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New features of the hybrid monitoring AIOps system Monq

Gals Software corporate blog IT systems testing *System administration *IT Infrastructure *Software

In one of the previous articles, I’ve already written about the hybrid monitoring system from Monq. Almost two years have passed since then. During this time, Monq has significantly updated its functionality, a free version has appeared, and the licensing policy has been updated. If monitoring systems in your company start to get out of control, and their number rushes somewhere beyond the horizon, we suggest you take a look at Monq to take control of monitoring. Welcome under the cut.
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Total votes 9: ↑9 and ↓0 +9
Views 313
Comments 0

Десятка лучших frontend-сообществ и каналов

Конференции Олега Бунина (Онтико) corporate blog JavaScript *Conferences Design

Что может быть ценнее новых идей и нового опыта? Только возможность обсудить их вместе с людьми, которые в теме. 

Мы решили сделать для вас подборку самых интересных frontend-сообществ и полезных каналов на YouTube для разработчиков JavaScript и веб-дизайнеров.

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Total votes 24: ↑23 and ↓1 +22
Views 2.1K
Comments 0

Quantitative‌ ‌Funds:‌ ‌What’s‌ ‌Interesting‌ ‌for‌ ‌Coders?

Luxoft corporate blog Big Data *Machine learning *IT career Finance in IT

Hello, Habr! Not only traders but also mathematicians and programmers work with stock markets. Director of Engineering at Luxoft Artem Sosulnikov tells about data, which specialists of quantitative hedge funds work with, things they pay attention to, and conditions in such companies.

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Total votes 1: ↑1 and ↓0 +1
Views 617
Comments 0

Tutorial: how to port a project from Interop Word API to Open XML SDK

PVS-Studio corporate blog Programming *.NET *C# *Development for Office 365 *

With the .NET5 release further development of some projects was questionable due to the complexity of porting. One can abandon small outdated libraries or find a replacement. But it's hard to throw away Microsoft.Office.Interop.Word.dll. Microsoft doesn't plan to add compatibility with .NET Core/5+, so in this article we focus on creating Word files with Open XML SDK.

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Total votes 4: ↑3 and ↓1 +2
Views 668
Comments 0

Controlling Brushless Motors using a Linux computer or a PLC

*nix *SCADA *Computer hardware DIY Electronics for beginners

In this video, we will look at how to connect brushless motor controllers to a Linux computer. Specifically, we will use a computer running Debian. The same steps would work for Ubuntu Linux and other Linux distributions derived from Debian.

I've got a small sensorless brushless motor, and a bigger brushless motor with a built-in absolute encoder. Lets look at how to control those from my Debian Linux computer. Servosila brushless motor controllers come in several form factors with either a circular or a rectangular shape. The controllers come with a set of connectors for motors and encoders as well as for USB or CANbus networks.

The controllers can be powered by a power supply unit or by a battery. To spice up my setup, I am going to use a battery to power the controllers and thus their motors. The controllers need 7 to 60 volts DC of voltage input. If I connect the battery, the controllers get powered up. The small LED lights tells us that the controllers are happy with the power supply.

We need to connect the brushless motor controllers to the Linux computer. There are two ways to do that - via CANbus or via USB. Lets look at the USB option first. A regular USB cable is used. Only one of the controllers needs to be connected to a computer or a PLC.

Next, we need to build an internal CANbus network between the controllers. We are going to use a CANbus cross-cable to interconnect the controllers. Each controller comes with two identical CANbus ports that help chain multiple controllers together in a network. If one of the interconnected brushless motor controllers is connected to a computer via USB, then that particular controller becomes a USB-to-CANbus gateway for the rest of the network. Up to 16 controllers can be connected this way via a single USB cable to the same control computer or a PLC. The limit is due to finite throughput of the USB interface.

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Total votes 4: ↑3 and ↓1 +2
Views 733
Comments 0

Шпаргалка по CSS свойству display

Привет, Хабр. Я часто вижу, что разработчики плохо знают, как работает свойство display. Это приводит к разного рода ошибкам. Чтобы побороть это, я собрал наиболее популярные значения и описал, как они влияют на элемент. Все эксперименты я выложил в виде шпаргалки на Codepen, чтобы вы могли проинспектировать их и изучить.

P.S. Если я что-то пропустил, то поправляйте меня в комментариях. Спасибо!
Total votes 3: ↑3 and ↓0 +3
Views 1.1K
Comments 0

CodeIgniter 4. Prelude to PHPUnit

PHP *CodeIgniter *

Thanks for your feedbacks

I thank the members of the Habr community for their benevolent attitude to the article by the author «Speed Dating with the CodeIgniter 4 on GitHub» in the form of votes and comments.

The friendly attitude to the author prompted him to continue developing a topic dedicated to PHPUnit as part of CodeIgniter 4.

