Preamble is still used in the very same way – the information at the head of a transmission contains information about the message that follows. If you examine a transmission of data on a garden-variety Ethernet network, you will find that each packet of data has a preamble with a unique number and address, among other things.
|“Just because you’ve got the best hammer in the entire world doesn’t make everything a nail. If you’ve got a screw, even a cheap, old, rusty screwdriver is going to do a better job. And MapReduce is a lot better than a cheap, old, rusty screwdriver.”
Mark C. Chu-Carroll, Databases are hammers; MapReduce is a screwdriver
RDBs are absolutely brilliant things. They’re amazing tools, which can be used to build amazing software. I’ve done a lot of work using RDBs, and without them, I wouldn’t have been able to do some of the work that I’m proudest of. I don’t want to cut down RDBs at all: they’re truly great. But not everything is a relational database, and not everything is naturally suited towards being treated as if it were relational. The criticisms of MapReduce all come down to: “But it’s not the way relational databases would do it!” – without every realizing that that’s the point. RDBs don’t parallelize very well: how many RDBs do you know that can efficiently split a task among 1,000 cheap computers? RDBs don’t handle non-tabular data well: RDBs are notorious for doing a poor job on recursive data structures. MapReduce isn’t intended to replace relational databases: it’s intended to provide a lightweight way of programming things so that they can run fast by running in parallel on a lot of machines. That’s all it was intended to do.
|“It’s perfectly legal to rip music from a CD and upload it onto an iPod for personal use; why can’t a person do the same with their own copies of movies?”
Brennon Slattery, Why Pick on RealDVD?
It’s sad that RealDVD, with its sophisticated and lawful approach to DVD-copying, had to swallow the wrath of the MPAA. It’s also clear that the DMCA [Digital Millenium Copyright Act of 1998] needs to be updated to reflect the changes in media distribution 11 years later.
|“…If I were to release a piece of software under the MIT License, and then give you a copy, you would be free to modify, sell, and build upon my creation so long as you leave the notice that I was the source of the original work in your adaptation. Licenses like the MIT License and Creative Commons licenses enable me to hold credit for my work while still giving my consumers some freedoms.”
Winslow Dalpe, Why Go Open Source?
Today’s WhatIs.com Word of the Day is MIT license.
||“The two biggest differences between the CDMA and GSM standards are international compatibility and how the networks handle activating phones.”
Adama D. Brown, Brighthand FAQ: What’s the difference between CDMA and GSM?
Outside the U.S. and Canada, most GSM phones will still work, while almost all CDMA phones simply can’t be used overseas.
CDMA phones are activated remotely, by the carrier, using the phone’s serial number, known as the ESN. Since each carrier has a database of all the ESNs that are approved for its network, this lets most CDMA carriers refuse to activate phones not originally intended for their network.
GSM phones are activated differently. Each account is associated with what’s called a SIM card, or Subscriber Identity Module. This card, about the size of a fingertip and the thickness of a piece of paperboard, carries an encrypted version of all the information needed to identify your wireless account to the network. You slip it into the appropriate slot on a GSM phone (usually under the battery) and that phone is ready to use.
|Pushing fiber close to the customer is generically called “deep fiber,” and various acronyms are used to indicate just how deep the fiber is. FTTH means “fiber to the home,” which is the extreme of giving every user an optical-electrical termination. FTTC takes “fiber to the curb,” serving a group of homes, while FTTN means “fiber to the node” or “neighborhood.”
Tom Nolle, Fiber-optic networks: Access network design
Operator studies suggest that the migratory WiMAX model is most valuable in cities with large student populations, areas where mass transit is used for commuting in preference to private automobiles, and areas where online video usage has been well-socialized among wireline broadband users.
Where there is a strong wireline content appetite, sustaining that appetite in other places where the user may relax is far easier. On the other hand, in locations where much of the population commutes by car, where the user is older and less likely to view content online at home, and where a large segment of the population of a service area may be moving in from a different area, the mobile-evolution or LTE model is easiest to validate.
|The ongoing economic downturn is fostering a changing of the guard in telecommunications services. What might look like a business depression is actually providing fertile ground for a shift in technology. It’s traditional TDM switched circuits out. IP based Ethernet connections in.
John Shepler, Ethernet Takes Over, Mbps Prices Fall
HSPA is a general name for the High-Speed Downlink Packet Access (HSDPA) and High-Speek Uplink Packet Access protocols. They are packet-based mobile telephony protocols used in 3G to increase data capacity and speed up transfer rates. One of the primary differences between HSPA and EV-DO networks is that HSPA allows mobile handsets to transmit voice and data simultaneously.
Jonathan Morgan has written a very interesting post explaining why HSPA is so important. It all comes down to dollars.