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 specify the output filenames in BitTorrent downloads and the option to limit overall download speed and dry run mode which just checks the availability of the remote file. -i list option can now take new options: select-file and index-out. The default behavior of sending HTTP Authorization header is reverted back to version 1.1.2 style. The bug in AdaptiveURISelector was fixed. You can now seed read-only files in BitTorrent. --file-allocation option can take new parameter 'falloc'. If it is given and you are using newer file systems such as ext4, btrfs or xfs, large(few GiB) files are allocated almost instantly. The performance optimization has been done and aria2 runs more efficiently.
Indonesian, Russian, Italian, Ukrainian, Simplified Chinese, Japanese, Spanish and Norwegian Nynorsk translations were updated.
* Added 'falloc' parameter for --file-allocation option. 'falloc'
allocation mode uses posix_fallocate() system call to allocate file
on disk. If you are using newer file systems such as ext4 (with
extents support), btrfs or xfs, 'falloc' is your best choice. It
allocates large(few GiB) files almost instantly. Don't use 'falloc'
with legacy file systems such as ext3 because it takes almost same
time as 'prealloc' and it blocks aria2 entirely until allocation
finishes. 'falloc' may not be available if your system doesn't have
posix_fallocate() system call.
* Added --bt-tracker-interval option to specify the interval between
tracker requests. If non-zero value is specified, aria2 uses it and
ignores the interval value in the response of tracker. If zero is
specified, aria2 determines the inteval value based on the tarcker
response and download progress.
* Reduced CPU usage in RarestPieceSelector.
* Reduced CPU usage when hitting download limit/upload limit.
* Changed the default value of --uri-selector option from 'inorder' to
'feedback'
* Included current URI in exception message.
* Fixed the bug that AdaptiveURISelector doesn't select any URI when
all URIs are tested and their timeout is not reached.
* Reuse URIs when all unused URIs run out.
* Removed --direct-file-mapping option and CopyDiskAdaptor.
* Added --dry-run option. In this mode, aria2 just checks whether
the remote file is available and doesn't download data. This
option has effect on HTTP/FTP downloads and BitTorrent downloads
are canceled in this mode.
* Parse options in -i list using OptionParser.
* Don't reset URI in retry to avoid additional round trips because
of redirects.
* Added --index-out option to specify each file path for torrent. The
index shown in --show-files option is used to specify which file
path should be altered. For example, to change the file path with
index=2, use --index-out=2=aria2.tar.bz2. You can use this option
multiple times: --index-out=1=aria2.tar.bz2
--index-out=2=aria2-opt.tar.bz2. The short hand form -O is also
available. This option can be specified in -i list.
* Added --max-overall-download-limit option. Now --max-upload-limit
option is not ignored when --max-overall-upload-limit option has
non-zero value. aria2 checks download(upload) speed in the order:
first checks overall speed limit and if it is not exceeded, then
checks speed limit per download. Thus you can specify both
value. For example, set --max-overall-download-limit=1M and
--max-download-limit=500K to prevent from one download from eating
all overall speed limit.
* Now select-file can be specified in the uri list(-i list).
* Made the upper value of --max-concurrent-downloads options unlimited.
* Fixed the bug that disk writer is not created even if it shares same
piece with the preceding file if the length of previous file is 0.
* In BitTorrent, Open files in read-only mode for hash check. After
that, re-open file in read/write mode only when the download is
not finished.
* Added --http-auth-challenge option. If it is set to true, aria2
sends HTTP authorization header only when it is requested by the
server. If false is set, then authorization header is always sent to
the server. This is useful for servers that don't respond 401 code
when authentication is required. There is an exception: if username
and password are embedded in URI, authorization header is always
sent to the server regardless of this option. The default value of
this option is false.
