Answers to discussion topic questions in Unit 7

Please make sure you understand the answers before you attempt the practice quiz or unit test.  Many of these answers came from your fellow students.

1. Explain how a vacuum tube can act as a switching device.
   
   In its simplest form, a vacuum tube consists of a filament and a plate in a hard vacuum.  The filament (cathode) is the source of electrons and is similar to the filaments found in an incandescent light bulb.  When heated, electrons "boil" off the surface.  The plate (anode) can establish the flow of current if it is given a positive charge with respect to the filament.  That is, if the plate holds a positive charge, electrons flow from the filament to the plate.  Thus, the plate can switch on or off a flow of current.  In an improvement, another electrode called the "grid" (a bent wire or screen) was placed between the filament and plate.  This grid would act to control the current flow between filament and plate.  For example, if the grid has a positive charge, it would promote the flow of electrons to the plate (because this would promote electron motion away from the filament).  However, if the grid was charged negatively (with respect to the filament), it would repel electrons and dampen the filament/plate current.  Perhaps you can see how this vacuum tube acts as an ampler (as well as a switch).  The plate serves as the signal output.  Any varying signal on the grid is matched by a similar (but larger) signal on the plate.
    

All computers require some routine maintenance.  Offer ONE piece of advice you should follow to ensure that your computer will keep working, run with optimal performance, or avoid potential problems.  Please avoid posts dealing with intruder prevention (like virus protection) or avoiding SPAM which are covered in other topics (the Internet).   That is, limit the post to keeping the hardware healthy.

Back up all important data often (and keep a copy off your premises)
Use the system maintenance programs such as disk defragmenter (defrag), disk clean up, and system restore (make a restore point when your computer is healthy)
Dust can build up and block air flow around your CPU heat sink.  Keep this area clean.
Protect your system with a surge protector and unplug the computer during intense lightning storms.
Never shake, rattle, or roll your computer when the hard drive is accessing data.  The read/write heads can touch and damage the disk.

Hardware

1. 1. Moore's Law is a rule of thumb related to advancements in chip design.  What is this "law" and how well has it held up?
   
   Way back in 1965, Gordon Moore predicted the number of transistors would double every 2 years (he originally predicted every year).  This prediction held up remarkably well.  Every 18 months the number of transistors on a chip have doubled.  However, in a 2007 article, Moore predicted that this exponential growth would only last for another 15 years.  In 2015, Intel announced definitely the numbers to show that progress truly was slowing down. In the same year, Gordon Moore himself stated that he saw his Law dying within the decade. Advances in nanotechnology may help increase the rate again, but for now we are sitting at roughly 3 years per component doubling. 
    
2. 2. What is virtual memory?  Under what circumstances is it used?
   
   When conventional memory resources become tasked, the computer will use the hard drive as a last resort.  Access time to the hard drive is significantly slower than convention memory but in a pinch, the hard drive will serve as virtual memory for data with the lowest priority.
    
3. 3. Compare the best chips on the market by Intel and AMD.   What is the target audience for these chips?  That is, why would someone really need this chip?
   
   Since new chips come flying off the assembly line, it is easiest to provide these links:  Intel press releases and AMD press releases
   
   
   These chips use dual and quad processors on the same die.  However, this kind of speed is only required for PC gamers and video rendering.  If you are like most folks who use their computer for email, writing letters, and web surfing ... these new chips are a waste of your money.  For example, I could easily do most of my work for this class on a slow, ancient Pentium class processor.  I use my faster (Core-2) notebook for video production.
    
4. 4. Find an independent source that compares CPU sales from Intel vs. AMD.  Is the gap changing with time?
   
   This graph says it all.  Prior to 2006, things were looking good for AMD but after that .... Intel took the bull by the horns.  Intel's market lead is around 75% (which fluctuates from year to year but not by much). The gap narrowed slightly in 2018 with huge AMD sales.
   
   Note:  Smart phones are now so popular that companies like Qualcomm, Samsung, and Apple are making big headway in the CPU market.  Taking this into account, AMD has slipped down the list quite a bit.

Software

1. 1. What is the advantage of using drivers (software which tells the OS how to handle hardware)?
   
