Best of Tech Talk taken from previous shows Email from Listeners Profiles in IT od Science -- Mother Sauces Profiles in IT #2: Steven J. Sasson Anchor Charged with Hacking Colleague Email Physics of Whipped Cream
Details of the previously recorded segments are shown below.
Email from Listeners
Email from Lauren: Dear Dr. Shurtz, I have 2 TVs in my house. One is a Sony Bravia I bought in Jan. 2009. It has a VHF/UHF antenna attached and gets. 4.1, 4.2, 4.3, 5.1, 7.1, 7.2, 7.3, 9.1, 9.2, etc.–about 13-19 channels. Today, I got no signal on it for channels 26.1, 26.2, 26.3, or 26.4 though those channels had been working fine before today…Also, today, Sat, I was watching something on Channel 32.1 and at the end of the program there was this ‘statement’ that said I need to re-scan my TV if I don’t have a cable or pay for TV. I’m not following what this need to do periodic re-scanning is all about and how often I am to do this? The Bravia is new and has a built in DTV tuner. Thanks, Lauren B.
Tech Talk Answers: Prior to the switch to all digital, some stations had their digital and analog channels split (one in UHF and one in VHF). When the analog transmission was discontinued, some switched the digital signal to the same frequency as their analog signal. In that case, you will need to rescan your system to detect the new digital frequency. This only needs to be done once.
Email from Ken: Dear Dr. Shurtz, my computer with Windows XP has many files and folders that are corrupted, including C:$Event$ObjId and $Mft, which I get error messages about repeatedly. Many files that are supposedly corrupt can be seen in Windows Explorer, and most can be opened and used, but they can’t be deleted or moved. Will Spinrite repair the corrupted files, or is there another utility that will? Thank you. Ken, Gaithersburg, MD
Tech Talk Answers: I have good news. Microsoft XP has a utility to fix corrupted files. It is called System File Checker, with a file name of sfc.exe.
Place your Windows XP CD in CD/DVD drive, and verify that the computer recognizes it.
Point and click your "Start" menu, and select "Run." A box will appear that will prompt you for a command.
In the box that appears, type in: sfc /scannow The fix will now load, and will hopefully fix all of the corrupted files on your Windows XP drive.
You could also attempt a defragment of your hard drive, as fragmentations of files can sometimes reduce errors. You might also run spinrite in the event that you have physical corruptions of your hard drive.
Email from Jim: Dear Tech Talk, I have a vacation home on Lake LenLanau in Michigan. I cannot get cell phone reception in the house. However, I can get weak reception if walk behind the house toward the road. Is there anything that I can do to improved my reception. I am using AT&T.Ranges extender for cell phone???for vacation home on the lake. Thanks, Jim
Tech Talk Answers: You can buy a cell phone booster which will amplify the weak signal and retransmit it within your house.
I recommend that zBoost YX510-PCS-CEL Dual Band Kit. It will handle all service providers (both CDMA and GSM) and operates in the 800 and 1900 MHz bands.
Compatible with all networks (except Nextel)
Supports up to 20 users simultaneously with no need to connect to your phone to improve reception.
Improves standard CDMA and GSM voice signals, and also EVDO, HSDPA, UMTS, and EDGE data transfers.
Approximate coverage are is 2,500 sq ft.
External Omni-directional Antenna (5db) with 35 ft of RG-6 coaxial cable
Internal base unit antenna (2 db)
List price: $349
Profiles in IT
Linus Torvalds, Developer of Linux
Linus Torvalds was born on December 28, 1969 in Helsinki, Finland.
Named after Linus Pauling (winner of Noble Prize in Chemistry). Torvalds later claimed to have been named after the blanket carrying, Linus, in Peanuts.
His parents were communist radicals and other children used to tease Linus about it.
His grandfather bought him a Commodore VIC 20, one of the first personal computers, and Linus learned to write computer games for it when he was twelve.
In 1988, Linus began studying computer science at the University of Helsinki. He invested in a better computer with a 386 processor and began learning the assembly language for the processor. He coded a number of advanced software projects, including a floppy disk driver and software assembler.
In 1990, he began learning Unix when the university purchased a MicroVAX system.
UNIX was common on huge computers with many users, but it was bulky, expensive, and impractical for personal computers.
Torvalds had a PC that came MS-DOS. He installed Minix, a PC-compatible mini-mimic of UNIX, but he wanted something more flexible and user-friendly.
In 1991 Torvalds spent several months writing a compact operating system for his PC.
He almost called it Freax, but later decided on Linux.
He posted an announcement to the Minix group on USENET, and made the Linux source code available to other nerds free of charge.
Programmers everywhere started adding their own improvements
Eventually companies like Red Hat, Corel, Caldera, and TurboLinux began selling their own versions of Linux.
Linux quickly became a symbol of the open source movement, with a tuxedo penguin as its mascot.
Torvalds earned his masters degree in computer science at the University of Helsinki.
To handle Linux matters, Linus created the Linux Foundation, a non-profit corporation that holds the trademark name Linux.
In 2004 he was named one of the world’s most influential people by Time Magazine.
At this point, he has actually written about 2% of the kernel.
Food Science — Mother Sauces
Culinary Moves from Italy to France
Culinary tradition moved from Italy to France in the 16th century.
