Pentium or Athlon processor?
Which one is best for my needs?
I don't play many video games
Should I get a high performance video card?
I know my PC has an IP address
What is an IP Address?
How do I get good sound from my PC?
Do I need a Sound Card?
PC Ports
What are they?
PC Monitor
CRT or LCD type?
DRAM Memory
Which type and how much do I need?
CD or DVD Drive?
Which one is right for me?
Which one is best for my needs?
I don't play many video games
Should I get a high performance video card?
I know my PC has an IP address
What is an IP Address?
How do I get good sound from my PC?
Do I need a Sound Card?
PC Ports
What are they?
PC Monitor
CRT or LCD type?
DRAM Memory
Which type and how much do I need?
CD or DVD Drive?
Which one is right for me?
My Hard drive
How big does it need to be?
Surge Protectors
Protect your PC from damaging voltage transients that sneak in on power and phone lines.
Wireless Mouse and Keyboard
They are quickly replacing their wired cousins.
What is a DLL file?
The Dynamic Link Library is a program used in Windows.
What is Ethernet?
One of the protocols used at to carry data in computer-to-computer communication.
Filenames and Filetypes
The basics of file naming conventions for DOS and Windows are covered.
What is a Modem?
This nifty device allows your PC to send and receive data over telephone lines.
How big does it need to be?
Surge Protectors
Protect your PC from damaging voltage transients that sneak in on power and phone lines.
Wireless Mouse and Keyboard
They are quickly replacing their wired cousins.
What is a DLL file?
The Dynamic Link Library is a program used in Windows.
What is Ethernet?
One of the protocols used at to carry data in computer-
The basics of file naming conventions for DOS and Windows are covered.
What is a Modem?
This nifty device allows your PC to send and receive data over telephone lines.
The central processor unit (CPU), often called just the 'processor', is the heart of the PC. It controls everything that happens in the computer, but its overall performance is determined by a couple of factors. The first is clock speed which is measured in Ghz (billions of clock cycles per second). The second is the size of the L2 cache that the processor uses.
L2 cache is a special memory that the processor uses frequently. It is located less than an inch or so from the processor. It is a very fast memory and shares data with the processor on a private connection known as the back side bus.
Faster clock speeds and bigger L2 caches translate into higher performance. The Intel Pentium class of processors are the most popular type found in PCs, and are offered in a couple of versions:
The Celeron is an entry level processor. It is really a Pentium 4 that runs at a slower clock speed and uses a smaller L2 cache. A smaller L2 cache guarantees more overall cache misses which results in lower performance.
A Pentium 4 runs at it's full rated speed and uses a large L2 cache.
AMD makes processors that directly compete with Intel, see below.
Recommendation:
The chief competitor for Intel is AMD (Advanced Micro Devices). They make the Athlon processor which competes with the Pentium 4 and the Duron which competes with the Celeron.
If you want to surf the web, send and receive e-
For those who want to run high performance applications that require serious number crunching and fast graphics, then a Pentium 4 or Athlon processor running at or above 2Ghz is the way to go.
We've used AMD and Intel processors and both are excellent processors. You can't go wrong with either one.
All PCs require special circuitry that is used to make the text and graphics images that you see on your display.
Most new PCs are equipped with motherboards that have integrated video chip sets in them. These integrated chips compete with other devices in the PC for access to the main memory . This causes congestion and slowdown.
A solution to this congestion is the Advanced Graphics Port (AGP) found on modern motherboards. It provides a place for a video card to plug in to the motherboard giving it a fast, clear path to the RAM main memory. Besides the fast path to RAM, the video card also has its own local memory anywhere in size from 32Mb to 128Mb which it uses to hold and manipulate the video data before sending it to the display.
Newer video cards also have a DVI connector which provides digital video signals that directly drive LCD displays equipped with a DVI connector. This type of connection provides very good looking video, but keep in mind that not all LCD displays have DVI connectors to take advantage of it.
Fast moving 3D graphics writes millions of bytes per second to the display and high performance video cards are key to realistic looking video. Running high demand video applications without one can make your display look like one of those jerky frame-
For general, everyday PC operation, the integrated video chips should work adequately.