   When you purchase a computer peripheral (printer, scanner, etc), you usually have an install disk that loads drivers for that equipment.  In the "old days" (mid 80's), folks who wrote software had to worry about how that software would interact with systems that ran it.  They wrote software called "embedded drivers" which were part of the main program.  So if you ran Lotus 123 (for example), the Lotus program had to know how to handle every kind of printer on the market.  This was a very bad design because new printers hit the market and also because each software application had to spend lots of time and money making sure their software would print correctly.  To get around this problem, Microsoft Windows offered a way for software to interact with hardware using drivers.  These programs must meet Windows communication standards.  This got software writers off the hook because they were no longer responsible for that aspect of their product.  In addition, any software application could use the same driver to run the peripheral (printer).  Perhaps the best part of this design is its adaptability.  If there is a bug in the program, you can simply download an updated driver.
    
2. 2. Why wasn't Gary Kildall the richest person on the planet?  Give a one paragraph overview of his missed opportunity.  In your answer, explain the role Tim Paterson had in the story.
   
   When IBM wanted to introduce a PC (in the early 80's), they needed an operating system.  They went to Bill Gates who referred them to Gary Kildall.  Gary Kildall had just what IBM was looking for ... an OS which looked like DOS.  IBM tried to work a deal with him but found him very rude.  They went back to Bill Gates and he purchased a program written by Tim Paterson for $50,000.  This program was basically a rip-off of Gary Kildall's program - DOS.  Gates took this to IBM and it became the OS for their PC.  The rest is history.
    
3. 3. Sometimes software is so popular it compels people to buy computer systems just to use it.  What was the first of the "killer apps" (for killer applications) that hit the PC market?  Hint: The two people who wrote it did not patent the idea so someone else made a fortune under a different product name.
   
   VisiCalc was the first "killer app".  This was a spreadsheet program used by accountants and marketers for forecasting.  Since Dan Bricklin and Bob Frankston (the two authors) did not patent their idea, companies like Lotus 123 (and later MS Excel) made fortunes on the idea.
    
4. 4. What is "plug and play"?  How does the OS know how to run hardware with this tag?
   
   When you insert any device into your USB port (or some other bus), you would like it to work without having to load software or manually allocate system resources.  I remember purchasing peripherals (modems and such ) and loading software and moving jumper pins or flipping DIP switches ... and becoming very frustrated trying to make everything work properly.  There had to be a better way!  This is what "plug and play" is designed to do.  Let's suppose you just plugged a new flash memory card into your USB port.  How does your OS recognize it?   It all gets done with help from the Windows BIOS chip (known as the PnP Bios).  This sends out signals to all peripheral bus routes.  If something is plugged in, it requests some information from that device.  Each "plug and play" device has a chip with software encoded on it called an ID string which gets sent to the Windows PnP BIOS.  The manufacturer of the device has to make sure that the OS has the appropriate driver stored on the hard drive.  The OS then automatically configures the necessary drivers (or asks for a disk if it can't find any)  ... which then arranges lines of communications (bus resources) for that device.  This lets the OS know what the device is and how to talk to it. 

Storing Data

HDD vs. Flash Memory (and SSD) : Compare hard drive data storage against flash memory in terms of cost per MB and access time.

HDDs are slower than SDDs.  SDD typically have read/write speeds in the 500 MB/s range.  A typical Hard drive have average read speed of 128 MB/s and a write speed of 120 MB/s. However, while HDDs are slower, they are cheaper, too. The cost is about $.03 per gigabyte versus an average $.20 per gigabyte for SSDs.  (2018 source)

Another consideration is how long you can expect the device to last.  Flash storage will typically wear out after 100,000 write cycles.   Special file systems or firmware designs can mitigate this problem by spreading writes over the entire device, rather than rewriting files in place.  On the other hand, hard drives fail for a large number of reasons ... mainly because they have moving parts which can be damaged or wear out.  One study of 100,000 hard drives showed 1.7% died within the first year and 8.6% bit the dust within 3 years.

Future Optical storage devices?

A Magneto-Optical disks have been around for some time but mostly in Japan.  This technology uses a laser (instead of a read/write head) to change the magnetic state of a disk (like a standard hard disk).

A technology known as UDO (Ultra Density Optical) is a twist to current CD techniques.   This uses a blue laser to make a phase change to a crystalline material on a disk.  The blue light means you can place more data in a smaller space (like Blu-Ray).  This allows 60 GB of storage per disk.  Just like CD's come in write once and re-writable formats, so, too, does UDO.  More here.

