Scuba Diving Computers – Types and Styles

A scuba diving computer can be a divers best friend. It will allow you to stay down longer than if you were diving off of tables. There are many types and/or styles of dive computers you can choose from. Which one is best is really personal preference and is suited to the way you dive. The following are some of the choices you will have when purchasing your dive computer.

Console Dive Computer

A console dive computer is attached to the rest of the equipment via a hose. The console dive computers typically come with a pressure gauge. The readouts are typically larger than on a wrist dive computer so they can also be easier on the eyes.

There are also options for a scuba dive computer to be mounted on your hose (this is the type we currently use) or clip onto your BC. Choose whichever is more comfortable for you and fits into your price range.

Wrist Dive Computer

The wrist dive computer is very popular. These types of computers look like large watches and are worn on the wrist. They will tell you all you need to know at a glance. Some wrist dive computers are also able to be mounted in a console.

Sometimes the faces may be a bit small for all the information the computer can display, so make sure you will be able to read it underwater.

Unless they are air integrated and wireless (see below) wrist dive computers usually do not come with a pressure gauge. One small disadvantage here is that these can be pretty easy to misplace/lose.

Air Integrated Dive Computer

Air integrated dive computers are becoming more commonplace. An air integrated computer measures the tank pressure and then calculates how much more time you have left at the current rate of air consumption. The air integrated dive computer will tell you how much time you can spend at any exertion level.

An air integrated computer replaces the need for a submersible pressure gauge (SPG). One downside of an air integrated computer is that if it fails, you lose information on how much air you have left in your tank. Dive over.

Nitrox Dive Computer

With nitrox diving becoming more and more common, so are computers that are nitrox compatible. Even if you aren’t diving with nitrox now, if you are even thinking of diving with nitrox in the future, it is probably worth it to purchase a nitrox dive computer. This will save you the expense of buying a whole new computer in the future. However, if don’t think you will ever dive with nitrox, then there is no reason to pay for this feature. A standard air computer is probably $100+ less than its nitrox counterpart.

Hoseless Dive Computer

The hoseless dive computer consists of the receiver (typically worn on the wrist or mounted on the BC) and a transmitor. The transmitor attaches to the high pressure port of the regulator first stage and then sends your air information, wirelessly, to the receiver. The receiver looks the same as normal dive computers.

This setup cuts down on the number of hoses you need. There are now even hoseless dive computers that can accept signal from multiple transmitors – so you can even keep an eye on your buddies air consumption. Of course, this capability is really for the more advanced technical divers who may use different tanks on one dive. And, of course, we are talking some pretty high price tags here.

So just think about how you dive and what capabilities you need. The right dive computer for one person can be completely wrong for another person. Choose one that you are comfortable with and one that is right for you wallet.

Dianne Rein runs a scuba diving website at http://www.scuba-diving-smiles.com You can read her complete guide to scuba diving computers as well as scuba diving watches and other equipment on her website.

Article Source: http://EzineArticles.com/expert/Dianne_Rein/133703

 

Security, Malware, And Your Computer

Computers are practically in every aspect of our lives these days and our reliance on them is heavy. They are used as tools for work, data storage, schoolwork, shopping, and entertainment. Because so much information is typically stored on our computers we must always make sure they are protected from that loss of information. Businesses have to secure information on their computers to protect it from exploitation by hackers. And the home computer user is no exception to the requirement to protect computer information because there can be credit card numbers, social security numbers, and other sensitive personal information stored on their computer or transmitted when doing online shopping. There is a term used for this and it is “computer security risk.” This term refers to the likelihood that some action could cause the loss of information, computer hardware, or denial of service.

When computer security is put at risk intentionally, it becomes criminal in nature or we call this a computer crime. Another relative of the computer crime is the cybercrime. The FBI pays especially close attention to cybercrimes and there are other types of crimes related to them such as corporate spying, unethical computer activity, cyberterrorism, hacking, cracking, and cyberextortion.

Hacking at one time had a positive meaning to it but since computer crimes were introduced, it falls in the bucket with the rest of them. The hacker is the person who gains access to a computer network illegally. They sometimes use the excuse that they were only trying to break a network’s security so as to make the administrator aware of any security deficiencies.

Closely related to the hacker is the cracker. But the cracker never has been viewed in a positive light. The cracker always has had the intent to gain access to computer and its network to do harm to it or commit a crime like stealing information stored on it. The cracker, like the hacker, has to know what he or she is doing so advanced computer skills are needed in order to pull these crimes off.

Then there are the cyberterrorists and cyberextortionists. The cyberterrorist has a political motive behind his or her activities and it is to do harm to computers to adversely affect a political system. Cyberterrorism requires extensive planning, skilled people to carry it out, and money to fund it. It is much like the classic terrorist attack.

The cyberextortionist is the one who commits the crime of extortion via email. They will hold a company hostage by threatening to release sensitive company information or harm a company’s computers and network if not given some confidential information and/or money. Sometimes these criminals are aware of security leaks that will allow them to exploit the computer. It is much like classic extortion except carried out through computers.

