Compress PNG Images on Linux

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PNG images already use DEFLATE data compression algorithm involving a combination of LZ77 and Huffman coding. But the PNG images can be further compressed by removing non-important metadata or using lossy compression to save storage space and/or data transfer bandwidth. In this post, we introduce 2 compression ways with tools available on Linux. Lossless compression
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Blockchain Platforms Introduced, Each in One Sentence

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This post lists some general- and special-purpose blockchains nowadays available with a short description in one sentence. Readers can have a quick understanding of what a blockchain network is built for and what uniqueness that blockchain has. I also give links to beginner friendly resources as learn materials. General purpose blockchains Blockchains for general purpose
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How to limit the network rate used by scp in Linux?

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I am using a shared network and scp to upload files. I do not want to use most of the bandwidth available. How to limit the network rate used by scp in Linux? You can use the -l option of scp to limit the rate of bandwidth. -l limit Limits the used bandwidth, specified in
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Multi-connection multi-part file downloading tools on Linux

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Is there any good multi-connection multi-part file downloading tools on Linux? wget is great but can only make 1 connection for 1 file. Sometimes, it is too slow on some networks. I use aria2 which supportsmMulti-connection download. aria2 can download a file from multiple sources/protocols and tries to utilize your maximum download bandwidth. Really speeds
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How to prevent roommates from hogging bandwidth

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I share a ADSL modem via a Wifi router with several roommates. Sometimes, I find the network bandwidth left is too little. Suspiciously, some one is using BT, Thunder, eMule or other P2P tools. These tools can easily use up all the bandwidth and left little for others. How to prevent some roommates from hogging
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Are there good free CDNs on the Web

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Are there some good free CDNs on the Web? There are some free CDNs in the Web. Cloudflare: https://www.cloudflare.com CloudFlare protects and accelerates any website online. Once your website is a part of the CloudFlare community, its web traffic is routed through our intelligent global network. We automatically optimize the delivery of your web pages
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Improving ssh/scp Performance by Choosing Suitable Ciphers

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Update on Oct. 9, 2014: You should be aware of the possible security problems of blowfish and it is suggested not to be used. Instead, you may consider ChaCha20 as suggested by Tony Arcieri. To use this with OpenSSH, you need to specify the Ciphers in your .ssh/config files as chacha20-poly1305@openssh.com possibly with another default
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Linux UDP Programming Tutorial

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UDP has its advantages over TCP, such as being relatively lightweight and receiving one packet per read call (recvmsg), although the programmers need to handle related issues, such as packet lost and out-of-order packets delivery. This post gives information and references on how to write UDP programs in a C/Linux environment. What is UDP Check
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A Free Personal WordPress Blog Solution

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If you want to have a wordpress blog for FREE co.cc + x10hosting is the best choice. I will introduce both in this post. I will briefly introduce how to set up a wordpress blog like my blog. The overall that I paid for this blog is only $0.89. I can say that it is
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Speeding Up the Site With Apache GZIP Compression

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We can speed up the site with compression while save bandwidth at the same time. As most of the modern browsers support gzip encoding, we can set it up to let the users enjoy faster speed. The Apache mod_deflate is easy to set up and standard. It compress the content on the fly. We can
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Colossus: Successor to the Google File System (GFS)

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Colossus is the successor to the Google File System (GFS) as mentioned in the paper on Spanner at OSDI 2012. Colossus is also used by spanner to store its tablets. The information about Colossus is slim compared with GFS which is published in the paper at SOSP 2003. There is still some information about Colossus
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