Multilayer Approaches:

Background:  One of the reasons why there are only two layers of data on standard DVD's is the fact that you have to read through the top layer to get to the next one.  This creates "noise" and scattering that can interfere with accuracy.  If you were to add a third layer, the build up of noise would cause read/write errors.  The following technologies are attempts to solve this problem.

Fujifilm plans on introducing a 1 TB disk in 2015 which has 8 layers of recorded data.  They use a "two-photon absorption method" which uses two photons of light to generate heat in a very small area.  Read more here.

Digital Multilayer Disk (DMD) - formerly called Fluorescent Multilayer Discs (FMD)  - Instead of being limited to just two layers (due to interference, scattering, etc.) on conventional optical disks, the use of fluorescence may allow for up to 100 recording layers.  Russian scientists have found materials which exhibit fluorescent properties when excited by a (red) laser of a certain intensity.  Once it obtains these properties (becomes a "1"), the laser reads the data by exciting the material to emit a unique color.  A disk can hold 20 GB of data with the prospect of up to 100 GB.

A company named Mempile is in the process of developing a new kind of disc that can have up to 200 virtual layers!  The reason this is possible is that the disc is made of a mixture of materials and its called ePPMA.  The disc is a see-through yellow which is a very important aspect which allows the many layers to be read.  Reading and writing is done when laser light (of various intensities) produces photochemical changes to the disk itself.  They hope to put over 1 Terabyte on a single disk.  Links here and here.

Holographic Data Storage - It should be obvious that a hologram can store data.  The neat thing about this idea is you can stack multiple layers together and still access the data on each layer.  This makes holographic storage a 3 dimensional medium, - capable of storing a great deal of data in a small volume. We are talking about terabytes per disk!!!

Multiplexed Optical Data Storage (MODS) may be able to store 100-200 bits of information on a single pit.  The key is to use polarized laser light.  This is accomplished by making the storage medium sensitive to polarized light.  Read more here.

Another MODS approach is to design disks with asymmetric pits.  Using current technology a pit is just a pit.  This approach uses pits at 332 different angles which reflects the laser to different angles.  This encodes different information for each angle.  This encoding of information could fit a Terabyte of memory on a single disk.  Read more here.

Super-RENS (Super REsolution Near field Structure) - In an effort to reduce the physical size of the data bit on an optical disk, it was found that you can obtain resolutions which are beyond the current limits of the industry standards (blu ray).  A hemispherical lens is placed just over the recording layer which helps focus the laser beam to an even smaller area, providing a "super resolution" which, apparently,  has yet to be understood by the comments in this article.

OK ..  this isn't optical but sure needs to be added because it is soooooooo cool

Storing data on DNA.

Harvard researchers are able to store 5.5 petabits (700 terabytes) of data on a single gram of DNA. How it works. “ the researchers first translated written words or other data into a standard binary code of 0s and 1s, and then converted this to a trinary code of 0s, 1s, and 2s…… The researchers then rewrote that data as strings of DNA’s chemical bases: As, Gs, Cs, and Ts. At the storage density achieved, a single gram of DNA would hold 2.2 million gigabits of information, or about what you can store in 468,000 DVDs. What’s more, the researchers also added an error correction scheme, encoding the information multiple times, among other tricks, to ensure that it could be read back with 100% accuracy”. “Researchers claim the data could last over 10,000 years and can be read by anyone so long as they have access to a machine that can read DNA”. Now we can’t run out and purchase DNA drives right now, the technology needs to be standardized and the cost of $12,400 per megabyte is a bit cost prohibitive for mass use. Researchers hope with advances to the field and private companies developing cost effective options we may see the first DNA data storage devices in our lifetime.
 

... on the same topic

Professor V Renugopalakrishnan has claimed to develop a layer of protein that is made of genetically altered micro proteins that are able to store data . It is light activated and can store about 50 terabytes.  It captures and stores sunlight to convert it to chemical energy.  These disks will be able to hold 20 times more than Blue-Ray disks and predicted to hold about 50 terabytes.

http://www.technotactics.in/protein-coated-disk-an-evolution/

Computer Memory

1. 1. What was the Y2K problem?  In your answer explain what caused it.  Hint: It had something to do with the subject of this page.
   