Catherine de Medici, niece of the Magnificent, took a multitude of cooks and their helpers to Paris when she married, at age 14, Henry of Orleans, the future Henry II in 1533.
The five mother sauces as designated by Escoffier were bechamel, veloute, hollandaise, espagnole, and tomato.
Béchamel, the classic white sauce, was named after its inventor, Louis XIV’s steward Louis de Béchamel. The king of all sauces, it is often referred to as a cream sauce because of its appearance and is probably used most frequently in all types of dishes. Made by stirring milk into a butter-flour roux, the thickness of the sauce depends on the proportion of flour and butter to milk.
Velouté is a stock-based white sauce. It can be made from chicken, veal or fish stock. Enrichments such as egg yolks or cream are sometimes also added.
Espagnole, or brown sauce, is traditionally made of a rich meat stock, a mirepoix of browned vegetables (most often a mixture of diced onion, carrots and celery), a nicely browned roux, herbs and sometimes tomato paste.
Hollandaise is made with an emulsion of egg yolks and fat. Hollandaise is made with butter, egg yolks and lemon juice, usually in a double boiler to prevent overheating, and served warm. It’s also used as the base for such mixtures as Tartar Sauce, Thousand Island Dressing, Aïoli, and Remoulade.
Tomato. This is self-explanatory.
Vinagrette. Sometimes this sixth one is added to the list. Vinagrette is a sauce made of a simple blend of oil, vinegar, salt and pepper (usually 3 parts oil to 1 part vinegar).
Profiles in IT #2: Steven J. Sasson
Steven J. Sasson is the inventor of the digital camera.
He was born in 1950 and grew up in Brooklyn, N.Y.
He received BS in 1972 and MS in 1973 from Renssalear Polytechnic Institute in electrical engineering.
His invention began in 1975 with a very broad assignment from his supervisor at Eastman Kodak Company, Gareth A. Lloyd.
Could a camera be built using solid state electronics, solid state imagers, an electronic sensor known as a charge coupled device (CCD) that gathers optical information?
The conversation lasted 30 seconds.
Texas Instruments Inc. had designed an electronic camera in 1972 that was filmless but not digital, using instead analog electronics.
After a literature search on digital imaging came up virtually empty, Sasson drew on whatever was available,
Analog-to-digital converter adapted from Motorola Inc. components
Kodak movie-camera lens
CCD chips manufactured by Fairchild Semiconductor.
He set about constructing the digital circuitry from scratch, using oscilloscope measurements as a guide. There were no images to look at until the entire prototype was assembled.
The first image of a female lab technician was recorded in December 1975
The camera had the following specifications
Weighed 8 pounds and was the size of a toaster.
Black and white image
Resolution of .0l Mpixels (10,000 pixels)
Time to record image was 23 seconds
Recording medium was digital cassette tape
Television for image display
In 1978, Sasson and Lloyd were issued United States Patent 4,131,919 for their digital camera.
Unfortunately, Kodak did not move quickly enough because it was still trying to milk its lucrative film market.
Kodak it let its Japanese rivals drive the digital-camera market. Sony produced the first digital camera in 1981 (Mavica)
Kodak’s first consumer camera was launched in 1994 under the name of Apple Quick Take, which was introduced in association with Apple Computers.
Kodak began selling mass-market digital cameras in 2001.
Kodak took the lead in US digital camera sales in 2004 (surpassing Sony and Canon).
Kodak has amassed more than 1,000 digital-imaging patents. Today, almost all digital cameras rely on those patents.
Sasson now works to protect the intellectual capital of his employer, Eastman Kodak.
His prototype formed the root of historical arguments against Sony in an patent-infringement trial over Kodak’s digital-camera inventions from 1987 to 2003.
Anchor Charged with Hacking Colleague Email
Former Philadelphia news anchor Larry Mendte on Monday was charged with hacking into the e-mail accounts of Alycia Lane, his co-anchor at CBS affiliate KYW-TV and reported rival, hundreds of times over the course of two years.
Mendte accessed Lane’s e-mail without authorization approximately 537 times, from KYW and from his home, according to the government.
A hearing has been scheduled for Aug. 22 at which Mendte is expected to enter a plea. He faces up to six months in prison if found guilty.
He either guessed her passwords, looked over her shoulder, or used a keystroke logger.
USB Keyloggers go between the keyboard and the computer and capture all keystrokes. Cost approximately $150.00. Other options are software based and can send keystroke data to another computer via the Internet.
Physics of Whipped Cream
Notice the interesting behavior of whipped cream
First it flows smoothly out of the nozzle like a liquid.
Then, a moment later, it perched rigidly in the spoon as if it were solid.
What made it change?
Whipped cream performs this rapid changing act because of a phenomenon called "shear thinning."
When part of the foam is forced to slide or "shear" past the rest of the foam, the foam "thins."
It becomes less like honey and more like water, allowing it to flow easily until the shearing stops.
Shear thinning occurs in many substances–e.g., ketchup, blood, motor oil, paint, liquid polymers such as molten plastic.
Excessive shear thinning of motor oil is unwanted because it reduces the oil’s ability to protect engines from wear,
Shear thinning of paint allows it to flow smoothly from the brush but stay put on the wall.
It also allows ketchup to flow from the bottle but not drip off your french fries.
The inner workings of shear thinning are not fully understood.