Basic definitions of a personal computer system.

If you are studying personal computers as the beginning of your career in technology, or perhaps you are just trying to understand how things work on your home computer to better deal with problems and upgrades, you can't get away with not knowing some very basic definitions of the components of a personal computer system.

Hardware is the physical machinery that make up a computer system such as a hard drive, monitor, mouse, keyboard, CD-ROM drive, network card, system board, power supply, case, and video card.

In personal computers, the main system board is sometimes called the motherboard, it is the central printed circuit board (PCB) in and holds many of the crucial components of the system, providing connectors for other peripherals.

The main component on the main system board is the central processing unit (CPU), the brain of a computer system. The CPU carries out the instructions of computer programs, performs the basic arithmetical, logical, and input/output operations of the system. 

System boards will have expansion slots, a CPU socket or slot, location for memory cache and RAM, and a keyboard connector. Other components may also be present.

A slot is a narrow notch, groove, or opening. A socket is a hollow piece or part into which something fits. Systemboards contain both sockets and slots, which are the points at which devices can be plugged in. A CPU slot is long and narrow while a CPU socket is square.

Primary storage is RAM (Random Access Memory), which holds programming code and data that is being processed by the CPU.

A hard drive is called secondary storage while memory is called primary storage because programs cannot be executed from secondary storage but must first be moved to primary storage. Basically, the CPU cannot "reach" the program still in secondary storage for execution.

ROM is read-only memory. ROM chips, located on circuit boards, are used to hold programming code that is permanently stored on the chip.

Flash ROM can be reprogrammed whereas regular ROM cannot be. In order to change the programming code of regular ROM, the chip must be replaced. Upgrades to Flash ROM can be downloaded from the Internet.

BIOS stands for basic input-output system. It is used to manage the startup of the computer and ongoing input and output operations of basic components, such as a floppy disk or hard drive.

Computer software is a collection of computer programs and related data that provide the instructions for telling a computer what to do. 

System software provides the basic functions for computer usage and helps run the computer hardware. An operating system is a type of software  that controls a computers output and input operations, such as saving files and managing memory. Common operating systems are typically Windows based, but personal computers can also use an Apple or Linux based operating system as well.

Application software is computer software designed to perform specific tasks. Common applications include word processing such as OpenOffice.org Writer, a spread sheet such as Microsoft Excel, and business accounting such as Quick Books by Intuit.
 

Home Wireless Networks in Simple Terms

What is Wi-Fi and How Does It Work?

Understanding all the buzz words of wireless local area network (WLAN) technology, and explaining Wi-Fi in simple terms

In computer networking everything starts with the physical layer, which for many years was a copper wire. The physical layer was expanded to include anything that represent the wire, such as fiber optic cable, infrared or radio spectrum technology.

Wireless network refers to any type of computer network that is not connected by cables of any kind. While cell phone technology is often discussed as a form of wireless networking, it is not the same as the wireless local area network (WLAN) technology discussed here.

What is Wi-Fi?

As is often the case in technology, the marketing definition is not exactly the same as the technical specification.

The term Wi-Fi has often been used as a technical term to describe wireless networking. Wi-Fi is actually a trademark of the Wi-Fi Alliance, a trade association that promotes Wireless LAN technology. Manufacturers may use the trademark to brand products if they are certified by The Wi-Fi Alliance to conform to certain standards.

The actual technical standards for wireless local area network (WLAN) computer communication are know as IEEE 802.11.  IEEE refers to the Institute of Electrical and Electronics Engineers a non-profit professional association formed in 1963 by the merger of the Institute of Radio Engineers and the American Institute of Electrical Engineers.

IEEE 802 refers to a family of IEEE standards dealing with networks carrying variable size packets, which makes it different from cell phone based networks.  802.11 is a subset of the family specific to WLAN technology. 

A common misconception is that Wi-Fi is an acronym of Wireless fidelity, it is not. The Wireless Ethernet Compatibility Alliance wanted a cooler name for the new technology as the IEEE 802.11b Alliance was not all that catchy. The marketing company Interbrand, known for creating brand names, was hired to create a brand name to market the new technology, and the name Wi-Fi was chosen. The term 'Wi-Fi' with the dash, is a trademark of the Wi-Fi Alliance.

How does Wi-Fi work?

A Wi-Fi enabled device such as a personal computer or video game console can connect to the Internet when within range of a device such as a wireless router connected to the Internet.  wireless local area network (WLAN) technology allows your device to connect to the router, which in turn connects you to the internet.

In order to connect to the internet, you need a unique IP (internet protocol) address. On your home network, when your router is connected to the internet, it has a public address, that is the one that faces the internet, and is unique in relationship of other routers on the internet.

Your router also has a local IP Address of something like 192.168.1.2 and this is a private IP address space. Addresses beginning with  192.168 cannot be transmitted onto the public Internet and are typically used for home local area networks (LANs).

If you have four home computers, your router creates a home network and the four home computers have a unique number in relationship to each other.  Your local computers connect to the router, either by a wire plugged into the router, or through a wireless signal.