   Early programmers abbreviated the year to two digits.  That is, the year 1963 was shortened to 63.  The problem was, when the century moved from 1999 to 2000 the computers would think the time was moved back to 1900.  Besides the inconvenience, it was thought that programs might crash as a result.  Programmers spent years trying to correct this problem but there was real apprehension that airplanes would crash when the time hit.  Note: I was on an airplane at the time and I remembering ordering a $5 beer ... just in case.  LAX was a ghost town when we landed.  Why was this allowed to happen?  In the early days RAM was so expensive that it was felt that you could conserve valuable resources by taking this short cut.
    
2. 2. Cache memory is subdivided into L1 and L2.  What is the primary difference between these two classifications?
   
   L1 is known as primary cache memory and is printed directly on the CPU.  Only the most frequently used and most important data is stored there (which is the most expensive real estate on the CPU).  The close physical proximity to the CPU becomes important because access to the CPU is restricted by the speed of light (which is fast but not infinite).
   
   L2 cache (secondary cache) has a slightly lower priority and is located close to but not necessarily on the CPU itself (but may be printed on the CPU as well).  L2 cache memory is typically larger but slower than L1 cache memory.
   
   Cache memory is expensive but fast.  This form (SRAM) uses 4 transistors to store a bit and 2 more transistors - one each for reading and writing.  It is volatile (meaning it goes to zero if the power is lost).

Are there any intriguing technologies that may replace conventional dynamic or static RAM?  You bet there is!  Any of the ideas below could be the future of computer memory.

3D XPoint - Intel and Micron have introduced a new type of non-volatile memory known as 3D XPoint (Cross Point).  The developers are very tight lipped about how it works but it does not use transistors and likely involves a phase change of a substance.  Each phase (crystalline or random state) offers a different amount of electrical resistively which is used to distinguish between a "0" and and a "1".

RRAM (Resistive random-access memory) - This non-volatile system saves data by altering the electrical resistance of a material sandwiched between two electrodes.  Current applied to the electrodes are able to "switch" the ionic state of the material to conform to one of two states of electrical resistance ... distinguishing between "0" and "1".

MELRAM (Magnetoelectric Ram) - A group has found a way to manipulate the spin of electrons to store data.  These MELRAM cells are made up of two magnetic alloys on top of each other that form a material whose spin orientation reacts to mechanical stress. This composite material is set on top of a piezoelectric substrate which provided the stress when an exterior voltage is supplied.

Nano-RAM or  NRAM - This a futuristic type of non-volatile memory which utilizes nanotechnology.   It could offer the non-volatility of flash memory, the speed of SRAM (cache) memory, and the density (lots of memory in a small space) of DRAM (capacitors & transistors).  It offers low power consumption as well as high durability.  It works using carbon nanotubes that rest over an electrode, which can be set in two possible positions - touching or separate (to distinguish between logical states "1" and "0") ... depending if a voltage is applied to the nano tube. This page gives a nice overview.  Here is a flash video.  This could be big!

RM (racetrack memory) stores bits of data as magnetized regions on "racetracks" on nanowires.  This is a nonvolatile memory with no moving parts except electrons to read and write bits.   The bits themselves zoom along their racetrack, passing a read/write head at a fixed location beside the wire.  More here.

ZRAM - This type of memory could replace traditional cache memory (SRAM) because it uses only one transistor (instead of 6) to hold a bit.  The "Z" refers to the fact that there is no capacitor (zero) to store the bit (which is used in DRAM).  It offers twice the space compression as DRAM and offers five times the density as SRAM.  It works using Silicon-on-Insulator transistors and the "floating-body effect", where capacitance develops between the body of the transistor and an insulating layer.  I'm sorry but you will have to tell me exactly how that works because I'm not a solid state engineer.  If interested, you can read more here.

STT-RAM (Spin-transfer torque RAM) - This memory exploits the "spin" on an electron that can only have one of two orientations - up or down.  As electrons move past nano-magnets, they acquire the same spin as the magnets.  This information holds the bit values "0" and "1".  The best part is this technology is non-volatile and extremely fast so you may have instant-on computers in the future.  If interested, this page has a great overview.

PCRAM (Phase change memory) - Certain substances (known as chalcogenide glass) are able to switch between a crystalline and non-crystalline state by the application of heat. This non-volatile form of memory may replace flash memory some day because it is 500-1000 times faster and uses half the power.

