aria2 に似たアプリケーションはいくつか存在しますが、以下の 2 点 において aria2 は差別化されます: (1) 複数のソース (http/ftp そして BitTorrent) からダウンロードで きる。 (2) aria2 に URL のリストを与えた場合、それらを一つ一つ逐次的にダウンロー ドするのではなく、複数並列でダウンロードすることができます。一つ ずつダウンロードを待つ必要はないのです。これにより aria2 は与え られた帯域をめいいっぱい使用して高速なダウンロードを実現します。
ファイルをHTTP(S)/FTPとBitTorrentの両方から同時にダウンロードする機能を持っています。HTTP(S)/FTPからダウンロードしたデータは、BitTorrentネットワークにアップロードされます.
信頼性 という意味でもっともすぐれたHTTP(S)/FTPダウンロードユーティリティ です。なぜなら、Metalink のチャンクチェックサムをサポートしており、 BitTorrentのようにダウンロードした部分部分のチェックサムを照合す る機能をもつからです。チェックサムが違っていればその部分だけダウ ンロードすればよいのです。従来のようなファイルをすべてダウンロード してからチェックサムをとり、間違っていれば全部ダウンロードしなおすことと較べてください。 その差はファイルサイズが大きくなるにつれて明らかです。
This release adds the ability to persist GID across sessions. The GID will be saved with --save-session. There are several restrictions how GID is persisted. See the manual for details. For this change, now GID is 64 bits binary data and represented by 16 characters hex string in RPC query. The disk cache feature was added, which may reduce disk activity. The console readout was redesigned. The warning displayed when --file-allocation=falloc is used on MinGW32 build was removed as a bug.
* mingw32: Re-open files with read-only mode enabled on seeding
On Mingw32 build, if aria2 opens file with GENERIC_WRITE access
right, some programs cannot open the file aria2 is seeding. To avoid
this situation, re-open files with read-only enabled when seeding is
about to begin.
* Save gid option with --save-session option
* Added --gid option
This option sets GID manually. aria2 identifies each download by the
ID called GID. The GID must be hex string of 16 characters, thus
[0-9a-zA-Z] are allowed and leading zeros must not be stripped. The
GID all 0 is reserved and must not be used. The GID must be unique,
otherwise error is reported and the download is not added. This
option is useful when restoring the sessions saved using
--save-session option. If this option is not used, new GID is
generated by aria2.
* Use 64 bits random bytes as GID
This change replaces the current 64 bit sequential GID with 64 bits
random bytes GID in an attempt to support persistent
GID. Internally, the GID is stored as uint64_t. For human
representation and RPC interface, GID is represented as 16 bytes hex
string. For console readout, 16 bytes are too long, so it is
abbreviated to first 6 bytes. When querying GID in RPC calls, user
can speicfy the prefix of GID as long as the prefix is shared by
more than 1 GID entries.
* Fixed BitfieldMan::getOffsetCompletedLength overflow on 32-bit systems
* mingw32: Use HANDLE only for MinGW32 build
* Changed console readout, making it more compact
"SIZE:" is removed because it is obvious. SEEDING, SEED, SPD and UP
are now replaced with SEED, SD, DL and UL respectively.
* Compact readout when more than 1 simultaneous downloads are going on
If more than 1 simultaneous downloads are going on, use more compact
format in readout. Currently, at most 5 download stats are
displayed.
util::abbrevSize() is rewritten to support "Gi" unit and provides
more compact abbreviation.
* Console color output
Log level and download result string is now colored.
* Logger: Simplified console output and change level format in log
The date and time are now removed from console output. The log
level is now formatted as "[LEVEL]".
* Start to find faster host before the number of missing segments becomes 1
The old implementation starts to find faster host when the number of
missing segment becomes 1. Because of --min-split-size option,
before the number of missing segment becomes 1, the number of
connection becomes 1 and it can be slow. In this case, we have to
wait until the last segment is reached. The new implementation
starts to find faster host when the remaining length is less than
--min-split-size * 2, to mitigate the problem stated above.
* Removed warning when --file-allocation=falloc is used in MinGW32 build
The warning was just a mistake. SetFilePointerEx + SetEndOfFile
actually allocate disk space.
* Write data in 4K aligned offset in write with disk cache enabled
This greatly reduces disk activity especially on Win + NTFS. Not so
much difference on Linux.
* mingw32: Removed FSCTL_SET_SPARSE set
* Added --disk-cache option
This option enables disk cache. If SIZE is 0, the disk cache is
disabled. This feature caches the downloaded data in memory, which
grows to at most SIZE bytes. The cache storage is created for aria2
instance and shared by all downloads. The one advantage of the disk
cache is reduce the disk seek time because the data is written in
larger unit and it is reordered by the offset of the file. If the
underlying file is heavily fragmented it is not the case.
