Localhost tcp traffic stalled

After installing a 4G/LTE USB stick on a Windows 7 desktop the TCP communication on localhost has effectively stalled. Interestingly, the remote traffic was not affected. Local services can be reached by remote clients and remote services can be accessed from the desktop, only the localhost (127.0.0.1) is affected. Still ping (ICMP) works on localhost as before. Capturing the traffic reveals that all localhost services communicate through TCP become utterly slow. The TCP session starts by a zero window packet in both direction right after the SYN-SYN/ACK handshake. After that, only 1 byte payload arrives in 20-60 seconds interval. Most clients give up after 30 seconds and return error. The problem persist after removing every installed software and turning off the Windows Defender service. It doesn’t matter which port the service is listening on.

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Bomberman / Dynablaster DX11

This is a quick update to the version I published many years ago. A lot has changed under the hood and yet much remains the same.

Click on the picture to download the game

Basically, the DirectX 9 API was replaced by Direct 3D 11 and a few minor bugs was fixed. We played a lot with this version on Windows 10 so I believe it’s free of bugs.

Added benefit of the new API is that you don’t have to download a DirectX runtime from Microsoft anymore. It should be working immediately without any additional download, at least on Windows 10.

The menu is as plain as in the original Amiga (or PC) version. This is intentional, it’s like playing in an emulator. However, I hope I will release a more user friendly advanced version soon.

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256b demo – Function 2019

Some people think 256 bytes doesn’t enough for anything. To be prove they’re wrong just watch “Puls by Rrrola” or “Stainless Steel by Digimind” on Youtube. You can find more jaw-dropping products if you search for “256b demo”.

I created a simple waving-colors effect which was called color-plasma in the old demo days. As simple as it is but looks mesmerizing. I called it Hypnotize. If you watch it long enough you will know why.

Click to download from ftp.scene.org

How much is 256 bytes.

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Configure WSUS/GPO programmatically

We have a few hundred Windows PCs across the country. It is essential to keep the OS up to date, just think of the new BlueKeep vulnerability. These PCs are running 7/24 unattended, so we need to automate almost everything, including the Windows Update configuration. These PCs are completely separate from the intranet and do not connect to the Windows Domain, but they have to use the company’s WSUS servers. Each computer had the WSUS server pre-configured using the Local Group Policy (gpedit.msc), but after a few years we had to change the server address. Each PC is supervised by our custom management software. It was obvious that the WSUS server setting should be deployed through the same management system, as well as other settings. Read the rest of this entry »

Rise and fall of WAP

In the perspective of an engineer…

I started working as a Service Quality engineer at a telecom company in 2001. After many small projects a manager asked me whether I can create a software to grab the content of our entire mobile site to verify everything, literally (broken links, grammar, changes, pictures etc). Mobile sites were using WAP technology back then and there was no deep knowledge on how to communicate via the WAP protocol. I got a small byte array (less than 50 bytes long) from a WAP Gateway operator which meant to be the WAP request. The software used it to generate the WAP request by appending the URL to it. That was a simple WAP Class 0 (connectionless) transaction. I sent one UDP packet with the request then the WAP Gateway sent me the response. That was it.

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Software controlled infrared device

After a long silence I pushed myself to create a new article. I have many half written materials I can choose from. This time I finished my IR device story.

In 2008 my then boss came up with an idea: End-to-End testing/monitoring of the TV services by using real set-top-boxes (STB). One of the interesting part of this project was the development of the software controlled infrared remote device. E2E mean we had to control an STB just like clients do, so a computer controlled IR had to be developed. We intended to simulate the original remote, so I had to watch-and-learn the signal it sent.

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Microcontroller music

Many years ago I wanted to create an indoor game which requires an explosion sound effect. I opted for a microcontroller because it’s cheap and easy to program. But didn’t know exactly how to produce that explosion sound. It was obvious that I have to synthesize the sound instead of playing a recorded sample.
First a PRNG (Pseudorandom Number Generator) came to my mind but it produces a white noise which is not quite like a boom effect. That’s why I turned to ZX Spectrum beeper music. Those guys in 80s did great sound effects with an 8-bit CPU and a simple buzzer.

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Bomber Man / Dyna Blaster for Windows

Bomber Man may be the more popular name of this game, but in 1992 for me it was Dyna Blaster on the Amiga. In 2010 I converted the Amiga version to Windows. This game has so many conversions but it was fun to made my own version. Tests were successful on Windows XP and Windows 7 (32-bit and 64-bit). It’s just a single exe, no install is required.

Click on the picture to download the game

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Introduction…

The main purpose of this site is to preserve my own work, mostly computer software and electronics related stuff.