FRAM (Ferroelectric Random Access Memory) - In this type of non-volatile memory the alignment of a molecule is achieved by an external electric field. Once the external field is removed, the molecule retains its polarity to distinguish between "0" and "1". 

MRAM (Magneto-Resistive Random Access Memory) - It uses magnetic polarization rather than an electrical charge to hold a data bit.   In this type of memory, two magnetic substances are separated by a non magnetic layer.  One of the magnetic layers remains fixed in polarity.  However, the other layer changes its magnetic orientation based on an applied external magnetic field and thus, distinguishes the cells as either a "0" or a "1".  Reading is accomplished by passing a current through the cell.  In one state it offers little electrical resistance, but in the opposite state, the resistance changes to a higher value.  It only uses one transistor, is nonvolatile, has unlimited endurance, no refreshing is required, and it is better than Flash on write speed and durability.  It was sampled to customers in 2006 so this is fairly new technology.

Working with Bits

1. 1. Programmers often use another numbering system called hexadecimal (hex).  Briefly explain the base of this system, as well as the characters used to express numbers.  What is the reasoning behind this choice for counting? What is the hex value of 2989 (base 10)?
   
   Hexadecimal is a number system using 16 as a base.  It can make any number with the symbols 0-9 and A-F.  We use base 10 because we have 10 fingers.  By now you realize that computers use base 2 (binary).  This is great for computers but bad for humans.  Programmers knew that they needed a numbering system based on some power of 2.  Hexadecimal seemed to be the logical choice because computers had registers of 16 bit lengths.  With this system, you can identify the value in a 16 bit register with just 4 symbols (which offers 2^16 or 65,536 possibilities).  You can enter 2989 into the windows calculator (in scientific mode) and easily convert this to BAD in hexadecimal (a skill which will not be required on any test).  This page gives a nice overview.
    
2. 2. Calculate the disk space needed (in KB) to store a totally blank 24 bit Bitmap picture whose dimensions (attributes) are 100 x 100 pixels.   Show the calculations.  Would your answer change if the picture was filled with art?  Go to MS paint (or another readily available paint program) and make a picture with these properties.  What are the approximate dimensions in inches?   Save a totally blank image as a GIF image.  What is the file size?  Calculate the compression ratio.  Fill the image with some home drawn art and save.  Did the file size change?  Explain.
   
   In a 24 bit Bitmap image, each pixel needs 24 bits to store the color information.  This is equal to 3 bytes.  A 100x100 image requires 10,000 pixels.  Just multiply to get 3 x 10,000 = 30,000 bytes = 30 kb.  If you put colors into this image the size of the file would not change but the values stored in each bit would. The size of this image is very small .. only about 1¼" on a side (you can get this in MS Paint by choosing image, attributes).
   
   If you save the white bitmap image with a gif format (file, save as), the file is reduced to 1 kb.  This is a 30:1 compression.  If you put art into the picture, the file size will increase (depending on what you put in and how much contrast it contains).  However, the file size will very likely be much less than the 30 kb size of the bitmap image.
    

3. 3. Show how you can construct an XNOR gate using any combination of the gates introduced in this unit.

   As an aid, I've included the truth table for this gate:

   The XNOR table

   Input A	Input B	Output Value
   0	0	1
   1	0	0
   0	1	0
   1	1	1

   
   Making the XNOR gate is actually quite easy ... just look at the XOR gate truth table and turn everything around.  To do this, just add a NOT gate at the end (see image below).  If you want to get fancy, I've indicated two other versions below that do the same thing.
   
   
   Three ways to make the XNOR Gate
   
    

4. 4. Trace the following values through either full adder, showing clearly the values at each gate's input and output.
    

   A	B	CI (carry in)	CO (carry over)	Output
   1	0	0	0	1

As an aid, you can print a copy of the full adder here (or improved adder here)

Please make sure you can trace values through this (or any other) system of gates just like I've shown below.  You may have to do the same on the test.  The key is to apply the truth tables for each gate properly.  If you want some more practice, trace some input values through the XNOR gates printed above.

The Internet

1. 
    
2. 1. Compare DSL, and cable Internet access in terms of speed, cost and availability.  List some advantages and disadvantages of each choice.
   
