Get to know Docker in 15 minutes

This post introduces the evolution of Docker, commonly used Docker commands and caveats that a long-time IT pro ran into as a first time Docker user.…

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Cross Compile for Debian Stretch Using sbuild on Ubuntu 18.04

This article describes using sbuild to cross compile Debian packages on a Ubuntu machine. I assume the reverse (though I didn't test) is equally true. sbuild requires Debian Stretch or later, and should work on Debian derived distributions.BackgroundMany systems are based on a Debian distribution that native compilation isn't…

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Merge Multiple Partitions into One Logical Volume on MacOS

This article describes a method to identify bad sectors and isolate them. Then use CoreStorage to merge non-contiguous partitions into one logical volume that appears as a single disk to users and applications in macOS.The ProblemI have a 1TB hard disk. After a couple of years' use, some bad…

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REDIR - Unbound DNS for Adblock

This article introduces REDIR, aka "redirection module", an extension to Unbound DNS that I have developed for very quickly answering queries of blocked domains (ads, trackers, malware sites and etc) and requires little extra resources. For example, a fresh instance of Unbound with REDIR enabled occupies less than six Mbyte…

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USB Speed and Power in One Page

I found USB standards and related buzzwords have evolved into a state beyond my comprehension and memory over the years. Below are notes to myself and will be updated when new information is available or standards updated. If you also find them helpful, perhaps you could let me know.Data…

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User Space Bootstrap in EdgeRouter Firmware 2.0

BackgroundUbiquiti released firmware v2.0.0 for EdgeRouter models at the turn of 2019. FW 2.0 is based on Debian Stretch and has been in development for the past two years or so. Cavium models come with Linux kernel 4.9.y. ERX series come with kernel 4.14.…

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EDNS Client-Subnet

The problemA recursive DNS resolver such as Google Public DNS or your ISP's DNS server resolves domain names into IP addresses. Popular websites or services are usually hosted on Content Delivery Networks (CDN) where a domain name could resolve into different IP corresponding to servers in disperse locations. In such…

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