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  • R.I.P. Sir Clive Sinclair

    Posted on September 17th, 2021 admin No comments

    Another day of sadness to mark on the calendar, as someone has written on the World of Spectrum forum. He passed away on 2021.09.16 at the age of 81. I owe my interest and love in computers to him. Rest in peace Sir!

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  • Localhost tcp traffic stalled

    Posted on April 28th, 2021 admin No comments

    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 ( 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

    Posted on November 11th, 2020 admin No comments

    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

    Posted on November 11th, 2020 admin No comments

    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

    How much is 256 bytes.

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  • Configure WSUS/GPO programmatically

    Posted on June 22nd, 2019 admin No comments

    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

    Posted on February 19th, 2019 admin No comments

    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

    Posted on February 3rd, 2019 admin No comments

    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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  • Hacking the SjASMPlus Z80 assembler

    Posted on November 1st, 2016 admin No comments

    I like SjASMPlus because it is small, portable (one exe, no install) and supports writing SNA format, which means it can directly assemble the source into SNA emulator snapshot file. This is very handy if disassembling a snapshot, reverse engineering the code, then comparing the compiled source with the original snapshot. However it has a minor drawback.

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  • Slow page load (IPv6) with Internet Explorer 11

    Posted on November 21st, 2015 admin No comments

    Recently, I found a website which loads very slowly in Internet Explorer 11 (under Windows 7) while other browsers did not affected (Chrome, Firefox). The site has both IPv6 and IPv4 addresses. Tcpdump showed that connection to the IP address is failed, Destination unreachable ICMPv6 messages returned in reply to SYN packets.

    Despite the address is unreachable the operating system retransmists the SYN packets in a 9 seconds interval. There was a 12 seconds silence, and after a total waiting of 21 seconds the browser switched to the IPv4 address then the connection established under 2 milliseconds. Google Chrome behaves differently: after 300 milliseconds of the first failed IPv6 SYN attempt it immediately switched to IPv4 which is cannot be noticeable by the user. No annoying waiting, no unnecessary retransmissions.

    An hour surfing on the net did not reveal any valid explanation. Interestingly, Internet Explorer 9 suffers from the same phenomena. I suppose this is by desing albeit very frustrating.

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  • Delphi compile timestamp

    Posted on November 21st, 2015 admin No comments

    It could be useful to know the build date of the executable. In most situations this is the file’s timestamp.
    It is quite simple to read it out in TDateTime format:

    ExeDate := FileDateToDateTime(FileAge(ParamStr(0)));

    However, there are situations when the file’s timestamp is altered and the build date is lost.

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