tes@whuts.UUCP (04/14/87)
In article <206900012@mirror>, jvc@mirror.UUCP writes: > > /* Written 12:29 pm Apr 9, 1987 by japplega@csm9a.UUCP */ > >As to PKARC, I am currently discouraging the use of PKARC to archive files > >until it is modified to use another extension. PKARC archives are NOT > >compatible with ARC 5.12 or 5.20!!! After running the performance tests reported last week, (Summary, PKarc was 5 times faster but incompatible in "native" mode, but had a SEAarc compatible mode as fast) I applied the official PKware patch to force PKarc to be totally compatible. I have not had the time for a major test, but I have been (noticably) burnt yet. So.... Without any warrentees, including whether this patch really did come from PKware as I believe, or that it really works as I believe. (Run your own tests). Here is the "PKware DISSQASH.PAT patch file" source. ================================================================ DISSQASH.PAT ================================================================ By default, PKARC 2.0 will "squash" a file if this compression technique would appear to be optimal for that file. While I personally do not think it is desirable to change this, this patch is presented at the request of others who disagree. However, PLEASE DO NOT distribute PKARC 2.0 if it has been patched as shown in this document. Not only can this create problems for recipients of the program that are not aware that the program has been patched, but it is also in strict violation of the license agreement in PKARC to distribute the program in modified form. PKWARE INCORPORATED RESERVES THE RIGHT TO FIND ANYONE WHO DISTRIBUTES PKARC IN MODIFIED FORM WITHOUT EXPRESS WRITTEN CONSENT FROM PKWARE INCORPORATED TO BE IN VIOLATION OF THE SOFTWARE LICENSE AGREEMENT AND LIABLE FOR DAMAGES. Using DEBUG, change the byte at offset F25 hex in the file PKARC.COM, version 2.0, dated 12-15-86. The value in the distribution copy is 75 hex. Changing this value will yield the results shown: Byte at F25 Program Behavior ------------ ---------------- 75 This is the 'normal' value. Squashing will be performed by default, when it is optimal. 74 Reverses the meaning of the "/oc" flag. By default squashing will NOT be performed. Specifying "/oc" on the command line will ENABLE squashing when it is optimal. EB Permanently disables squashing. Squashing will never be performed, regardless if the "/oc" flag is specified or not. WARNING: Changing the value of this byte to any other value will cause unpredicatble program operation. The following example session with debug will change the value to 74. Enter debug pkarc.com<CR> where <CR> means the enter key. Debug will display a "-" prompt. Then enter ef25<CR>. Debug will display something like "xxxx:0F25 75.". The xxxx value will vary from computer to computer. Debug should display the number 75 as above. If this value is not 75, then you do not have PKARC 2.0 and should not continue. Enter 74<CR> followed by w<CR> and then q<CR>. The result should appear similar to: A>debug pkarc.com -ef25 xxxx:0F25 75.74 -w Writing 4430 bytes -q A> -Phil Kat -- ----- Terry Sterkel -====---- AT&T Bell Laboratories --------- {clyde|harvard|cbosgd|allegra|ulysses|ihnp4}!whuts!tes ----- [opinions are obviously only my own]