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   RAR      RAR compressor program discussion      63 messages   

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   Message 2 of 63   
   Janis Kracht to All   
   2 What's New in Rar V5.61   
   28 Nov 18 01:12:28   
   
   AREA:RAR   
   ld of archiving dialog.   
      
      6. Switch -ai can be used when creating RAR archive,   
         so predefined values, typical for file and folder,   
         are stored instead of actual attributes.   
         Previously this switch could be used only when extracting.   
      
      
      Version 5.01   
      
      1. RAR 5.0 archives can include an optional quick open information   
         controlled with -qo[-|+] switch or "Quick open information" options   
         group in archiving dialog. It allows to open the archive contents   
         in WinRAR faster.   
      
         This version provides better update performance for archives   
         containing both quick open information and service records,   
         such as NTFS file security. Also default parameters of quick open   
         information are optimized to achieve faster open time for such archives.   
      
      2. Bugs fixed:   
      
         a) "Find" command could fail when searching text string in .7z archives;   
      
         b) when opening RAR 5.0 archive with encrypted file names stored   
            in another such archive, WinRAR could issue an erroneous message   
            that password is incorrect. It happened only if passwords to inner   
            and outer archives were different. It did not affect extraction,   
            all files could be unpacked regardless of this message;   
      
         c) option "Use for all archives" in password dialog did not suppress   
            additional password requests for RAR 5.0 archives with encrypted   
            file names;   
      
         d) WinRAR address bar did not process correctly environment variable   
            based paths, such as %temp%;   
      
         e) storing NTFS file security and alternate data streams did not work   
            for file pathnames longer than 260 characters;   
      
         f) "Test" command could erroneously report damaged data in valid   
            recovery record if only a part of files in RAR 5.0 archive   
            was tested. It did not happen if entire archive contents was tested;   
      
         g) "Test" command erroneously reported errors when verifying   
            RAR 4.x Unix symbolic links;   
      
         h) WinRAR "View" command did not work for files inside of BZIP2 archives;   
      
         i) if "High precision modification time" option in archiving dialog   
            was turned off, WinRAR did not store the modification time at all   
            instead of storing a lower precision time;   
      
         j) destination paths containing .\ or ..\ component did not work   
            when extracting non-RAR archives in WinRAR command line mode;   
      
         k) WinRAR failed to unpack multivolume CAB archives.   
      
      
      Version 5.00   
      
      1. New RAR 5.0 archiving format. You can use "RAR 5.0" option   
         in archiving dialog or -ma command line switch to create   
         RAR 5.0 archives.   
      
         Older software including older WinRAR versions is not able to   
         decompress RAR 5.0 archives, so if you plan to send an archive   
         to other people, it is necessary to take the compatibility issue   
         into consideration. You can select "RAR" instead of "RAR5" option   
         in archiving dialog to create RAR 4.x archives compatible with   
         previous WinRAR versions.   
      
      2. Changes in RAR 5.0 compression algorithm:   
      
         a) maximum compression dictionary size is increased up to 1 GB   
            in 64 bit WinRAR. 32 bit WinRAR version can use up to 256 MB   
            dictionary when creating an archive. Both 32 bit and 64 bit   
            versions can unpack archives with any dictionary size,   
            including 1 GB;   
      
         b) default dictionary size for RAR 5.0 is 32 MB, typically resulting   
            in higher compression ratio and lower speed than RAR 4.x 4 MB.   
            You can use "Dictionary size" archiving dialog option or -md   
            switch to change this value;   
      
         c) -md switch syntax is modified to support larger dictionary   
            sizes. Append 'k', 'm' and 'g' modifiers to specify the size   
            in kilo-, mega- and gigabytes, like -md64m for 64 MB dictionary.   
            If modifiers are not present, megabytes are assumed,   
            so -md64m is equal to -md64;   
      
         d) RAR 5.0 format includes Intel IA-32 executable and delta   
            compression algorithms, but RAR 4.x text, audio, true color   
            and Itanium algorithms are not supported. These excluded algorithms   
            are not efficient for modern data types and hardware configurations;   
      
         e) RAR 5.0 decompression can utilize several CPU cores.   
            Though not to same extent as in compression algorithm,   
            it improves the decompression speed on large files   
            with poorly compressible data or when using BLAKE2 checksums.   
      
      3. Changes in RAR 5.0 archive format:   
      
         a) file times are stored as Coordinated Universal Time (UTC)   
            instead of former local time, making file exchange among   
            several time zones more straightforward;   
      
         b) file names and archive comments use UTF-8 encoding.   
      
