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CRDT, SSE, Hash tables, HTTP Headers, IIS, NTFS, Navigation, Hash functions, PowerShell

posted Nov 18, 2017, 10:32 PM by Sami Lehtinen   [ updated Nov 18, 2017, 10:32 PM ]
  • Conflict-free replicated data type (CRDT) - kw: Eventual consistency, Strong eventual consistency, Operation-based CmRDTs, State-based CvRDTs, Sequence CRDT.
  • Fingerprinting Firefox users with Cached intermediate CA certificates - Well. Isn't it pretty clear that any identifier which is stored and re-used / returned to server can be used to track users. That's why it's important to discard all data received from work from time to time. It doesn't matter if it's certificates, cookies or anything else which creates unique repeatable pattern / identifier. But still a good find, it's important that these things get noticed. Even this doesn't probably matter at all to normal users. Just like HSTS super cookies HSTS Super Cookie. This is also one of the reasons why I've been asking for per tab security. Just close the tab, and all the junk related to that tab / session is gone.
  • Found out that SSE 4.2 adds new instruction for computing CRC32.
  • Really nice technical post about fast hashtables. Also very nice charts, showing how hashtable load affects on performance.
  • OVH IPv6 address compression fail is still there, a full week later.
  • Had more long discussions about expires, last-modified, etag and cache-control max-age HTTP header values (headers). But there's clear use for each of those as well as those can be used efficiently as combination to improve performance, load time and reduce required bandwidth.
  • Had more fun configuring IIS and NTFS access rights, etc. It's obvious when you know what you're doing. But it might take a while to figure out what's exactly wrong. Before you know that it's obvious that it's incorrectly configured. Also configured system to use detailed error messages, which makes debugging early issues much easier.
  • Reminded my-self about old stuff, like aircraft navigation technologies - ILS (RDF, VOR, G/S, DME, Beacons) when I was using Microsoft Flight Simulator on 8086 with Hercules display (higher resolution than CGA). Yet as expected GPS boosted with WAAS, EGNOS, LAAS, D-GPS etc are taking over these legacy technologies. For many applications also Internet based Differential GPS sounds like great option. Like DGPS RTCM. In Finland visibility of geo static satellites is quite low, so mobile network + Internet will provide more available option, especially in northern parts.
  • Network Tools - for Android is pretty nice app. I've been using it for a long time. I also like how they've included HOTP TOTP OTP generators. Even if some people seem to confuse this with Google Authenticator.
  • Lifetimes of cryptographic hash functions - Very nice chart indeed. From theory to practice. I especially lowed the "slashdotter " / "hacker news" / "reddit" approach column. Very entertaining and accurate. What did I just mention in my last post. This really hit the sweet spot. Excellent humor with hard facts.
  • Checked out LTE Advanced (LTE-A, 4G+, LTE CAT 6, LTE CAT 9, LTE CAT 12, LTE CA, LTE 3CA). Because operators are actually rolling it out in volume now. This allows customers to use 300 Mbit/s Internet connection on their mobile phones. Yet the real speeds users are getting can be drastically lower.
  • Converted some of my old basic Python management scripts on Windows Server 2016 to use PowerShell. It's just very handy for small tasks on Windows Servers.