Install Xdebug on XAMPP (Windows 32-bit (x86))

1. Why Xdebug? In file «appstarter/tests/README.md» in the «Requirements» section explicitly states: «You also need to install XDebug to successfully calculate code coverage».

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Total votes 1: ↑0 and ↓1 -1
Views 446
Comments 0

Is PHP compilable?! PVS-Studio searches for errors in PeachPie

PVS-Studio corporate blog PHP *.NET *Compilers *C# *

PHP is widely known as an interpreted programming language used mainly for website development. However, few people know that PHP also has a compiler to .NET – PeachPie. But how well is it made? Will the static analyzer be able to find actual bugs in this compiler? Let's find out!

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Total votes 2: ↑2 and ↓0 +2
Views 243
Comments 0

Controlling Brushless Motors from Windows

Robotics development *Development for IOT *Development for Windows *Robotics IOT

In this video, we will look at how to connect brushless motors to a Windows computer via USB. We are going to connect a network of Servosila brushless motor controllers to the computer. The other option is CANbus interface, but we will look at CANbus in a dedicated video. A regular USB cable is used. Note that the USB cable is not used to power the controller and its motor.

The first brushless motor controller in network appears to Windows as a Virtual COM port. Once connected via USB, it can be found in a general list of devices in the Window's "Settings" window. Up to 16 controllers can be connected this way via a single USB cable to the same control computer or a PLC. If one of the interconnected brushless motor controllers is connected to a computer via USB, then that particular controller becomes a USB-to-CANbus gateway for the rest of the network.

If your computer happens to have more that one serial port, you may wish to check a COM port's number assigned by Windows to the controller. Then, you pick this COM port in a drop down menu in the Servoscope software, and click Connect. If the COM port is not listed in the drop-down menu, click the Refresh button. If everything is good, the controller appears in a list of devices. Double-click to open up a control and configuration window.

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Total votes 5: ↑3 and ↓2 +1
Views 489
Comments 0

System-on-Chip bus: AXI4 simplified and explained

FPGA *Robotics development *Programming microcontrollers *Circuit design *Manufacture and development of electronics *

Protocol AXI4 was developed for High-bandwidth and low latency applications. It is designed to allow communication between master and slave devices. Master is typically a DMA or CPU and slaves are DRAM controllers, or other specific protocol controllers: UART, SPI, and others. Sometimes one component can implement multiple instances of this protocol. Usually, a prefix is used to differentiate between multiple AXI4 interfaces.

For example, Ethernet MAC can integrate DMA and slave interface used to command MAC. MAC can accept commands on the slave interface that contain data about the location of the next ethernet packet and MAC can start fetching this packet using the separate master interface instance.

This article was motivated by common design mistakes AXI4 designers make when they are designing their Digital IP. (Looking at you Xilinx)

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Total votes 10: ↑10 and ↓0 +10
Views 926
Comments 0

Private party protocol: how to distinguish friends and foes using cryptographic tools

Information Security *Cryptography *Network technologies *

ENCRY presents a new interactive identification protocol aimed at controlling the access of selected users to various resources.

Close your eyes and imagine Nice, a luxurious estate whose extravagant owner throws epic parties with jazz and fireworks every weekend.

To attend such a party is a lot of the elite. Invitations are sent out in advance, and guests do not know the names of other invited persons. The owner of the estate, the mysterious Jay Gatsby, an eager luxury-lover, values ​​privacy so much that he is not ready to entrust the list of invitees to anyone, not even his buttress. Moreover, the owner of the estate would like the guests not to reveal their names when entering the property. After all, there may be the mayor of the city, or the chief prosecutor among them, and they would like to keep their visit secret. Unfortunately, the owner of the estate himself is so busy that he cannot independently check each guest at the entrance, especially since there are several access roads to his house. How could he solve this problem?

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Total votes 2: ↑2 and ↓0 +2
Views 626
Comments 0

Doubling effective digitization frequency by multiple pass approach, is it possible?

Algorithms *Programming microcontrollers *DIY

As already described in the previous article, in the process of reworking the DSO138 oscilloscope toy, the idea arose in the DSO303 firmware at some point to try to double the maximum sampling frequency to achieve scanning times of 500 and 200 nanoseconds per cell. In fact, for the STM32F303, the theoretically maximum achievable sampling rate from the point of view of the ADC input, and this is determined by the minimum opening time of the ADC sampling unit, which in our case is 1.5 clock cycles x (1/72 MHz) = 20.8 nanoseconds, is 48 MSPS (millions of counts per second). However, with the parallel operation of 4 ADCs at 6 MHz, it is possible to achieve only 24 MSPS due to the limited speed of the ADC.