If you want to run intense applications or video games that require fast, rich graphics, then you'll need a high performance video card. Radeon video cards from ATI and GeForce cards from nVidia are among the top brands offered
IPv4 stands for Internet Protocol version 4. It is the original standard set up for handling IP addresses when the Internet was initial developed by DARPA (Defense Advanced Research Projects Agency) in the early 1970s.
IPv4 uses a 32 bit address field which provides for 4,294,967,296 unique Internet addresses. This is the number of computers/devices that can be connected to and use the Internet. In the early 1970's the population of the earth was less than 4 billion people, personal computers did not exist, and at most there were hundreds, perhaps thousands of mainframe and mini computers that had been assigned Internet addresses. So the 4 billion plus address space was deemed to be more than enough to last beyond any foreseeable requirements.
IPv4 addresses are all but consumed
By 1992, the rapid explosion of the Internet fueled by the vast number of personal computers attaching to it, made it clear that the IPv4 address space was already consumed to the point that a replacement had to be found.
IPv6 was developed in response to this situation. IPv6 allocates 128 bits to map the Internet address space. The number of bits were not just doubled, but instead quadrupled from IPv4's 32 bits to insure that this address space would not run out any time soon!
IPv6 addresses will probably never run out
128 address bits provide IPv6 with 340,282,366,920,938,463,463,374,607,431,768,211,456 unique addresses. It may seem like overkill to have this many addresses available, However, many visionary individuals believe that eventually every wired and wireless computer, cell phone, PDA, household appliance, security camera, devices that haven't yet been invented, will each have their own unique Internet address.
Besides the huge number of IP addresses, IPv6 provides for better handling of voice than IPv4 which was not initially set up to handle it. This means that phone conversations over the Internet will be smooth and clear instead of choppy and broken up like they often are now.
The time is almost upon us when any device with an Internet address and a connection to the Internet can be monitored and controlled from anywhere in the world. While you're away on vacation you could turn on lights, change your thermostat, check security cameras around your home, etc. The possibilities are only limited by our imagination!
As the PC has evolved from a plain computer to an entertainment center, the sound quality it produces has become an important consideration.
Most PCs come equipped with motherboards that have integrated sound chips that provide connectors for speakers, a headphone and line-in. Having an integrated sound card means that a separate sound card is not required.
A set of speakers is also part of the standard PC package. They can be the stand-alone type or the type that are integrated into the sides of your monitor. They are usually of low to mid grade quality.
Recommendation:
For everyday use the standard set up described above is sufficient.
If you're an audiophile, a music producer or a game player who wants the latest surround sound effects, then a Sound Blaster card from Creative Labs or a Turtle Beach card from SantaCruz is what you would install in your PC.
When combined with a good set of speakers your PC can create very high quality audio. Logitech, Creative Labs and Altec Lansing make speakers designed for PCs.
To add a full, rich bass sound get a three-speaker system that includes a woofer speaker along with the left and right stereo speakers. If you want to use your PC to watch movies then go with a five-speaker system that provides full, home theater surround sound.
Most PCs come equipped with motherboards that have integrated sound chips that provide connectors for speakers, a headphone and line-
A set of speakers is also part of the standard PC package. They can be the stand-
For everyday use the standard set up described above is sufficient.
If you're an audiophile, a music producer or a game player who wants the latest surround sound effects, then a Sound Blaster card from Creative Labs or a Turtle Beach card from SantaCruz is what you would install in your PC.
When combined with a good set of speakers your PC can create very high quality audio. Logitech, Creative Labs and Altec Lansing make speakers designed for PCs.
To add a full, rich bass sound get a three-
Ports are pathways that connect your PC to external devices, or peripherals as they are called. Up until recently they were always located at the back of the PC. They are now often found on the front of it as well.
USB
USB (Universal Serial Bus) has become one of the most popular ports found on a PC. All new PCs have at least 2 USB ports. Printers, scanners, and many other peripheral products have USB ports which makes it very easy to connect them to your PC.