Then there is the employee who wants to get revenge on his or her company because of some perceived wrong done to them or they want to pad their pockets. These people are known as the unethical employees and what makes them so dangerous is that they many times know how to get into the system.

Not everyone has the computer skills required to be a cracker or hacker so there is another classification known as the “script kiddie.” This person is usually is a teenager attempts to harm a computer system but cannot do much because he or she does not know much. This person will use canned programs and scripts to attempt to do the hacks and cracks.

Some unethical businesses try to gain an unfair advantage on their competition through an illegal activity known as corporate espionage. The same unethical businesses will hire a corporate spy who is highly-proficient in computers and technology to break into the target corporation’s computers. The corporate spy will then steal information or even sabotage the target computer.

It is imperative that home and business computer users take action to shield their computer from these threats to their security. Computer security methods are not 100% foolproof but they do decrease the risk to computers significantly. As soon as a solution is found to protect against one threat, someone figures out a new way to gain unauthorized access to them. Computer users on home networks are more at risk to have information stolen than are computers on business networks mostly because of the more advanced security on the latter. And the internet is a network even more susceptible and at risk when it comes to security. Another problem with security on the internet is that there is not one centralized point to manage security and safety on the information highway.

You are probably wondering now if your computer is secure from threats such as these. There are ways you can get your system evaluated. You can find sites on the internet that offer services that will access your computer and report to you any security vulnerabilities found either through internet browsing or the e-mail. These same companies many times offer tips and suggestions of ways to protect against the vulnerabilities. Another resource in the fight against computer security threat is the Computer Emergency Response Team (CERT) Coordination Center which also offers suggestions.

Security attacks against computers usually involve things like worms, viruses, denial of service, Trojan horses, and spoofing. All of these, the computer virus is the most famous. A computer virus is basically software that is designed to do damage to the files on your computer once it gets installed on it. All if it is done without the user giving permission and without the user’s knowledge at first. A computer virus, once it gets in your computer, will spread and cause more damage. It will do things like delete files and corrupt your computer’s operating system and render it inoperable. Thus it was tagged with the term “virus” because it acts much the same way as human virus does: it gets in and spreads throughout the body and causes illness or damage in some cases. Protection against viruses is available through anti-virus software.

An offshoot of the computer virus is the computer worm. A computer worm is much like a virus with the exception that it will find some perfectly valid executable program on your computer and attach itself to that program. When the user runs the program, the computer worm will attack. Computer worms can consume a lot of network bandwidth while they replicate across a corporate network.

And now for the famous Trojan horse computer threat that derives its name from the famous story in Greek mythology. What a Trojan horse does is hide itself in a program that looks like a valid program but in reality it is not. Trojan horse programs do not replicate like the viruses and worms do.

All these different types of threat software are known as malware which is term used to refer to malicious-logic programs. Malware, as the name implies, does damage to your computer. There are other variations of worms, viruses, and Trojan horses but we are just discussing these three for this article. And you should know how to suspect you have been attacked by one or more these malicious programs. You should be suspicious that you have been attacked if your computer shows one or more of these signs:

Programs you use suddenly don’t work like they used to:

  • Files are missing or corrupted
  • Strange music or sounds are heard on your computer
  • You start running out of memory for no apparent reason
  • Strange files show up on your system
  • System properties begin to change
  • Popup windows with odd messages and/or images display

The ways in which these malicious programs do their damage or drop their “bombs” can be one any one of the following:

  • A user runs a program infected with the virus. This is why virus scanning software that checks a program before running it is so important.
  • A user boots a computer and the virus is installed on the boot sector. It is recommended that you remove all media files when you shut down your computer.
  • A user connects to a computer that is not protected against viruses on the network (such as accessing a shared drive). So the user opens a virus-infected file on a shared drive and now the user’s client computer has the virus.
  • A user opens up an email attachment that contains an executable file with a virus. This is why it is so important to not open up executable email attachments unless you know the sender and the attachment has been scanned by anti-virus software.

And another big problem with malicious logic programs is that new ways to implement them are discovered every day. Security websites try to stay on top of each new malware implementation so that users can be alert for them. Take basic safety measures to protect your computer such as installing a good anti-virus package that gets updated with new malware detection logic automatically. Never open up suspicious email attachments. Be careful of the internet sites you visit (i.e., don’t visit Warez sites), and run anti-spyware programs. Take the media out of any alternate boot devices you have so that a virus cannot get stored on it and be introduced at boot time. Finally, stay informed from security websites as to the latest threats and what to look out for.

Guy Starbuck is a Super Geek and Health Phreak who writes for SpywareTool.com [http://www.spywaretool.com], NetworkSecurity.WS [http://www.networksecurity.ws], and ActiveDirectory.US [http://www.activedirectory.us].

Article Source: http://EzineArticles.com/expert/Guy_Starbuck/211129

 

A Short History of the Modern Computer

First programmable computer

The Z1 originally created by Germany’s Konrad Zuse in his parents living room in 1936 to 1938 is considered to be the first electrical binary programmable computer

The first digital computer

Short for Atanasoff-Berry Computer, the ABC started being developed by Professor John Vincent Atanasoff and graduate student Cliff Berry in 1937 and continued to be developed until 1942 at the Iowa State College (now Iowa State University). On October 19, 1973, US Federal Judge Earl R. Larson signed his decision that the ENIAC patent by Eckert and Mauchly was invalid and named Atanasoff the inventor of the electronic digital computer.

