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Comment Frequency Hopping vs Direct Sequence (Score 4, Informative) 67

I don't mean to denigrate her contribution in any way, but Lamarr's frequency-hopping spread spectrum is not the one used in CDMA mobile phones. It is used in Bluetooth.

Lamarr invented "frequency hopping" while CDMA cellular and GPS use "direct sequence". Frequency hopping is just what it sounds like: a narrowband transmitter is continually retuned to a different radio channel. Unless the receiver tuning follows the same sequence at the proper times it cannot receive the transmission.

Direct sequence XORs a narrowband signal with a high speed pseudorandom "chip" sequence, and the receiver undoes this operation by XORing it again by the same sequence properly synchronized in time. It closely resembles a keystream-type encryption system, though the "keystream" is not necessarily secret. The main difference is that direct sequence is a wideband signal while, at any instant, a frequency hopped signal is still narrowband.

Each method has advantages. Frequency hopping can be especially resistant to strong narrowband jamming, so it's a favorite of military systems (Lamarr's intended use). Direct sequence is easier to use with coherent modulation so it tends to use transmitter power more efficiently, and it can often provide precise timing and positioning as a side benefit. Or, in the case of GPS, as its primary purpose.

While CDMA mobile phones were very important in the 1990s and 2000s, it is now being replaced with LTE (Long Term Evolution), which uses OFDM - Orthogonal Frequency Division Multiplexing. So do many other modern terrestrial digital communication systems including DSL, HD Radio, DVB-T (but not ATSC), WiFi and DRM (Digital Radio Mondiale).

Submission + - Busybox Deletes systemd Support

ewhac writes: On 22 October, in a very terse commit message, Busybox removed its support for the controversial 'systemd' system management framework. The commit was made by Denys Vlasenko, and passed unremarked on the Busybox mailing lists. Judging from the diffs, system log integration is the most obvious consequence of the change.

Comment Re:Why was package versioning left out? (Score 4, Insightful) 185

Because package versioning is not a language issue. It's a build issue, and should be part of your build system.

"But go get ... reaches out and..." Stop. go get isn't part of the Go langauge; it's the default Go build environment. And yes, it lacks many features you'd want in a so-called "professional" build system (whatever that means this week).

I get the impression that Go was perhaps intended to be used with repo, a tool principally used for managing the Android project, but also used elsewhere inside Google to manage large numbers of independent Git repositories. With repo, you establish a common branch or tag name across all the repositories that comprise your project, then "repo sync" to them. Poof! Build and version management. (Sorta.)

Comment No more tourist attraction (Score 1) 336

My guess is that the Metropolitan Police is far from gone from the area; they simply got tired of being an overt tourist attraction. The Ecuadorian Embassy is right around the corner from Harrod's and also the hotel where we stayed as tourists last summer. I got the definite impression that the police on duty were photographed a lot...

Comment *WIN-BATTERIES?!?* (Score 1) 42

Someone needs to punch this idea in the throat right now before it gets deployed anywhere.

Need I remind the membership of the decades-long clusterfsck resulting from so-called "Win-modems" whose codecs were moved from hardware into host software and to this day remain completely undocumented? Even people who put down hard cash for a WinModem driver found themselves left to twist in the wind when the 3.x kernel series came out (modems may be mostly obsolete, but FAXes aren't (yet)).

Now: Who would like to bet that the WinBattery interface will not significantly extend battery life over what we have now, remain completely undocumented (or trapped behind onerous licensing that forbids Open Source implementations), and leave Linux and *BSD users with systems with significantly shortened battery life because they can't control the power interface?

This is yet another naked attempt to bottle up critical system functionality behind a Microsoft-only wall (because apparently fscking everyone over with UEFI and (In-)Secure Boot wasn't enough).

Comment DO NOT WANT (Score 4, Interesting) 55

Let me see if I'm understanding this correctly.

You want me to install an invasive gaming client that delivers no actual game content to me, imposes a network lag on all input, does not allow me to run a zero-latency LAN gaming session, does not allow me to run my own public server for my friends... And your business model is to get me to pay for this degraded experience?

...Good luck.

Thus spake the master programmer: "Time for you to leave." -- Geoffrey James, "The Tao of Programming"