USB is very user friendly and supports what is called Plug'n'Play. This means that when you connect a device to your PC with USB, it is automatically detected and set up without your intervention. In some cases, you may have to install a device driver provided by the manufacturer on a CD or on their web site.
USB is available in a couple of standards. USB 2.0 is the fastest at 480Mbps (million bits per second). The earlier USB 1.1 runs at 12Mbps.
Firewire
Firewire is another type of port found on newer PCs. It is also known as i.LINK or IEEE 1394 and is rated at 400Mbps which puts it in the same speed class as USB 2.0.
When Firewire first came out, only USB 1.1 was available and many observers thought it would push USB out of the picture. With the advent of USB 2.0 and it's proliferation into so many peripheral devices, USB is here to stay.
Flash Card
Many new PCs provide ports for reading and writing flash cards. This allows you to access data directly from the flash card without having to connect your digital camera or PDA.
Recently I saw a new PC from HP that had a port with multiple slots for connection to many flash card types: Compact Flash I/II, SmartMedia, Memory Stick/Pro, MultiMediaCard and Secure Digital.
If you use a PDA or digital camera this type of port comes in very handy.
Legacy ports
Most PCs still have parallel, serial or game ports. These ports are always put on the back of the newer PCs and will eventually be phased out.
Recommendation:
Buy peripheral products that use a USB port. Why? Every PC produced in the last few years has at least 2 USB ports on it. This makes it a given that most devices can connect to a PC and run right away. Most camcorders, however, connect to the PC through a Firewire port.
Make sure you know what USB standard your PC supports. It may only support the older USB 1.1 type.
If you want to connect more than two USB devices to your PC, where would the third one plug in? The solution is provided by a device called a USB Hub. It plugs into one of the PC's USB ports and allows from 4 to 8 USB devices to plug into it. The ability to quickly scale up and connect to multiple devices combined with the fact that almost every peripheral has one makes USB the port of choice.
If you have devices that use flash cards, then a PC equipped with ports that can read and write them is quite useful. If the PC doesn't have this type of port built in don't worry, you can connect an external flash card adapter to your PC later on using -
If you work at a PC often, then you don't want to skimp on a monitor because your eyes will tire more quickly from looking at anything but crisp, clear text and graphics.
Up until a few years ago the only monitors commercially available were the CRT type. They take up a lot of desk space and are fairly heavy. Recently LCD displays have become available. They are flat, take up very little desk space and are much lighter than CRT types.
LCD units cost about £150 more than similar sized CRTs. The appearance DVI connectors on some LCD monitors allows it take advantage of digital video signals delivered by newer video cards. Before DVI all video signals in the PC were analog. This new feature has given the LCD display equal or better viewing characteristics than the old, venerable CRT.
Recommendation:
The differences in cost and space required between the CRT and LCD monitor may be the factors that swing you one way or the other.
However, the way text and graphics appear is a much more subjective characteristic. Before you buy, it is worth seeing both types of display set up side-
Your PCs main memory is called by a number of names: RAM, DRAM, SRDRAM, DDR SDRAM. Don't be confused by these names. They are all types of RAM (Random Access Memory).
PCs first used DRAM (Dynamic Random Access Memory) for main memory. These were improved and became SRDAM (Synchrounous DRAM). The latest version is a DDR SDRAM which is a (Double Data Rate SRDAM). It runs twice as fast as SDRAM.
Main memory is used to store programs and data electronically when your PC is running. It communicates with the processor over the front side bus. Memory capacity is measured in megabytes Mb (millions of bytes).
A big memory allows your PC to run multiple programs with out slowing down and with much less of a chance of crashing. Your memory also needs to be fast and manufacturers offer it in a number of speed grades.
Multiple memory chips are packaged together on a small circuit board. This assembly is called a DIMM (Dual Inline Memory Module). DIMMs plug into the motherboard. SDRAM and DDR SDRAM memory chips are still found in DIMMS, but the SDRAM chip have pretty much been replaced by the much faster DDR SDRAM chips.
Recommendation:
Get at least 128Mb of DDR SDRAM at a speed grade of PC2100. Make sure your PC motherboard has sockets that accept DDR DIMMS and a memory controller capable of running PC2100 memory. Any new PC motherboard should be able to support these requirements.