      4. RAR 5.0 recovery record is based on Reed-Solomon error correction   
         codes. If recovery record size is large enough, 5% and more,   
         the new error correction scheme provides much higher resistance to   
         multiple damages comparing to RAR 4.x recovery record.   
         Smaller record, such as 1 - 2%, or less random damage type would   
         result in less difference between 4.x and 5.0. For single continuous   
         damage 4.x and 5.0 efficiency is about the same.   
      
         Additionally to usual data erasures, the new recovery record   
         is able to detect deletions and insertions of much larger size   
         than in previous RAR versions. Maximum insertion size is several   
         megabytes. Maximum deletion size depends on the damage type   
         and in some cases can be as large as the recovery record size.   
      
         Still, the best recovery performance and efficiency is achieved   
         if no deletions and insertions are present, so all data including   
         damaged sectors preserve their original positions. Thus, if you use   
         some special software to copy an archive from damaged media,   
         it is better to choose the mode, when damaged sectors are filled by   
         zeroes or any other data instead of cutting them out completely   
         from resulting file.   
      
         RAR 5.0 recovery record is more resistant to damage of recovery record   
         itself and can utilize a partially corrupt recovery record data.   
         Note, though, that "Repair" command does not fix broken blocks   
         in recovery record. Only file data are corrected. After successful   
         archive repair, you may need to create a new recovery record   
         for saved files.   
      
         New recovery record is not based on 512 byte sectors anymore   
         and incorporates more complicated data structures. So it is impossible   
         to specify its size in sectors. For RAR 5.0 archives the parameter of   
         -rr[N] switch and rr[N] command is always treated as a percent of   
         archive size regardless of presence of % character. Typically N%   
         recovery record can repair up to N% of continuously damaged data   
         and increases the archive size by only slightly more than N%.   
         Ability to fix multiple damages is proportional to N.   
      
         We used "Screaming Fast Galois Field Arithmetic Using Intel   
         SIMD Instructions" paper by James S. Plank, Kevin M. Greenan   
         and Ethan L. Miller to improve Reed-Solomon coding performance.   
         Also we are grateful to Artem Drobanov and Bulat Ziganshin   
         for samples and ideas allowed to make Reed-Solomon coding   
         more efficient.   
      
      5. "Test" command verifies validity of RAR 5.0 recovery record.   
         Recovery record is tested after processing all archived files.   
      
         If corrupt archive contains the recovery record, it might be possible   
         to repair it even if recovery record validity test is failed.   
         "Repair" command attempts to utilize even a partially damaged   
         recovery record. So treat the negative recovery record test result   
         as a reason to re-create the archive if original files are still   
         available, but not as a reason to avoid "Repair" command.   
      
      6. Changes in RAR 5.0 encryption algorithm:   
      
         a) encryption algorithm is changed from AES-128 to AES-256 in CBC mode.   
            Key derivation function is based on PBKDF2 using HMAC-SHA256;   
      
         b) special password verification value allows to detect most of   
            wrong passwords without necessity to unpack the entire file;   
      
         c) if archive headers are not encrypted ("Encrypt file names" option   
            is off), file checksums for encrypted RAR 5.0 files are modified   
            using a special password dependent algorithm, to make impossible   
            guessing file contents based on checksums. Do not expect such   
            encrypted file checksums to match usual CRC32 and BLAKE2 values.   
      
      7. RAR 5.0 archives allow to utilize 256 bit length BLAKE2sp hash   
         ( https://blake2.net ) instead of 32 bit CRC32 as a file checksum.   
         Enable "Use BLAKE2 file checksum" option in "Options" page of   
         archiving dialog or specify -htb command line switch to use BLAKE2   
         checksums.   
      
         While producing slightly larger archives, BLAKE2 can be used   
         for file contents identification. If two files have the same   
         BLAKE2 value, it practically guarantees that file contents   
         is the same. BLAKE2 error detection property is also stronger   
         than in much shorter CRC32.   
      
      8. Features removed:   
      
         a) authenticity verification feature did not provide the required   
            level of reliability and was removed;   
      
         b) switch -en (do not add "end of archive" block) is not supported   
            by RAR 5.0 archives, which always have the end of archive block.   
            This block helps WinRAR to safely skip external data like   
            digital signatures appended to archive;   
      
         c) old style extension based arcname.rNN volume names are not   
            supported by RAR 5.0 archives, which use only arcname.partN.rar   
            volume names;   
      
         d) file comments are not supported anymore both in RAR 4.x   
            and RAR 5.0 archives. Console RAR 'cf' command is removed.   
            It does not affect the archive comment support, which is present   
            in both versions of archive format and is not planned for removal.   
      