Routers are used to create logical borders between networks, and in this allow a gateway, such as an access point to the internet to be shared. In geek speak terms subnetting can be very complex, but what is happening here is the process know as subnetting.

Wireless Security

Would you allow a total stranger into your house and have him use your personal computer?  If you have answered no to this question, you have pretty stated your case why you need to enable some type of wireless security. 

Wireless security is a topic to itself, and deserves a separate article. The bottomline is, you need to enable some type of wireless security on your router to keep strangers from accessing your personal network.
 

Sources:

Wi-Fi Alliance http://www.wi-fi.org/index.php

Wi-Fi Stands for...Nothing  http://wifinetnews.com/archives/2005/11/wi-fi_stands_fornothing_and_ever...

The marketing company Interbrand explains the term Wi-Fi 
http://www.interbrand.com/en/our-work/WIRELESS-ETHERNET-COMPATIBILITY-AL...

Understanding Home Wireless Network Security

Would you allow a total stranger into your house and have him use your personal computer? 

Your reply back to that may be, I have a lot of bandwidth to spare, what do I care if the guy in the apartment next to me steals a piece of my network connection. Stealing internet access is only one part of the picture in wireless security.  

The other part, as our question suggests, is giving someone access to your wireless router is like allowing them access to your house.  If you have a home network, you probably have Microsoft file sharing turned on to share files between your computers.  Do you want your files shared with total strangers?

There are thieves cruising apartment complexes not because they are looking to steal a little internet bandwidth, but because they are looking to steal your identity.  They want those files on your computer with you account numbers, and the user names and passwords to access those accounts.

You need to enable some type of wireless security on your router to keep strangers from accessing your personal network.

Secure your wireless network router

First and foremost, make sure you change the default password on your router.  Typically the router is set to default settings, with the user admin and the password is admin. Change the admin password!

The next step is to choose a type of wireless security mode.  You'll see a few choices on your router, here's a quick run down of the basics. 

Wired Equivalent Privacy (WEP) is a security protocol released in the late 1990s as a way to provide security in a wireless network comparable to that of a traditional wired network. 

The more recent and more secure protocols are Wi-Fi Protected Access (WPA) and Wi-Fi Protected Access II (WPA2). Both were developed by the Wi-Fi Alliance to secure wireless computer networks. The current recommendation of the Wi-Fi Alliance is the use of  WPA2 encryption.

If the Wi-Fi Alliance recommends WPA2 encryption, you might ask, why is there even a choice.  If you have multiple wireless devices, you have to drop back to the lowest common denominator. From best to worst is WPA2, WPA, and WEP.  Use WPA2 if your device allows it.  If you have one device that can only work with WEP, then all the devices must be set to WEP.  The newer equipment can drop back to the old encryption schemes, but the older equipment can not use the newer schemes.

You may see other choices other than the three mentioned here, but they are for more advanced business use. The focus of this article is for home use, or small business use. 

The last step in securing your wireless router is choosing a secure shared key.  This is the password, sometimes called a pass phase, will be entered on the router, and entered again on each device as it is configured.  Use a strong password, that is something that is at least 8 digits long that is a combination of letters and numbers.  The less easy the password can be guessed, the more secure you are.  If your network name is MyBusiness make your pass phase something much more complex than MyBusiness1.
 
Other Settings on Your Wireless Network Router

One additional method of security that is often mentioned is disabling the broadcast of SSID.  This means that the name of your network will not be visible to wireless devices.

While you can make the argument that selecting disable on the Wireless SSID Broadcast is an additional layer of security.  If you have secured your wireless router as we have discussed in the previous section, someone being able to see the network will not be able to easily access it, and in many cases disabling the broadcast of SSID is more of a pain than a security enhancement.

You may also see some settings for the Wireless MAC Filter on your router, and it is also sometimes mentioned as another layer of security.  For the typical home or small business network this feature is another case of minimal extra protection, with the possibility of creating problems, rather than resolving them.

The most basic, and easiest, way to secure your router is to use the strongest encryption method possible, and use the most complex password you can.  As with the analogy of the thieves cruising your apartment complex looking for a network with an open door, they will most likely pass on the locked door if they can find one close by that is unlocked.

Understanding the True Cost of an Inkjet Printer

Is it Cheaper to Buy a New Printer Than it is to Just Replace the Ink?

Throughout the internet you will find many articles asking the question, is it cheaper to buy a new printer than it is to just replace the ink cartridges. We will explore the various aspects and angles of this question.

Proving the Premise

For the sake of proving the premise of the question, we shopped the HP.com website, and selected an inexpensive printer, the HP Deskjet 1000 Printer which sells for $29.99. 

According to the product specifications the printer comes with one HP 61 black cartridge with a yield of approximately 190 pages and one HP 61 tri-color cartridge with a yield of  approximately 165 pages.

On the very same HP.com website we can order a new HP 61 Black Ink Cartridge which according to the specifications the cartridge yield is approx. 190 pages, for a price of  $13.99. Also the HP 61 Tricolor Ink Cartridge with a yield of approx. 165 pages, costs $19.99.  The cost to replace both ink cartridges is $33.98.

