20 Linux System Monitoring Tools Every SysAdmin Should Know Need to monitor Linux server performance? Try these built-in commands and a few add-on tools. Most Linux distributions are equipped with tons of monitoring. These tools provide metrics which can be used to get information about system activities. You can use these tools to find the possible causes of a performance problem. Finding out bottlenecks.Disk (storage) bottlenecks.CPU and memory bottlenecks.Network bottlenecks. #1: top - Process Activity Command The top program provides a dynamic real-time view of a running system i.e. actual process activity. Fig.01: Linux top command Commonly Used Hot Keys The top command provides several useful hot keys: => Related: How do I Find Out Linux CPU Utilization? #2: vmstat - System Activity, Hardware and System Information The command vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity. # vmstat 3 Sample Outputs: Display Memory Utilization Slabinfo # vmstat -m Get Information About Active / Inactive Memory Pages
Dual Monitor Tools - Home page Lantern: One Device, Free Data From Space Forever Global access to the web’s best content on your mobile device. Anonymous. Uncensored. Free. “The Short Wave Radio for the Digital Age.” -- Fast Company “A Tiny Satellite Dish That Brings Info to the World’s Deadzones.” -- Wired “Outernet aims to provide data to the net unconnected.” -- BBC "Billions of people around the world don't have access to the Internet, so the next big thing is trying to connect the world." -- CNN Lantern is an anonymous portable library that constantly receives free data from space. Like the water we drink or the air we breathe, the information we consume feeds the very essence of what it means to be human. Lantern continuously receives radio waves broadcast by Outernet from space. Oh, and Outernet is free to use, always. How much is 10 MB per day? When purchasing Lantern through this campaign, you are both advancing the collective potential of our species and receiving a cutting-edge piece of technology. Buy a Lantern, support Outernet, and help us find the answers.
EDN - Simultaneous multi-channel UHF data reception in automotive transceivers Technology introduced by NXP is claimed to deliver improved RF performance to bring a new dimension to 2-way applications, with significant reduction in overall power consumption Page 1 of 3 Building on its automotive electronics and its commitment to connecting the car, NXP Semiconductors has introduced the NCK2983, a low-power multi-channel two-way UHF transceiver with an embedded microcontroller system that can uniquely receive up to three channels in parallel rather than sequentially. Existing multi-channel transceivers are only able to poll for signals sequentially, one channel after another, in order to check every possible frequency that an application may be transmitting on. The NCK2983 is able to receive multiple channels in parallel because it uses a pioneering Wideband Digital IF approach.
Top 20 Nginx WebServer Best Security Practices Nginx is a lightweight, high performance web server/reverse proxy and e-mail (IMAP/POP3) proxy. It runs on UNIX, GNU/Linux, BSD variants, Mac OS X, Solaris, and Microsoft Windows. According to Netcraft, 6% of all domains on the Internet use nginx webserver. Default Config Files and Nginx Port /usr/local/nginx/conf/ - The nginx server configuration directory and /usr/local/nginx/conf/nginx.conf is main configuration file. You can test nginx configuration changes as follows: # /usr/local/nginx/sbin/nginx -t Sample outputs: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok configuration file /usr/local/nginx/conf/nginx.conf test is successful To load config changes, type: # /usr/local/nginx/sbin/nginx -s reload To stop server, type: # /usr/local/nginx/sbin/nginx -s stop #1: Turn On SELinux Security-Enhanced Linux (SELinux) is a Linux kernel feature that provides a mechanism for supporting access control security policies which provides great protection. Do Boolean Lockdown
Learnable Programming Here's a trick question: How do we get people to understand programming? Khan Academy recently launched an online environment for learning to program. It offers a set of tutorials based on the JavaScript and Processing languages, and features a "live coding" environment, where the program's output updates as the programmer types. Because my work was cited as an inspiration for the Khan system, I felt I should respond with two thoughts about learning: Programming is a way of thinking, not a rote skill. Learning about "for" loops is not learning to program, any more than learning about pencils is learning to draw.People understand what they can see. Thus, the goals of a programming system should be: to support and encourage powerful ways of thinkingto enable programmers to see and understand the execution of their programs A live-coding Processing environment addresses neither of these goals. Alan Perlis wrote, "To understand a program, you must become both the machine and the program."
untitled Wireless Short Range Devices and Narrowband Communications Wireless Short Range Devices and Narrowband Communications By Conor O’Mahony, Applications Engineer, Analog Devices Introduction The term “Short Range Device” (SRD) covers radio transmitters which provide either unidirectional or bi-directional communication and which have a low capability of causing interference to other radio equipment. Due to the many different services provided by these devices, there is no exhaustive list covering the SRD application space, however, the following categories are amongst those covered: • Telecontrol for Home/Building Automation Systems • Automatic Meter Reading • Wireless Sensor Applications • Medical Telemetry • Alarms • Automotive, including Remote Keyless Entry & Remote Car Start Applications When designing a SRD wireless system, careful consideration needs to be paid to the choice of frequency on which your radio will be communicating over and also the specified frequency plan required by the regulations in that particular region.
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