SDRAM DIMMs are still available in the after market. They have 168 pins and require a socket different than that used by the 184 pin DDR DIMM.
Some motherboards have both types of sockets that allow you to use either type of DIMM. You can't use both types of DIMM together. It's all one or all the other.
CD and DVD drives are optical storage devices that use lasers to read and write data on disks. All PCs today come with a CD, DVD or combination drive (works with CD and DVD). Most newer PCs have a combination drive installed that can read and write CD and read DVD. This type of drive is called a CD R/W-
PC manufacturers may offer a PC that comes with just a CD R/W drive or a DVD-
If you want to create your own movies you'll need a DVD-
At a minimum, get a combination drive that can read and write CD and read DVD. This gives you a great deal of flexibility. You will be able to store and listen to music files, watch movies, and backup all your data on CD using a drive that costs about £50.
For about £100 you can get a drive that can read and write CD and DVD. This provides all the features of the £50 drive and adds the capability for you to make your own movies!
Hard Disk size is measured in gigabytes Gb (billions of bytes) and like everything else in the PC world continues to increase in size. 200Gb drives are readily available.
The PC-
There are a couple of factors that govern hard drive performance
Access time can best be explained by thinking of a record turntable. When you play a record on one of these, you place the tone arm down on the track you want by lifting the arm, moving it over the track, and then gently setting it down, right?
On a hard drive there are magnetic platters that spin around at 5400 or 7200 RPM. Over each platter is a read/write head that can move back and forth across the platter like the tone arm of the turntable. The difference is the read/write head never touches the surface. When they do it is not by design and is called a head crash which ruins the hard drive!
When your PC wants to get a file from your hard drive, the read/write head has to move to the track that contains the file. The time it takes to get from where it is to the track is called access time.
Once it is over the track it begins reading data from the track. The rate at which it transfers data from the track to the PC is called the data transfer rate.
Access time is dependent on the RPM of the hard drive and the data transfer rate is dependent on the electronics that actually read the data from the platter.
Besides those two factors, fragmentation comes into play. Why, because a file that is in fragments means the read/write head is constantly jumping from fragment to fragment, which takes time, rather than coming down and reading the file from one big continuous section!
Recommendation:
For general-
This why saving your work frequently is very important. Until you do, all your changes/updates are only in memory, not on the hard drive. I save changes often with a quick 'alt-
For reference, 200 MP3 files take up about 1Gb of space. 1500 digital pictures in low compression jpg format also take up about 1Gb.
If you want to store 'lots' of digital files like audio, video and photos, then a 80Gb-
In either case, look for a drive that will support ATA-
This is an area that is critical to the continued operation of your PC. Power surges and lightning strikes can sometimes get coupled into your PC through the power line or phone line. These surges can and often do damage PCs.
Surge protected power strips have snubber circuits that filter out these potentially dangerous power line transients.
The AC line protection feature is easy to use.
Plug the surge strip into any working AC receptacle.
Then plug your PC into one of the receptacles on the strip that is protected. Usually they all are, but read the markings on the face of the strip to be sure.
In addition to AC line protection many surge protectors also have protected phone line connectors. Use these to protect your PC's modem:
Plug a standard telephone cable between the phone wall connector and the 'In' connector on the surge protector.
Use a second telephone cable to connect your PC's modem to the 'Out' connector.
Your modem and PC are now protected from dangerous phone line transients.
Surge protectors with these features cost around £15 and are well worth every penny!
Surge protectors with these features cost around £15 and are well worth every penny!
Wireless Mouse
The wireless mouse has scurried onto the scene in recent years. It's primary benefit is not having to drag around the wire that connects it to your PC. Instead it communicates with Infrared light (IR) or radio waves (RF) to a pod that is connected to your PC's PS/2 or USB port.