So at least on the surface, we have proven the basic premise that is it cheaper to buy a new printer than it is to just replace the ink cartridges. But now let us explore some other issues.

The Myth of the Unfilled Ink Cartridge

Many articles on the internet claim that the new printer comes with starter ink cartridges that are nearly empty, that they are not as filled as the ones you buy to replace them.  In the case of our shopping example this is not the case.

The Myth of Inkjet Refills

There are many places selling refilled cartridges with the claims of saving money over buying the manufacturers brands. There are also various kits sold for refilling ink cartridges. I have worked in various capacities as a technician representing both companies that sold printers and copiers, as well as supported them as an employee working for the company using the printers. Refilling ink cartridges or using cartridges from companies that refill them is a very mixed bag. 

I have not seen consistent results from refilled cartridges. Because of numerous problems, I urge companies not to use refilled cartridges, or try filling them on their own. If you are looking to save money on ink cartridges, there are other things to consider, and that I would recommend, instead of using refilled cartridges.

Always print in Black

If you do the math on the ink cartridges in our example you will see that that the cost per copy on the color cartridge is about 12 cents per copy, while the black costs around 7 cents per copy. The cartridge yields are based on printing a standard test page.  A densely colored document will use ink even faster. How many times do you print a  multicolor page just for the sake of some text data that does not need to be in color?

Consider printing text documents only in black, and save color only for photos.  If you look at the printing preferences on the printer set up of your printer in the operating system, you will find the option "Grayscale Printing" which will disable the color printing and have your output from the printer only use the black cartridge. While you are looking at your print settings you might also want to look to see if your printer offers a less than standard print quality.  Sometimes you will see a fast or economy mode,  while decreasing the quality of the output, it also uses less ink.

Of course the easiest way to cut down on printing costs is to carefully choose what you print. Do you print e-mails with just a few lines of text just so you can read them later?

Consider a Laser Printer Instead of an InkJet.

The price of a black Laser Printer costs several times that of an inkjet, and the price of a toner cartridge will cost a lot more than an inkjet printer. Don't let the initial sticker shock scare you.  If you calculate the actual cost per copy of laser printer, you are looking at something closer to the 2 to 4 cents per copy price range, which is significantly cheaper than the inkjet.  Calculate the cost per copy savings over time, and figure out how long it will take to recover the initial upfront costs. It may not take all that long at all.

There are other advantages of a Laser Printer over an Ink Jet.  Laser Printer documents hold up better than ink jet documents. Some Ink Jet documents smear if exposed to water or moisture, and fade over time. Ink cartridges may dry up, while toner cartridges have a longer life span if not in use.

In a business environment I strongly urge folks to focus on cost per copy, rather than cost per printer.  The price of laserjets have dropped dramatically in recent years. If you have multiple workstations each having their own inkjet printer attached to them, it does not take long at all to justify the cost of a shared laser printer. If you are printing more than a few hundred pages a month, you should be looking at a laser printer.

Why not just replace the printer, instead of buying ink cartridges?

The analogy most often used to explain why the low end printers seem to cost so little is that of giving away the razor to sell the razor blades. In that sense, it does seem that every year there is a new razor being made that uses a new type of razor blade that is different than any other.

In the simplest scenario replacing the printer instead of buying ink cartridges may seem to make sense, but only at the very low end of the spectrum. A copier, fax, printer combination unit will cost a lot more than the simple printer, but still use the same ink cartridges.  In this case it does not make sense to replace it when the ink runs out, so the other tips here come into play.

A very minor consideration, but potential issue, is that with every new printer you buy, that requires new drivers and software to be installed on your computer. Anytime you install a new printer you have the possibility of formatting issues with documents created for the old printer, using the old printer's drivers.

One more consideration, that comes up quite a bit in our world today is the waste in our world. How environmentally friendly is it to throw away a fully functional printer for the sake of saving a dollar on an ink cartridge?

Shop Wisely

With any device such as a printer or copier, that uses consumable supplies, like toner or ink, do some homework before buying.  The cost of the device itself is only a small part of the total picture. Even on more expensive devices, what appears to be a bargain, because the cost of the device appears cheaper, may not be a great deal because of the price of supplies. Check out the price of the device, as well as the price and yield of supplies. Estimate your usage over time and calculate true costs,

Models of devices change often. The product chosen in this example was simply to illustrate the point and no endorsement is intended. The author has no connection to HP in anyway, prices and and information was taken from the hp.com website at the time the article was written. 
 

Workstation Tips and Tools

Clonezilla live is an open source application suitable for single machine backup and restore. (Similar to Symantec "GHOST")

Check it out at http://www.clonezilla.org/clonezilla-live/

SystemRescueCd is a Linux system rescue disk available as a bootable CD-ROM or USB stick for administrating or repairing your system and data after a crash. It aims to provide an easy way to carry out admin tasks on your computer, such as creating and editing the partitions of the hard disk.

Check it out at http://www.sysresccd.org/Main_Page