Comparing Digital Video Downloads of Interlaced TV Shows

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DVD

In the days of CRT monitors, TV shows used to be broadcast in interlaced mode, which is unsupported by modern flat-panel displays. All online streaming services and video stores provide progressive video, so they must deinterlace the data first. This article compares the deinterlacing strategies of Apple iTunes, Netflix, Microsoft Zune, Amazon VoD and Hulu by comparing their respective encodings of a Futurama episode. read more

Xbox Serial Number Statistics

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Slashdot had a story recently on how in 1942, the allies were able to estimate the number of German taks produced based on the serial numbers of the tanks. In 2010, a German hacker is doing the exact same thing with Xboxes. This article describes the generic approach, shows some results, and provides previously unreleased raw data of 14,000 Xbox serials so you can do your own statistics! read more

Measuring the ROR Bug in the Early MOS 6502

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The MOS 6502 CPU was introduced in September of 1975, and while the documentation described the three shift/rotate instructions ASL, LSR and ROL, the ROR instruction was missing – the documentation said that ROR would be available in chips starting in June 1976. In fact, the reason for this omission was that the instruction, while being present, didn’t behave correctly. Only few 6502s with the defect are in existence, and nobody seemed to have checked what was actually going on in these chips. read more

CPUID on all CPUs (HOWNOTTO)

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A while ago, an engineer from a respectable company for low-level solutions (no names without necessity!) claimed that a certain company’s new 4-way SMP system had broken CPUs or at least broken firmware that didn’t set up some CPU features correctly: While on the older 2-way system, all CPUs returned the same features (using CPUID), on the 4-way system, two of the CPUs would return bogus data. read more

Playstation 3 Hacking – Linux Is Inevitable

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In the talk “Why Silicon Security is still that hard” by Felix Domke at the 24th Chaos Communication Congress in 2007 (in which he described how he hacked the Xbox 360, and bushing had a cameo at the end explaining how they hacked the Wii), I had a little part, in which I argued that “Linux Is Inevitable”: If you lock down a system, it will eventually get hacked. In the light of the recent events happening with PlayStation 3 hacking, let’s revisit them. read more

Why is there no CR1 – and why are control registers such a mess anyway?

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If you want to enable protected mode or paging on the i386/x86_64 architecture, you use CR0, which is short for control register 0. Makes sense. These are important system settings. But if you want to switch the pagetable format, you have to change a bit in CR4 (CR1 does not exist and CR2 and CR3 don’t hold control bits), if you want to switch to 64 bit mode, you have to change a bit in an MSR, oh, and if you want to turn on single stepping, that’s actually in your FLAGS. Also, have I mentioned that CR5 through CR15 don’t exist – except for CR8, of course? read more

Intel VT VMCS Layout

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I understand that there might be a good reason for Intel to add virtualization extensions to their CPU architecture. Instead of fixing the x86 architecture to (optionally) make it Popek-Goldberg compliant and have all critial instructions trap if not run in Ring 0, they added non-root mode, a very big hammer that allows me to switch my CPU state completely to that of the guest and switches back to my original host state on a certain event in the guest. Well, it’s a great toy for people who want to play with CPU internals. read more

Microsoft vs. Standards

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Here is a fun game for long car rides: One person names a respected standard implemented by dozens of IT companies, and the other person names Microsoft’s competing technology. Example: MPEG Audio (MP3/AAC) – Windows Media Audio. read more