CODEWITHSUNDEEP
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Muralidhar Yaragalla
Muralidhar Yaragalla

Reputation: 427

How download managers work?

Hi from long time i have doubt. when we use "http" protocol to download something the download starts from the first byte of the file. I mean if there is a file of 2MB on the site and when we click it, it starts downloading from the first byte. But when we give the link of the file to the download managers they work differently. I mean after downloading few bytes if we pause they stop downloading and when we resume they start from where they have stopped(not from the beginning). how is this possible?

Upvotes: 0

Views: 884

Answers (2)

Himanshu
Himanshu

Reputation: 363

It really depends on the server where file is hosted if it allows the byte-seeking. In other words, if a file hosting service has "streaming" feature than just "download" feature, applications like download managers will be able to pull a file in pieces & combine them after all the pieces have been downloaded.

Upvotes: 0

Shailendra Pandey
Shailendra Pandey

Reputation: 355

The answer is the server setting. If a server allows the client to read the file from somewhere after the first byte, the client can specify the number of bytes to skip and the server will start sending the file from that position in the file. If the server doesn't allow then the client is forced to start reading the file from the beginning, whether any download manager is used or not. For example 4shared.com always allows to start from beginning. Note: In such cases using any download manager provides no gains.

Upvotes: 1

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