   How you connect to the Internet is mainly a matter of cost, availability, reliability, tech support, and speed.  As you have read in the class material, there are many ways to gain Internet access but we will limit this topic to DSL, and cable.   There is no magic formula to help you make an correct decision but there are things you should know to help you make an informed decision.
   
   Cable: Download Speed is typically 1-100 Mbps and you get this through your local cable company.  The actual speed depends on how many people in your neighborhood are accessing the service at the same time (as well as other factors such as artificial caps imposed by your provider).  However, this is also the costliest choice.  For example, the normal charge for Time Warner is $35-$65 /month (depending on download speed you pick ... also they have a lower introductory offer).
   
   DSL:  The actual speed varies greatly between households, depending on the type of copper wiring used, type of computer and router but mostly how far you live from the central hub.  You may be able to obtain speeds up to 25 Mbps.  It is best if you call your provider to estimate the actual speed you can expect.  Each DSL provider also offers several plans with download times that vary.  You typically obtain access through your local phone company (since the signal comes through phone wires ... at a frequency with will also let you make phone calls).  You can expect to pay somewhere between $15-$30/month.  Speed for DSL is slowly catching up with cable thanks to two technologies - bonding and vectoring.  Bonding speeds things up by using multiple phone lines.  Vectoring (still in development) compensates for the noise and interference normally found in phone lines.  Vectoring may provide speeds around 100 Mbps (wow).
   
   BTW:  Anyone remember Dialup?   Squealing modems and watching the paint dry as something came in! 
3. 
   If interested, here are some interesting articles:  DSL vs. Cable  Speed Comparison
4.  

5. 2. If you live in a very remote location with no phone service or cable access, is it still possible for you to access the Internet?  If so, who provides this service and how much will it cost?

    Air cards (on laptop computers) and tethering to a cell phone are ways to access the Internet.  However, both need to be areas of local service to work.  However, satellite Internet service providers only ask you to have a clear view of the southern sky.  Exede, DishNET, and HughesNet are some providers of remote Internet.  Plans are based on access speeds and download limits but you can get your foot in the door for about $60/month

   
   3. What is the difference between a virus, worm, spyware, and a Trojan horse?  Give examples of the inconvenience each can cause.
   
   We all have to be careful to keep our computers systems isolated and the information on it private.  When you go online shopping, much of your activity is stored in cookies (a small file stored on your computer).  This way, the next time you go to amazon.com, they know who you are and what you have done on their sight.  For the most part, cookies are harmless.  Somewhat more intrusive is spyware.  This is a program designed to do any of the following:  track personal information, display unwanted pop-ups, add icons to your desktop, or change initial settings in your browser.  This code often enters your system when you download and install cheap or free software.  You can even pick this stuff up just by visiting the wrong web site ... called a "drive by".  The way around this is to make sure your security software (virus / firewall) program handles spyware as well and stay away from web sites that are "objectionable".
   
   A virus is a malicious program that attaches itself to an executable file.  It  behaves much like a real virus in that it tries to copy itself in hopes of infecting other systems. To activate it, a person needs to open it.  One common way a virus spreads is via attachments in email.  When you open the file, it infects your computer.  This can be a playful prank to downright nasty programs meant to damage your system or files.  To replicate itself, it can look up your email address book and send copies of itself to all your friends.
   
   A worm is much like a virus but does not require intervention by a person to replicate itself.  For example, it can cripple all computers in a network by exploiting security holes.
   
   A Trojan horse is a program (software) that is intended to do one thing but ends up doing something unintended.  A Trojan horse does not replicate.  How ironic.  Just as I was writing this, I launched a Trojan in a file mgrs.exe.  How it ended up on my computer is still a mystery.  My firewall caught this program asking for permission to the Internet.  Like an idiot, I let it through (thinking it was for windows messenger ... as the perpetrator intended).  A few $$$ later, I eradicated this dangerous "malware" program.  Here is a review of some software you can purchase ... just in case.  PS: This was NOT caught by my antivirus program.  I'm very fortunate I ceased all Internet activity as soon as I noticed new icons appearing on my desktop.
   
   If interested, click here to read more.

   4. Give one reason why your IP address probably changes every time you access the Internet (called dynamic IP address)?  Hint: It is partly to solve a problem the original developers of IP addresses didn't envision.

   Quite simply,  they are running out.  The format range is from 0:0:0:0 to 256:256:256:256  which gives just over 4 billion unique possibilities.  A new format called IPv6 will solve this problem because it is virtually limitless.
    