Infrared Type
The first wireless mouse used Infrared light to communicate with the pod. This is the same technology that is used in your TV remote controller, and as you know the distance between controller and TV can be many feet apart. The mouse and pod have the same long distance range. The major drawback is when something gets between the controller and the TV, it doesn't work. The IR mouse has the same drawback, it must have a direct line-
The next type of wireless mouse to show up was the RF mouse. It uses the same technology as in your car remote lock controller. As with the car lock controller the mouse does not need line-
In addition to the wireless communication between mouse and pod, just about all wireless mice use optical means to convert the back and forth, side-
They use the same IR or RF technology as the wireless mouse to communicate with a pod. You can often buy a wireless mouse and wireless keyboard set that communicates with a single pod that connects to your PC.
Ethernet is the most widely-
At first a data rate of 10Mbit/sec (million bits per second) was carried between PCs connected together by one or two coax cabling systems:
|
·
|
10base2 (thin coax) carried data about 185 meters before a repeater was needed.
|
|
·
|
10base5 (thick coax) could carry data a maximum of 500 meters without a repeater.
|
10baseT (twisted pair cable) appeared later and carried data 100 meters without a repeater. Today it is the most widely deployed cabling system used in LANs.
Data Collisions
Ethernet uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) to maintain the orderly flow of messages on the network. In CSMA/CD, each PC listens to the line. If the line is quiet any PC can begin transmitting.
Since any PC can transmit when the line is quiet, two will inevitably start transmitting at or near the same time. The messages collide and the result is that neither message gets through.
When a collision is detected, all PCs must back off and wait a random amount of time before transmitting any new messages. If one device keeps transmitting for whatever reason, the network gets tied up and no one else can use it!
Ethernet Hub
Eventually the hub was developed. It can connect a small number of PCs together in a star formation. Think of spokes of a wheel all connected to the hub at the center. The hub monitors each PC connected to it and disconnects any PC that violates the CSMA/CD rule.
It was a great improvement over the serial, daisy-
It also eliminated the problems that often occurred when one PC failed electronically, or was improperly disconnected from the coax cable.
If one PC failed in a certain way, it could disable the entire network.
If the coax cable at one PC was improperly connected, it split the network into two, isolated networks on either side of it. PCs in one network could no longer talk to PCs in the other network
Switches interconnect LANs and transfer messages between them. The development of switches allowed the size of networks using Ethernet to become larger.
Without switches the size of an Ethernet system is limited. The reason for this is that computers at opposite ends of a large network are too far apart to follow the CSMA/CD protocol required for orderly traffic flow.
Collisions let each transmitting PC know that its message didn't get through. When PCs are too far apart they don't know about collisions that may be happening to their message at the far end of the network due to the very long back and forth time delays. Since they don't know their message collided and failed, they never retransmit it!
Switches allow a manageable collision domain (area) to be set up for each LAN. When a message crosses from one LAN to another through a switch, it enters a new collision domain and in effect becomes a 'new' message in that domain. The explanation of how this works is beyond the scope of this article. With the collision detection problem solved, very large networks were able to be built.
Ethernet in the Internet
The Internet is made up of millions of PCs and other equipment connected together in thousands of dispersed LANs of varying sizes. The LANs pass data to each other through banks of switches and routers (very specialized switches) that are operated by communications companies and organizations around the globe.
If you work in an office, 10baseT Ethernet is probably the way all your local PCs, printers and other equipment is connected together. The 8-
|
·
|
100baseT or Fast Ethernet (100 million bits per second) is widely deployed in LAN backbones. Backbones are high speed data paths that are fed by many slower speed data streams, like 10baseT.
It is much like smaller roads feeding a few, slow moving cars onto a major highway (backbone), that carries more cars at higher speed. |
|
·
|
Eventually as more and more data comes together, 1000baseX or GB Ethernet (1 billion bits per second) is used to carry a tremendous amount of extremely fast moving data. In the traffic analogy, it is like an interstate highway.
This data keeps getting merged together into higher speed streams, called Optical Carriers, which use fiber optic cable to carry data. OC- |
Filenames and Filetypes
Filenames and filetypes are naming conventions used to identify files on computers.
The filename is used to identify the file for you, so that when you come back and look for it, perhaps far in the future you will remember what it means to you and that you can find it.
The filetype is used to identify and group files of similar type. As an example, all text files are identified by the filetype 'txt.'
