herein) also took 80 seconds. But, compact and ->>>pack got about 30% compression, whereas compress got over 50%. So, I ->>>decided I had something, and that others might be interested, too. ->>> ->>>As is probably true of compact and pack (although I haven't checked), ->>>the byte order within a word is probably relevant here, but as long as ->>>you stay on a single machine type, you should be ok. (Can anybody ->>>elucidate on this?) There are a couple of asm's in the code (extv and ->>>insv instructions), so anyone porting it to another machine will have to ->>>deal with this anyway (and could probably make it compatible with Vax ->>>byte order at the same time). Anyway, I've linted the code (both with ->>>and without -p), so it should run elsewhere. Note the longs in the ->>>code, you can take these out if you reduce BITS to <= 15. ->>> ->>>Have fun, and as always, if you make good enhancements, or bug fixes, ->>>I'd like to see them. ->>> ->>>=Spencer (thomas@utah-20, {harpo,hplabs,arizona}!utah-cs!thomas) ->> ->> regards, ->> joe ->> ->>-- ->>Full-Name: Joseph M. Orost ->>UUCP: ..!{decvax,ucbvax,ihnp4}!vax135!petsd!joe ->>US Mail: MS 313; Perkin-Elmer; 106 Apple St; Tinton Falls, NJ 07724 ->>Phone: (201) 870-5844 diff --git a/usr.bin/compress/doc/revision.log b/usr.bin/compress/doc/revision.log deleted file mode 100644 index 16ca49d..0000000 --- a/usr.bin/compress/doc/revision.log +++ /dev/null @@ -1,116 +0,0 @@ -/* - * $Hdr: compress.c,v 4.0 85/07/30 12:50:00 joe Release $ - * $Lg: compress.c,v $ - * Revision 4.0 85/07/30 12:50:00 joe - * Removed ferror() calls in output routine on every output except first. - * Prepared for release to the world. - * - * Revision 3.6 85/07/04 01:22:21 joe - * Remove much wasted storage by overlaying hash table with the tables - * used by decompress: tab_suffix[1<<BITS], stack[8000]. Updated USERMEM - * computations. Fixed dump_tab() DEBUG routine. - * - * Revision 3.5 85/06/30 20:47:21 jaw - * Change hash function to use exclusive-or. Rip out hash cache. These - * speedups render the megamemory version defunct, for now. Make decoder - * stack global. Parts of the RCS trunks 2.7, 2.6, and 2.1 no longer apply. - * - * Revision 3.4 85/06/27 12:00:00 ken - * Get rid of all floating-point calculations by doing all compression ratio - * calculations in fixed point. - * - * Revision 3.3 85/06/24 21:53:24 joe - * Incorporate portability suggestion for M_XENIX. Got rid of text on #else - * and #endif lines. Cleaned up #ifdefs for vax and interdata. - * - * Revision 3.2 85/06/06 21:53:24 jaw - * Incorporate portability suggestions for Z8000, IBM PC/XT from mailing list. - * Default to "quiet" output (no compression statistics). - * - * Revision 3.1 85/05/12 18:56:13 jaw - * Integrate decompress() stack speedups (from early pointer mods by McKie). - * Repair multi-file USERMEM gaffe. Unify 'force' flags to mimic semantics - * of SVR2 'pack'. Streamline block-compress table clear logic. Increase - * output byte count by magic number size. - * - * Revision 3.0 84/11/27 11:50:00 petsd!joe - * Set HSIZE depending on BITS. Set BITS depending on USERMEM. Unrolled - * loops in clear routines. Added "-C" flag for 2.0 compatibility. Used - * unsigned compares on Perkin-Elmer. Fixed foreground check. - * - * Revision 2.7 84/11/16 19:35:39 ames!jaw - * Cache common hash codes based on input statistics; this improves - * performance for low-density raster images. Pass on #ifdef bundle - * from Turkowski. - * - * Revision 2.6 84/11/05 19:18:21 ames!jaw - * Vary size of hash tables to reduce time for small files. - * Tune PDP-11 hash function. - * - * Revision 2.5 84/10/30 20:15:14 ames!jaw - * Junk chaining; replace with the simpler (and, on the VAX, faster) - * double hashing, discussed within. Make block compression standard. - * - * Revision 2.4 84/10/16 11:11:11 ames!jaw - * Introduce adaptive reset for block compression, to boost the rate - * another several percent. (See mailing list notes.) - * - * Revision 2.3 84/09/22 22:00:00 petsd!joe - * Implemented "-B" block compress. Implemented REVERSE sorting of tab_next. - * Bug fix for last bits. Changed fwrite to putchar loop everywhere. - * - * Revision 2.2 84/09/18 14:12:21 ames!jaw - * Fold in news changes, small machine typedef from thomas, - * #ifdef interdata from joe. - * - * Revision 2.1 84/09/10 12:34:56 ames!jaw - * Configured fast table lookup for 32-bit machines. - * This cuts user time in half for b <= FBITS, and is useful for news batching - * from VAX to PDP sites. Also sped up decompress() [fwrite->putc] and - * added signal catcher [plus beef in writeerr()] to delete effluvia. - * - * Revision 2.0 84/08/28 22:00:00 petsd!joe - * Add check for foreground before prompting user. Insert maxbits into - * compressed file. Force file being uncompressed to end with ".Z". - * Added "-c" flag and "zcat". Prepared for release. - * - * Revision 1.10 84/08/24 18:28:00 turtlevax!ken - * Will only compress regular files (no directories), added a magic number - * header (plus an undocumented -n flag to handle old files without headers), - * added -f flag to force overwriting of possibly existing destination file, - * otherwise the user is prompted for a response. Will tack on a .Z to a - * filename if it doesn't have one when decompressing. Will only replace - * file if it was compressed. - * - * Revision 1.9 84/08/16 17:28:00 turtlevax!ken - * Removed scanargs(), getopt(), added .Z extension and unlimited number of - * filenames to compress. Flags may be clustered (-Ddvb12) or separated - * (-D -d -v -b 12), or combination thereof. Modes and other status is - * copied with copystat(). -O bug for 4.2 seems to have disappeared with - * 1.8. - * - * Revision 1.8 84/08/09 23:15:00 joe - * Made it compatible with vax version, installed jim's fixes/enhancements - * - * Revision 1.6 84/08/01 22:08:00 joe - * Sped up algorithm significantly by sorting the compress chain. - * - * Revision 1.5 84/07/13 13:11:00 srd - * Added C version of vax asm routines. Changed structure to arrays to - * save much memory. Do unsigned compares where possible (faster on - * Perkin-Elmer) - * - * Revision 1.4 84/07/05 03:11:11 thomas - * Clean up the code a little and lint it. (Lint complains about all - * the regs used in the asm, but I'm not going to "fix" this.) - * - * Revision 1.3 84/07/05 02:06:54 thomas - * Minor fixes. - * - * Revision 1.2 84/07/05 00:27:27 thomas - * Add variable bit length output. - * - */ - -static char rcs_ident[] = - "$Hdr: compress.c,v 4.0 85/07/30 12:50:00 joe Release $"; |