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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for October 12th, 2017

The cloud has no walls: cache-based jamming agreement to communicate over the CPU cache even without rights

Posted by jpluimers on 2017/10/12

Oh boy: [WayBack] Alles kaputt: In der Cloud gibt es keine Wände.  – Kristian Köhntopp – Google+:

Two Amazon EC2 instances communicating over the CPU cache without the need of a network in-between them.

Open sourced foundations: IAIK/CJAG: CJAG is an open-source implementation of our cache-based jamming agreement.

In our BlackHat Asia 2017 Talk we show that the cache covert channel we built is so fast and reliable that we can do much more than tunneling SSH over it: We show that we can even stream a music video in decent quality through the cache – on the Amazon EC2 cloud.

See the BlackHat Asia Briefings Information here: https://www.blackhat.com/asia-17/brie…

See a video of the Live Demo here: https://www.youtube.com/watch?v=yPZmi…

Find our NDSS 2017 paper here: https://gruss.cc/files/hello.pdf

–jeroen

Read the rest of this entry »

Posted in Development, Hardware Development, Security, Software Development | Leave a Comment »

ThreadBarrier/ThreadBarrier.pas at master · lordcrc/ThreadBarrier

Posted by jpluimers on 2017/10/12

I mentioned Asbjørn Heid on wiert.me before. While prepping for the Deadlock Empire workshop at EKON20, I needed a Delphi equivalent for the .NET [Way: Barrier Class (System.Threading)

The game uses that in level deadlockempire.github.io/#H4-Barrier [WayBack].

Edwin van der Kraan found the ThreadBarrier/ThreadBarrier.pas at master · lordcrc/ThreadBarrier implementation via [WayBack] Is there a way to create memory barriers in Delphi? Something like .NET’s System.Threading.Barrier class, java.util.concurrent.CyclicBarrier… – Horácio Filho – Google+

It’s from Asbjoørn who is known as lordcrc on GitHub. Cool stuff!

So yes, there is a Delphi version of If you thought you could do multi-threading, then play “The Deadlock Empire” games. You can find it at https://deadlockempire.4delphi.com/ There are two deadlockempire implementations there:

The workshop was great fun!

This is about a web game focussing on the concurrency issues in multi-threading environments. By the conference there will be a Delphi version of it. At the workshop we will play each round interactively: all attendees play the round followed by a short discussion. This is about collective learning, so the speakers will probably learn… Read More

Source: [Archive.is] If you thought you could do multi-threading, then play “The Deadlock Empire” games – Entwickler Konferenz

–jeroen

Posted in .NET, C#, Delphi, Delphi 10 Seattle, Delphi 10.1 Berlin (BigBen), Delphi XE, Delphi XE2, Delphi XE3, Delphi XE4, Delphi XE5, Delphi XE6, Delphi XE7, Delphi XE8, Development, Software Development | 1 Comment »

HTML indentation: 2 spaces

Posted by jpluimers on 2017/10/12

Using too many editors in too many environments, tabbed files usually kills my productivity.

Not just because the structure of the indented code, also because most editors are stupid enough to also use tabs beyond the indentation, for instance for carefully aligned initialisation statements.

Changing the tab-size effectively waves good bye to those.

It’s weird (Wiert loves that word) that HTML peeps even argue about tabs versus spaces:

Most people still use HTML for pixel perfect rendering and spaces help getting character perfect rendering of the source code.

I was glad to bump into [WayBack] Jefferson Lima answering this on Stack Overflow:

The Google HTML/CSS Style Guide and the W3School HTML(5) Style Guide recommend 2 spaces.

This article also brings an analysis of the effect of tabs vs spaces in the resulting file size.

Source: [WayBack] html5 – html indenting standard, tab or two spaces? – Stack Overflow

So: use 2 spacec for HTML indent.

It doesn’t really matter in transmitted size (minified compressed transfer difference is ~0% and the usual image bloat is way larger than the HTML anyway – just try www.webbloatscore.com and watch).

References:

  • Indent by 2 spaces at a time.
  • Don’t use tabs or mix tabs and spaces for indentation.

Source: [WayBack] Google HTML/CSS Style Guide

  • Do not add blank lines without a reason.
  • For readability, add blank lines to separate large or logical code blocks.
  • For readability, add two spaces of indentation. Do not use the tab key.
  • Do not use unnecessary blank lines and indentation. It is not necessary to indent every element.

Source: [WayBack] HTML5 Style Guide

Tabs Spaces Saving
Raw file size 1403 bytes 1703 bytes 300 bytes/18%
Raw file GZipped   327 bytes   332 bytes      5 bytes/1.5%
Raw file minified 1199 bytes 1199 bytes      0 bytes/0%
Minified & GZipped   312 bytes   312 bytes      0 bytes/0%

When minified, it doesn’t matter if tabs or spaces are used, since they are all stripped away.

Source: [WayBack] Effect of tabs vs. spaces in HTML files

–jeroen

Posted in Development, HTML, Software Development, Web Development | Leave a Comment »

 
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