If you've worked on a PC with DOS, which was the predominant PC Operating System (OS) before Windows, then you've used the 8.3 naming system.
The 8.3 file naming system used in DOS
The '8' refers to the maximum number of characters in the filename. Having only eight characters, often requires a lot of creativity in coming up with filename that accurately describes the file.
The '3' refers to the maximum number of characters in the filetype.
For example the file autoexec.bat has a filename of 'autoexec' and filetype of 'bat.'
Windows 95 extended the maximum length of Filenames
The maximum filename length was increased to 255 characters. All characters are allowed except for (\ / : * ? " < > | ).
This allows you to be very specific in naming your file. If you create a lot of files this flexibility in naming becomes very important.
Most filetypes are still just three characters. However, Windows can operate on longer filetypes.
Programs associated with filetypes
An additional feature in Windows associates each filetype with a specific application or program.
For example the 'xls' filetype is associated with the Excel application. If you double click a file with a .xls filetype, Windows opens the Excel program with the selected file loaded and ready for you to work with.
Sometimes you may want to open a file with a program other than the one Windows has assigned it to. This can be done, but we'll save this discussion for another tip.
The word Modem is an acronym for Modulate-
Getting pages from this web site to your PC requires a modem of some type (dial-
Most people still use dial-
PCs, printers and other digital output devices can not connect directly to telephone lines.
Digital devices produce outputs that can be in one of two distinct states, 0 or 1. Like a stair step, they jump from one level to the other, never stopping in between.
In contrast, analog signals like that which is produced by a human voice, vary continuously in time in a smoother, more hill shaped manner.
Digital signaling produces very high frequencies, that get attenuated (reduced) as the signal goes down the line. Loss of these frequencies at the receiving end can result in a loss of information.
The way around this is to use the digital 1s and 0s to vary an analog carrier, which is sent down the line.
Modulate
Modulate means to encode. A simple modulation type is Frequency Shift Keying. In this modulation scheme when the modem sees a digital 1 it sets the carrier to one tone (A) and sends it down the phone line. When it sees a 0 it changes the carrier to a different tone (B) and sends it down the line.
Demodulate
Demodulate means to decode. The receiving modem upon detecting a tone A converts it to a 1. And when it detects tone B, it converts it to a 0.
Training Tones
Data is not sent until after the modems have connected and trained. When your computer first connects to a line, the sporadic tones you hear are your modem and the one at the other end going through a training mode. They are searching for a rate they can both support using the current phone line. If your modem is 56K and the other is 14.4k, the fastest they can go is 14.4K. If during training the line won't support 14.4k, due to noise which causes errors, they have to drop to a lower rate that the line can support, like 9.6K for instance.
Morse Code
Morse code is a very old code where each character (letter, number or control) is assigned a unique sequence of dots and dashes. A Morse code operator sending dots and dashes down a telegraph line is modulating a carrier tone. A dot is a short burst of an analog tone. A dash is long burst of the same analog tone. Morse code was first used in telegraph communications. Many ham radio operators still use it today.
The Morse code operator receiving the stream knows what the relative length of the tones mean. He knows that a short tone represents a dot and a long tone is a dash. So he demodulates (decodes) the tones he hears on the line back into dots and dashes. Between each coded character sequence of dots and dashes is a short rest period which is required so that the the beginning and end of each charater is known.
In Morse code the sequence 'dot dot dot' represents the letter 'S' and 'dash dash dash' represents the letter 'O.'
So the sequence:
'dot dot dot -
coming down the line represents the letters SOS which happens to be the universal distress signal. People who have become trapped will often tap out SOS, hoping that rescuers will hear their call for help.
In Morse code, dots and dashes are sent down the line at a very slow rate, about 50 characters a minute. 10baseT Ethernet by contrast sends about 1,000,000 characters per second!
In modern digital communications the digital stream of 1s and 0s are modulated onto phone lines by modems using amplitude, frequency and phase modulation or various combinations of them. The receiving modem uses a compatible demodulation scheme to convert the modulated signal back into the original sequence of 1s and 0s.