Let's imagine that we are considering correctly-periodic signal, which is also constant, i.e. it does not experience fluctuations in frequency and amplitude over time. Is it possible to somehow digitize it not in one, but in several passes, thereby increasing the effective sampling frequency? 

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Rating 0
Views 410
Comments 0

DSO138 upgrade

Programming microcontrollers *Circuit design *DIY Electronics for beginners

On Ali, an interesting toy – an oscilloscope called DSO138 is sold for a very inexpensive price. It has already gained quite a lot of popularity among electronics lovers, but the parameters of this device, alas, allow it to be more or less fully used only for debugging very low-frequency circuits. Actually, it is not positioned as a tool, but rather as a DIY-kit for novice electronics engineers.

This "toy" oscilloscope is assembled on the STM32F103 microcontroller, and with a fairly competent circuit design of the digital part, the presence of a fairly decent 320X240-dot color display, and not the most rotten analog path, everything, alas, is ruined by very weak ADCs on board the 32F103. The claimed band of 200 kHz can be recognized as such only with a very large stretch. Yes, it will show the presence or absence of a signal with such a frequency, but it will not be possible to really look at something beyond this.

At the same time, the 103-series has a slightly more powerful brother - the STM32F303, it is almost completely compatible with the legs, but it is significantly better in terms of the parameters we are interested in, there are 4 ADCs on board with a conversion frequency of 5 MHz (6 MHz with a 10-bit resolution). In this scenario, if you use all 4 ADCs in parallel with a 10-bit resolution, you can get a effective resolution of up to an honest 24 MSPS (millions of samples per second). The microcontroller is also inexpensive; you can easily find it on the same Ali for very reasonable money again. It is clear that the idea to change the microcontroller arose almost immediately after I tried this DSO138.

At the same time, if upgraded the toy can turn out to be a completely full-fledged tool that even professionals, not just novice amateurs, could already use. With these thoughts in mind, I decided to try to do something with a Chinese toy in my free time.

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Total votes 5: ↑5 and ↓0 +5
Views 712
Comments 0

Controlling Brushless Motors using Raspberry PI

Robotics development *Development for IOT *Development for Raspberry Pi *Robotics IOT

In this video tutorial, we will control a pair of brushless motors from a Raspberry PI computer. We will use one of the computer's USB ports to connect a network of brushless motor controllers. We will power the computer, the controllers, and the brushless motors using a single battery, similar to a autonomous vehicle design.

The first motor is an outrunner type, a kind of what you would use for a vehicle propulsion. The bigger motor comes with a quadrature encoder which means it can be used as a powerful servo.

I made a cable to power my set up. On one end, the cable has a socket for plugging the battery. The cable splits into a two parallel parts to power the controllers, and the Raspberry PI. The bottom part of the cable further splits to power a pair of brushless motor controllers.
By the way, the controllers need 7 to 60 Volts DC. I put proper connectors at the ends of the cable, so that I could just plug it into the controllers.

Servosila brushless motor controllers come in rectangular or circular form factors. The controllers have USB and CANbus ports for connecting to control computers such as Raspberry PI.

Video & Read More
Total votes 6: ↑5 and ↓1 +4
Views 726
Comments 0

Optimization of .NET applications: a big result of small edits

PVS-Studio corporate blog .NET *C# *


Today we're going to discuss how small optimizations in the right places of the application can improve its performance. Imagine: we remove the creation of an extra iterator in one place, get rid of boxing in the other. As a result, we get drastic improvements because of such small edits.

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Total votes 6: ↑4 and ↓2 +2
Views 760
Comments 0

VSCode: how to view reports of static analyzers that support SARIF

PVS-Studio corporate blog Visual Studio *

People increasingly start optimizing the process of finding code errors using static analyzers. Nowadays, we can choose from a variety of products to view analysis results. This post covers the ways how to view an analyzer report in the most stylish and feature-rich IDE among multifunctional ones – VSCode. The SARIF format and a special plugin for it allow us to perform our task. Keep reading to find out about this. Let's get going!

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Total votes 3: ↑3 and ↓0 +3
Views 385
Comments 0

How to see and save Instagram requests on an android device

Reverse engineering *

Once I was asked to save a traffic dump of an Instagram app while viewing one particular user profile. Simply saving the traffic dump on the router didn't make sense because the app used TLS to communicate with the server. Existing solutions didn't work because they worked with an older version of Instagram.

Below I will describe how I managed to do it myself using mitmproxy, ghidra and frida.

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Rating 0
Views 883
Comments 0

Improving the quality and formatting of the code in the TypeScript

JavaScript *Node.JS *Start-up development TypeScript *

With the help of the ESLint and Prettier features, you can automate the formatting of your code, make it more expressive and accurate, correspond to specific rules, and avoid errors and bottlenecks even before uploading the code to the shared source storage...

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Total votes 1: ↑0 and ↓1 -1
Views 739
Comments 2