      9. "Set password" command and "Dictionary size" option are moved to   
         "General" page of archiving dialog.   
      
     10. You can use "Save symbolic links as links" option on "Advanced" page   
         of archiving dialog to save and restore NTFS symbolic links   
         and reparse points as links, so their contents is not archived.   
         Command line equivalent of this option is -ol switch.   
      
         Similar option for NTFS hard links is "Save hard links as links".   
         Its command line equivalent is -oh switch.   
      
         Both options are available only for RAR 5.0 archive format.   
      
     11. Added extraction only support for XZ archive format.   
      
     12. Changes in recovery volume processing in RAR 5.0 archive format:   
      
         a) maximum number of RAR+REV volumes in RAR 5.0 format is 65535   
            instead of 255;   
      
         b) recovery volume operations are faster than in RAR 4.x;   
      
         c) additionally to recovery data, RAR 5.0 REV files also store   
            service information such as checksums of protected RAR files.   
            So they are slightly larger than RAR volumes which they protect.   
            If you plan to copy individual RAR and REV files to some removable   
            media, you need to take it into account and specify RAR volume   
            size by a few kilobytes smaller than media size.   
      
     13. Maximum path length for files in RAR and ZIP archives is increased   
         up to 2048 characters.   
      
     14. Command line RAR returns the exit code 11 if it can detect that   
         user entered a wrong password. This code can be returned only   
         for RAR 5.0 archives. It is impossible to distinguish a wrong   
         password and data damage for RAR 4.x archives.   
      
     15. 'v' and 'l' commands display archived file names in the end of line,   
         not in that beginning as before. Also some fields previously   
         available in 'l' and 'v' output are now shown only by 'lt' and 'vt'.   
      
         'vt' and 'lt' commands provide the detailed multiline information   
         for every archived file.   
      
         'vta' and 'lta' also include service headers into list.   
      
      16. Now the default charset for filelists in commands like   
          'rar a arcname @filelist' is ANSI for both WinRAR and console RAR.   
          In previous versions it was ANSI for WinRAR and OEM for console RAR.   
          You can use -scl switch to override this default.   
      
      17. Internal WinRAR viewer can detect and display files in UTF-8   
          and UTF-16 little endian encodings.   
      
      18. UTF-16 little endian encoding is used in RAR and WinRAR log file   
          rar.log, so Unicode file names are stored in the log correctly.   
          WinRAR automatically truncates the old rar.log file in non-Unicode   
          format to avoid mixing different encoding in the same log file.   
          In case of console RAR you need to delete the old rar.log manually,   
          otherwide RAR will append UTF-16 messages to existing rar.log.   
      
   --- BBBS/Li6 v4.10 Toy-3   
    * Origin: Prism bbs (1:261/38)   
   ernate data streams did not work   
            for file pathnames longer than 260 characters;   
      
         f) "Test" command could erroneously report damaged data in valid   
            recovery record if only a part of files in RAR 5.0 archive   
            was tested. It did not happen if entire archive contents was tested;   
      
         g) "Test" command erroneously reported errors when verifying   
            RAR 4.x Unix symbolic links;   
      
         h) WinRAR "View" command did not work for files inside of BZIP2 archives;   
      
         i) if "High precision modification time" option in archiving dialog   
            was turned off, WinRAR did not store the modification time at all   
            instead of storing a lower precision time;   
      
         j) destination paths containing .\ or ..\ component did not work   
            when extracting non-RAR archives in WinRAR command line mode;   
      
         k) WinRAR failed to unpack multivolume CAB archives.   
      
      
      Version 5.00   
      
      1. New RAR 5.0 archiving format. You can use "RAR 5.0" option   
         in archiving dialog or -ma command line switch to create   
         RAR 5.0 archives.   
      
         Older software including older WinRAR versions is not able to   
         decompress RAR 5.0 archives, so if you plan to send an archive   
         to other people, it is necessary to take the compatibility issue   
         into consideration. You can select "RAR" instead of "RAR5" option   
         in archiving dialog to create RAR 4.x archives compatible with   
         previous WinRAR versions.   
      
