In C++ programming, data structures are essential for organizing and manipulating data. When it comes to storing and manipulating data, one data structure stands out above the rest – the std::vector. Efficient Memory Allocation One of the primary benefits of std::vector is its efficient memory allocation. std::vector uses contiguous memory allocation, which means that the…
This post summarizes Linux Kernel new features, bugfixes and changes in Linux 4.19.178 Release. Linux 4.19.178 Release contains 248 changes, patches or new features. In total, there are 239,909 lines of Linux source code changed/added in Linux 4.19.178 release compared to Linux 4.19 release. To view the source code of Linux 4.19.178 kernel release online,…
This post summarizes Linux Kernel new features, bugfixes and changes in Linux 4.14.223 Release. Linux 4.14.223 Release contains 176 changes, patches or new features. In total, there are 277,921 lines of Linux source code changed/added in Linux 4.14.223 release compared to Linux 4.14 release. To view the source code of Linux 4.14.223 kernel release online,…
This post summarizes Linux Kernel new features, bugfixes and changes in Linux 5.4.102 Release. Linux 5.4.102 Release contains 338 changes, patches or new features. In total, there are 160,715 lines of Linux source code changed/added in Linux 5.4.102 release compared to Linux 5.4 release. To view the source code of Linux 5.4.102 kernel release online,…
This is the release notes for linux release v0.97 with format adjusted by removing/replacing tabs/spaces/new lines. This notes document can give us an understanding of the early development of the Linux kernel. The original ASCII formatted version is at the end of this post. Changes in 0.97: The VESA-support was removed. I’d be happy to…
This is the release notes for linux release v0.95 (source code: linux-0.95.tar.gz) with format adjusted by removing/replacing tabs/spaces/new lines. This notes document can give us an understanding of the early development of the Linux kernel. The original ASCII formatted version is at the end of this post. RELEASE NOTES FOR LINUX v0.95 Linus Torvalds, March…
DNF/YUM can automatically download the RPM packages and install them. Under some situations, we may prefer to make a copy of the RPM files for offline usage so that no need to have network connections to install the software packages. For such purposes, we need to make a copy of the RPM packages. It is…
Hyperledger Fabric is a consortium blockchain system. It’s performance is relatively good and its modular architecture enables it to be usable in many scenarios. Hyperledger Fabric itself has rich documents and samples of test networks. For beginners, deploying a new network for trying and testing still consumes quite some time. In this post, we will…
Since version 7, RHEL and CentOS only have 64 bit versions. For some reasons, it’s better to run many Windows applications under 32 bit wine. Like How to Install Wine 32-bit on CentOS 7, this post introduce how to install 32-bit Wine on CentOS 8. Most of the mechanisms are similar yet there are differences….
Google Drive is a nice cloud storage service. It provides a suite of nice online document spreadsheet and slide editors Google Docs, Google Sheets and Google Slides. The collaborative editing and full history tracking features of Google Docs are excellent. Google Drive gives 16GB free storage which is pretty much larger compared to other free…
In Ubuntu 18.04, Thunderbird shows huge emoji icons in the email list. The emoji covers other text and is several lines higher and wider than other charactors. How to solve it? This is likely caused by the fonts. Find out the *emoji* fonts installed in your system by sudo apt list *emoji* and remove those…
How to create a file if not exist and open it in read and write modes in C++? For example, I would like open a fstream on /tmp/cache to be able to read it and append to it. If the file does not exist yet, create one. A simple code like std::fstream fs(“/tmp/cache”, std::ios::in |…
NUMA Architecture: Non-Uniform Memory Access architecture. SMP: Symmetric Multiprocessing architecture. In a Symmetric Multiprocessor, the architectural “distance” to any memory location is the same for all processors, i.e. “symmetric”. In a NonUniform Memory Access machine, each processor is “closer” to some memory locations than others; i.e. memory is partitioned among them Asymmetrically. From my understanding,…
PARSEC is the most important CPU-bound benchmark for systems. It is huge and hard to install because it needs lots of 3-part libs. PARSEC download link for 3.0 version: http://parsec.cs.princeton.edu/download.htm#parsec I remembered I added the answer yesterday night but I could not see the answer currently. Anyway, let me add the answer again after I…
Where can I find the source code for the free command on Linux? The source code for the free commands (and many more, like kill, ps, top, sysctl) can be found in procps-ng: https://gitlab.com/procps-ng/procps procps is a set of command line and full-screen utilities that provide information out of the pseudo-filesystem most commonly located at…
Hi there, Quite recently I’ve created a native app (webview app)of my wordpress website and this wordpress site is using responsive theme as well. Now I want to publish this app at play store. The problem is that Adsense are not allowed to be shown in a native android app. So I want to know…
I would like to check whether the domain name’s IP has changed in the authoritative DNS server. The system’s configured DNS server may still cache the old IP, which is fine. The question is how to query from the authoritative DNS server the new IP? You can use dig – DNS lookup utility to query…
I can only connect to a Linux server by SSH. How to check whether a USB disk is connected to the Linux server? 2 ways I usuaully use: Method One: Check the print out of dmesg After the USB storage is connected and detected by Linux, it may print some messages containing “[sde]” (the new…
In hadoop I need to skip mapper function and directly execute the reducer function. We doing this to improve hadoop performance, if the hadoop framework is used to analyze same data sets, then mapper’s output will be same for different kind of jobs. To save the redundant computation for same results, I am planning to…
How to exclude directories with certain names like “cache” from rsync on Linux during backup? The “cache” directory may in many different paths, such as file1/cache/ or file2/cache/, and adding all “cache” directories to rsync command is not a doable way. You can use rsync with –exclude=cache/ like rsync -avxP –exclude=cache/ /path/to/src/directory/ /path/to/dst/dir/