6. What is spam?  List things you should do to avoid it.
   
   Spam is unsolicited bulk email.  There have been many attempts to block spam and each time the spammers have found a way around the system.  For example, your ISP can go to spamhouse.org to get a list of IP addresses of known spammers and block them.  All they do is obtain another IP address and anyone who picks up the old IP automatically becomes blacklisted.  They can hijack your machine and make it a "spam zombie" so it looks like the spam came from YOUR machine.
   
   Rule #1 - Avoid printing your email address on web pages or in chats.  If you must, disguise it like johndoe AT someplace DOT com.  Your email program will likely have a spam filter.  If too much gets through, move it to a higher setting.  However, this may block some legitimate emails.  You can also set up "rules" to handle email.  For example, my email program sends email with common spam phrases directly to the trash.
7.  
8. Besides a firewall, spam protection, and virus protection, what other security steps should you take to avoid problems from Internet intruders?
   
   If you have a wireless network, make sure your router only gives access encrypted with a key.  WEP is an encryption tool on wireless networks designed to prevent introducers.  However, all you have to do is ask the folks at TJX just how secure that system is.  The short answer - not very.  A much better security standard is called WPA.  Use that standard if you have the option.  As an added layer of security, have your router only grant access to known computers on your network.  Each machine has a unique MAC address (at the command prompt type ipconfig /all to find it).  It is possible to have your router filter your home network to only include machines you want.  This is a sure-fire way to protect yourself from intruders.
   
   A common practice (called phishing) is an attempt to trick you into giving your personal information away.  It does this by mimicking an "official looking" email from a place you may do business.  You may be asked to give you social security number, credit card number, bank account and pin number, etc.  DON'T DO IT!
   
   If you shop online, make sure your browser is up-to-date and you send sensitive information over an encrypted site (a tiny lock appears).  The way this works is the site you go to sends you an encryption key and after that, all information is scrambled.  If you have a hard wired Internet connection it is virtually secured.  Even if you send this over wireless you can feel secure because any hacker would first have to intercept the encryption key and then use it.  Virtually impossible.  Make sure you have a secure wireless network at home.  Here is a great article that offers 10 tips to wireless security.
    
9.  
10. HTTP stands for hypertext transfer protocol.  It is the standard way most web pages are handled over the Internet, ... but not the only way.  Give one example of a different format for transferring data.  What are the advantages?  Give a brief overview and offer a way we can experience it first hand.
    
    Perhaps I'm dating myself but I remember the Internet before there were any web pages (http://).  Back then, you downloaded from a remote computer using FTP (file transfer protocol).  Do you remember gopher, and telnet?  Your email is now handled by a different format: SMTP (Simple Mail Transfer Protocol).  But let's not make this a history lesson, we should look to the future and concentrate on new innovations for the next generation of Internet users
    
    HTTPS://  (Hypertext Transfer Protocol over Secure Socket Layer) is now commonly used as a security option.  It is an attempt to encrypt any information you send or receive from that site.  Make sure your next online shopping spree is done securely.  Look for a small closed lock icon somewhere on the page and look for the HTTPS in the address bar.
    
    RTSP (Real-Time Streaming Protocol) is used to stream video and voice over the internet.  It is used in Skype and QuickTime, for example.
11. 
    ICMP (Internet Control Message Protocol) is used to "ping" a specific server ... basically to determine the speed of the connectivity between you and them.  It also can be used to trace the router paths to determine hop counts and other transfer information that can be used to detail where your data is going to any specific point.
     
12. XML (EXtensible Markup Language) is a protocol designed to transfer date over the Internet.  It is also much more "human friendly" to write in than HTML.   If interested, click here to read more.
13.  
14. UDP (User Datagram Protocol) is another type of data transfer.  We most often see it in streaming music and video, as it is designed specifically for fast, but unreliable, non-secure data transfer.  Meaning, you get most of what is sent, but not everything, and not all the time.  That's okay so long as the data being sent is trivial i.e. not your savings transfer to a bank.
    
    AJAX (Asynchronous JavaScript And XML) is a Google initiative that makes greater use of JavaScript over the Internet.  Specifically, it allows you to download tiny bits of information from a server rather than a whole page at once.  Just go to Yahoo maps and see how you can move the map around without refreshing the entire screen.