It is common for programs to write to files in filesystems on disks. However, what if the disk was almost full when your program writes to the filesystem on a disk? For systems software and mission critical programs, it is a better or must-to-do practice to check the available filesystem space before actually writing to…
First time getting my hand on a plotter (HP Designjet 500) directly to print a poster, I found it was an interesting experience. But configuring the printer settings was not that straightforward compared to using normal office A4 printers. I took photos of how it was configured for reference of my own and also those…
I usually use iPhone in the English language. However, I find the iPhone calendar app includes a US holiday calendar subscribed while I am not in US and displaying US holidays in the iPhone calendar is no use and kind of annoying to me. After some investigation, I find the way to set the iPhone…
This post introduces how to play YouTube video in background on your iPhone. With this tip, you will need not to keep the YouTube app opening all the time. So you can use other apps on iPhone while listening to the music or talk or others from YouTube. This tip should also work on other…
It is useful to show the feed items directly on the webpage as HTML content. In this ost, we will show one single PHP function that fetches an RSS feed and outputs the feed items as HTML elements in the web page. One example to fetch an RSS feed and output the itmes as HTML…
Note that this was only tested on certain combinations like this (Windows 7 with iOS 8), this (Windows 7 with iOS 7), this and this (Windows 7 with iOS 9.3.2 (iphone 6s)). Windows 7 seems a possible Windows OS that can work. Recently, I tested it on Windows 8 and iOS 9. Unfortunately, it did…
Having to go the the server room to reset servers is the most headache thing for admins managing a cluster of Linux servers in a remote site. Either you can ping the server but can not ssh to it, or you even can not ping it. There are various reasons that may cause a Linux…
In Extending a Mounted Ext4 File System on LVM in Linux, we introduced how to extend a mounted ext4 filesystem on LVM Logical volume by adding a new physical volume. It is also common to shrink an ext4 file system as to spare some disk space. In this post, I will discuss how to shrink…
A pop-up terminal is great and handy on Linux and similar OS. On KDE, Yakuake is great. On Gnome or GTK, I ever tried Guake. It is quite good. However, it has not been as mature, stable and figure-rich as gnome-terminal. One day, I got this idea: why not using a script/program to manage the…
WhatsApp is a great messenger app on smart phones. There was ever some tricks to install WhatsApp app on iPod Touch or iPad. However, it is not possible now. But the good news is that the WhatsApp web is available so that users can use WhatsApp inside of a browser and the iPad or iPod…
If your website uses a self-signed certificates, Chrome will show a warning every time and you need clicks to continue. In this post, I will introduce how to make Chrome accept self-signed certificates for sites on Linux. This post is made short on purpose and you need to search the Web and learn if you…
My best favorite disk partition table manipulation tools are cfdisk/fdisk on Linux. However, for large disks, cfdisk/fdisk (of the versions by this post is written) will just give up with a message suggesting GPT partition table format and using GNU parted like WARNING: The size of this disk is 6.0 TB (6001042391040 bytes). DOS partition…
iPhone is nice to take videos. However, one headache is the video may be rotated by 90 degree if you play it with non-Apple software such as MPlayer on Linux or Windows. This tutorial will introduce how to rotate the video taken from iPhone or other sources on Linux by 90 degree. The tool we…
MPlayer is a great movie player. SSH is a great tool to connect and transfer data over the network securely. Combining these 2 great tools together will be greater. You may already has a small server storing some movies or videos or music and playing them on your laptop will be convenient. In this post,…
The Linux kernel has a generic driver for a graphic framebuffer named vesafb on intel boxes. It provides a nice large console for most of modern displays. Setting VESA modes for Linux kernel with 32-bit and 16-bit boot protocol are different. We introduce both methods here. Linux kernel with 32-bit boot protocol For machine with…
Hadoop 2 or YARN is the new version of Hadoop. It adds the yarn resource manager in addition to the HDFS and MapReduce components. Hadoop MapReduce is a programming model and software framework for writing applications, which is an open-source variant of MapReduce designed and implemented by Google initially for processing and generating large data…
LVM is a great tool to manage hard disks on Linux—you can abstract the hard drives away and manage logical volumes from volume groups, you can dynamically add or remove hard drives while the file systems on the logical volumes need not to backed up and recovered, and you may create many snapshots of the…
Ctrl keys are important and possibly most frequently used in Emacs. However, it is painful on today’s common PC keyboards since Ctrl keys are usually in the corner of the keyboard main area. Why the key mappings in Emacs are designed like this? After it was designed, Emacs was commonly on the Lisp Machine keyboards…
git merge is frequently used during development of projects managed by git. There are many common questions about git merge and I find most are solved and discussed on StackOverflow. Here, I summarize useful ones so that others who want to learn git merge need to do the search again. Merge, rebase, fast forward and…
In this post, creating a file-backed virtual block device (VBD) and installing Fedora 20 in the Xen DomU via internet will be introduced. This domain is created on a Fedora 20 Dom0 as introduced in https://www.systutorials.com/installing-xen-on-fedora-20-as-domain-0/. For better performance, you may consider using LVM backed VM. Create file-backed VBD The actual space of VBD will…