      2. Changes in RAR 5.0 compression algorithm:   
      
         a) maximum compression dictionary size is increased up to 1 GB   
            in 64 bit WinRAR. 32 bit WinRAR version can use up to 256 MB   
            dictionary when creating an archive. Both 32 bit and 64 bit   
            versions can unpack archives with any dictionary size,   
            including 1 GB;   
      
         b) default dictionary size for RAR 5.0 is 32 MB, typically resulting   
            in higher compression ratio and lower speed than RAR 4.x 4 MB.   
            You can use "Dictionary size" archiving dialog option or -md   
            switch to change this value;   
      
         c) -md switch syntax is modified to support larger dictionary   
            sizes. Append 'k', 'm' and 'g' modifiers to specify the size   
            in kilo-, mega- and gigabytes, like -md64m for 64 MB dictionary.   
            If modifiers are not present, megabytes are assumed,   
            so -md64m is equal to -md64;   
      
         d) RAR 5.0 format includes Intel IA-32 executable and delta   
            compression algorithms, but RAR 4.x text, audio, true color   
            and Itanium algorithms are not supported. These excluded algorithms   
            are not efficient for modern data types and hardware configurations;   
      
         e) RAR 5.0 decompression can utilize several CPU cores.   
            Though not to same extent as in compression algorithm,   
            it improves the decompression speed on large files   
            with poorly compressible data or when using BLAKE2 checksums.   
      
      3. Changes in RAR 5.0 archive format:   
      
         a) file times are stored as Coordinated Universal Time (UTC)   
            instead of former local time, making file exchange among   
            several time zones more straightforward;   
      
         b) file names and archive comments use UTF-8 encoding.   
      
      4. RAR 5.0 recovery record is based on Reed-Solomon error correction   
         codes. If recovery record size is large enough, 5% and more,   
         the new error correction scheme provides much higher resistance to   
         multiple damages comparing to RAR 4.x recovery record.   
         Smaller record, such as 1 - 2%, or less random damage type would   
         result in less difference between 4.x and 5.0. For single continuous   
         damage 4.x and 5.0 efficiency is about the same.   
      
         Additionally to usual data erasures, the new recovery record   
         is able to detect deletions and insertions of much larger size   
         than in previous RAR versions. Maximum insertion size is several   
         megabytes. Maximum deletion size depends on the damage type   
         and in some cases can be as large as the recovery record size.   
      
         Still, the best recovery performance and efficiency is achieved   
         if no deletions and insertions are present, so all data including   
         damaged sectors preserve their original positions. Thus, if you use   
         some special software to copy an archive from damaged media,   
         it is better to choose the mode, when damaged sectors are filled by   
         zeroes or any other data instead of cutting them out completely   
         from resulting file.   
      
         RAR 5.0 recovery record is more resistant to damage of recovery record   
         itself and can utilize a partially corrupt recovery record data.   
         Note, though, that "Repair" command does not fix broken blocks   
         in recovery record. Only file data are corrected. After successful   
         archive repair, you may need to create a new recovery record   
         for saved files.   
      
         New recovery record is not based on 512 byte sectors anymore   
         and incorporates more complicated data structures. So it is impossible   
         to specify its size in sectors. For RAR 5.0 archives the parameter of   
         -rr[N] switch and rr[N] command is always treated as a percent of   
         archive size regardless of presence of % character. Typically N%   
         recovery record can repair up to N% of continuously damaged data   
         and increases the archive size by only slightly more than N%.   
         Ability to fix multiple damages is proportional to N.   
      
         We used "Screaming Fast Galois Field Arithmetic Using Intel   
         SIMD Instructions" paper by James S. Plank, Kevin M. Greenan   
         and Ethan L. Miller to improve Reed-Solomon coding performance.   
         Also we are grateful to Artem Drobanov and Bulat Ziganshin   
         for samples and ideas allowed to make Reed-Solomon coding   
         more efficient.   
      
      5. "Test" command verifies validity of RAR 5.0 recovery record.   
         Recovery record is tested after processing all archived files.   
      
         If corrupt archive contains the recovery record, it might be possible   
         to repair it even if recovery record validity test is failed.   
         "Repair" command attempts to utilize even a partially damaged   
         recovery record. So treat the negative recovery record test result   
         as a reason to re-create the archive if original files are still   
         available, but not as a reason to avoid "Repair" command.   
      
