Re: [platform-update-dev] Parallel downloading

["Jeff Turnham" <turnham@xxxxxxxxxx>]

I am basing this on my use of Download Accelerator Plus.  (can get it from www.download.com).

When downloading a file it opens 4 connections to a server and downloads the file in 4 pieces and then re-assembles locally.
This doesn't sound like it should make much difference, but I see remarkable difference when downloading large files.
One anecdotal example: (650MB WSAD driver takes 1 hr to download...but with DAP it takes 11 minutes).

From the DAP FAQ (at http://www.speedbit.com/FAQ.asp):

3. How does Download Accelerator Plus accelerate the delivery of files?
DAP acceleration is achieved by two factors: locating the most responsive servers from which the file will be downloaded, and by implementing multi-connection downloading from those servers.

• Downloading from the most responsive servers - DAP executes a proximity check to determine which of the available mirror sites are most responsive in relation to the specific user's location. The file is then downloaded from the most responsive server(s).
• Multi-connection downloading - the file is downloaded in several segments through multiple connections and reassembled at the user's PC. This results in better utilization of the user's available bandwidth.

Thanks...

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\
 Jeff Turnham
 WebSphere Tools Release Team
 IBM Toronto Lab, D3-646
 (905) 413-4319
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\

Dejan Glozic/Toronto/IBM@IBMCA Sent by: platform-update-dev-admin@xxxxxxxxxxx 04/15/2003 12:23 PM Please respond to platform-update-dev

To:        platform-update-dev@xxxxxxxxxxx         cc:                 Subject:        [platform-update-dev] Parallel downloading

Thinking a bit more about the recent suggestion (download manager that is
capable of downloading several plug-ins in parallel by opening multiple
connections).

Jeff, are you implying that connecting with one stream and downloading
bytes does not use the connection to its full capacity and that we can tap
into that unused capacity with more connections?

I would be surprised because my experience with downloading three zip files
of a comparable size from using a browser (with three separate download
progress dialog shown) indicates that throughput goes down to roughly one
third (hardly surprising :-). If you add overhead of managing processes, I
cannot see how we can gain anything this way.

Regards,

Dejan Glozic, Ph.D.
Manager, Eclipse Platform Components
D2/MY7/8200/MKM
IBM Canada Ltd.
Tel. 905 413-2745  T/L 969-2745
Fax. 905 413-4854

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