      6. Changes in RAR 5.0 encryption algorithm:   
      
         a) encryption algorithm is changed from AES-128 to AES-256 in CBC mode.   
            Key derivation function is based on PBKDF2 using HMAC-SHA256;   
      
         b) special password verification value allows to detect most of   
            wrong passwords without necessity to unpack the entire file;   
      
         c) if archive headers are not encrypted ("Encrypt file names" option   
            is off), file checksums for encrypted RAR 5.0 files are modified   
            using a special password dependent algorithm, to make impossible   
            guessing file contents based on checksums. Do not expect such   
            encrypted file checksums to match usual CRC32 and BLAKE2 values.   
      
      7. RAR 5.0 archives allow to utilize 256 bit length BLAKE2sp hash   
         ( https://blake2.net ) instead of 32 bit CRC32 as a file checksum.   
         Enable "Use BLAKE2 file checksum" option in "Options" page of   
         archiving dialog or specify -htb command line switch to use BLAKE2   
         checksums.   
      
         While producing slightly larger archives, BLAKE2 can be used   
         for file contents identification. If two files have the same   
         BLAKE2 value, it practically guarantees that file contents   
         is the same. BLAKE2 error detection property is also stronger   
         than in much shorter CRC32.   
      
      8. Features removed:   
      
         a) authenticity verification feature did not provide the required   
            level of reliability and was removed;   
      
         b) switch -en (do not add "end of archive" block) is not supported   
            by RAR 5.0 archives, which always have the end of archive block.   
            This block helps WinRAR to safely skip external data like   
            digital signatures appended to archive;   
      
         c) old style extension based arcname.rNN volume names are not   
            supported by RAR 5.0 archives, which use only arcname.partN.rar   
            volume names;   
      
         d) file comments are not supported anymore both in RAR 4.x   
            and RAR 5.0 archives. Console RAR 'cf' command is removed.   
            It does not affect the archive comment support, which is present   
            in both versions of archive format and is not planned for removal.   
      
      9. "Set password" command and "Dictionary size" option are moved to   
         "General" page of archiving dialog.   
      
     10. You can use "Save symbolic links as links" option on "Advanced" page   
         of archiving dialog to save and restore NTFS symbolic links   
         and reparse points as links, so their contents is not archived.   
         Command line equivalent of this option is -ol switch.   
      
         Similar option for NTFS hard links is "Save hard links as links".   
         Its command line equivalent is -oh switch.   
      
         Both options are available only for RAR 5.0 archive format.   
      
     11. Added extraction only support for XZ archive format.   
      
     12. Changes in recovery volume processing in RAR 5.0 archive format:   
      
         a) maximum number of RAR+REV volumes in RAR 5.0 format is 65535   
            instead of 255;   
      
         b) recovery volume operations are faster than in RAR 4.x;   
      
         c) additionally to recovery data, RAR 5.0 REV files also store   
            service information such as checksums of protected RAR files.   
            So they are slightly larger than RAR volumes which they protect.   
            If you plan to copy individual RAR and REV files to some removable   
            media, you need to take it into account and specify RAR volume   
            size by a few kilobytes smaller than media size.   
      
     13. Maximum path length for files in RAR and ZIP archives is increased   
         up to 2048 characters.   
      
     14. Command line RAR returns the exit code 11 if it can detect that   
         user entered a wrong password. This code can be returned only   
         for RAR 5.0 archives. It is impossible to distinguish a wrong   
         password and data damage for RAR 4.x archives.   
      
     15. 'v' and 'l' commands display archived file names in the end of line,   
         not in that beginning as before. Also some fields previously   
         available in 'l' and 'v' output are now shown only by 'lt' and 'vt'.   
      
         'vt' and 'lt' commands provide the detailed multiline information   
         for every archived file.   
      
         'vta' and 'lta' also include service headers into list.   
      
      16. Now the default charset for filelists in commands like   
          'rar a arcname @filelist' is ANSI for both WinRAR and console RAR.   
          In previous versions it was ANSI for WinRAR and OEM for console RAR.   
          You can use -scl switch to override this default.   
      
      17. Internal WinRAR viewer can detect and display files in UTF-8   
          and UTF-16 little endian encodings.   
      
      18. UTF-16 little endian encoding is used in RAR and WinRAR log file   
          rar.log, so Unicode file names are stored in the log correctly.   
          WinRAR automatically truncates the old rar.log file in non-Unicode   
          format to avoid mixing different encoding in the same log file.   
          In case of console RAR you need to delete the old rar.log manually,   
          otherwide RAR will append UTF-16 messages to existing rar.log.   
      
   --- BBBS/Li6 v4.10 Toy-3   
    * Origin: Prism bbs (1:261/38)   

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