The ENIAC was invented by J. Presper Eckert and John Mauchly at the University of Pennsylvania and began construction in 1943 and was not completed until 1946. It occupied about 1,800 square feet and used about 18,000 vacuum tubes, weighing almost 50 tons. Although the Judge ruled that the ABC computer was the first digital computer many still consider the ENIAC to be the first digital computer.

Because of the Judge ruling and because the case was never appealed like most we consider the ABC to be the first digital computer. However, because the ABC was never fully functional we consider the first functional digital computer to be the ENIAC.

The first stored program computer

The early British computer known as the EDSAC is considered to be the first stored program electronic computer. The computer performed its first calculation on May 6, 1949 and was the computer that ran the first graphical computer game

The first personal computer

In 1975 Ed Roberts coined the term personal computer when he introduced the Altair 8800. Although the first personal computer is considered to be the Kenback-1, which was first introduced for $750 in 1971. The computer relied on a series of switches for inputting data and output data by turning on and off a series of lights.

The Micral is considered the be the first commercial non-assembly computer. The computer used the Intel 8008 processor and sold for $1,750 in 1973.

The first workstation

Although never sold the first workstation is considered to be the Xerox Alto, introduced in 1974. The computer was revolutionary for its time and included a fully functional computer, display, and mouse. The computer operated like many computers today utilizing windows, menus and icons as an interface to its operating system.

The first PC (IBM compatible) computer

In 1953 IBM shipped its first electric computer, the 701. Later IBM introduced its first personal computer called the “IBM PC” in 1981. The computer was code named and still sometimes referred to as the “Acorn” and had a 8088 processor, 16 KB of memory, which was expandable to 256 and utilizing MS-DOS.

The first PC clone

The first PC clone was developed by Compaq, the “Compaq Portable” was release in March 1983 and was 100% compatible with IBM computers and software that ran on IBM computers.

For more interesting information on computers and the problems you might have and the solutions to these problems, check it out at rcbenterpriz.com/computer [http://www.rcbenterpriz.com/computer]

Article Source: http://EzineArticles.com/expert/Robert_Buford/217355

 

Computer Security

Computer Security is a branch of technology known as information security as applied to computers. Information security means protecting information and information systems from unauthorized access, use, disclosure, disruption, modification, or destruction. The objective of computer security varies and can include protection of information from theft or corruption, or the preservation of availability, as defined in the security policy.

Technological and managerial procedures applied to computer systems to ensure the availability, integrity and confidentiality of information managed by the computer system

Computer security imposes requirements on computers that are different from most system requirements because they often take the form of constraints on what computers are not supposed to do.

Typical approaches to improving computer security can include the following:

o Physically limit access to computers to only those who will not compromise security.
o Hardware mechanisms that impose rules on computer programs, thus avoiding depending on computer programs for computer security.
o Operating system mechanisms that impose rules on programs to avoid trusting computer programs.
o Programming strategies to make computer programs dependable and resist subversion.

Computer Security has three Layers:

o Hacking
o Cracking
o Phreaking

Hacking:

Unauthorized use or attempts to circumvent or bypass the security mechanisms of an information system or network.

Computer hacking always involves some degree of infringement on the privacy of others or damage to computer-based property such as files, web pages or software. The impact of computer hacking varies from simply being simply invasive and annoying to illegal.

Cracking:

The act of breaking into a computer system.
Software Cracking is the modification of software to remove protection methods: copy prevention, trial/demo version, serial number, hardware key, CD check or software annoyances like nag screens and adware.

The most common software crack is the modification of an application’s binary to cause or prevent a specific key branch in the program’s execution.

Phreaking:

The art and science of cracking the phone network.

Security by design:

The technologies of computer security are based on logic. There is no universal standard notion of what secure behavior is. “Security” is a concept that is unique to each situation. Security is extraneous to the function of a computer application, rather than ancillary to it, thus security necessarily imposes restrictions on the application’s behavior.

There are several approaches to security in computing; sometimes a combination of approaches is valid:

1. Trust all the software to abide by a security policy but the software is not trustworthy (this is computer insecurity).

2. Trust all the software to abide by a security policy and the software is validated as trustworthy (by tedious branch and path analysis for example).

3. Trust no software but enforce a security policy with mechanisms that are not trustworthy (again this is computer insecurity).

4. Trust no software but enforce a security policy with trustworthy mechanisms.

12 tips for computer security:

1. Update / patch ALL your software every now and then!

2. Check / adjust ALL your settings so they are safe, since they ARENT by default!

3. Use firewall, like ZoneAlarm to control what goes in and out from your computer!

4. Use good passwords: at least 13marks long, containing both letters and numbers. Remember to change your password every few months atleast and dont ever use the same password in two places!

5. Get a good antivirus program: NOD32, F-Secure or Norton Antivirus and keep it updated!

6. Don’t open or execute files that you are not 100% sure are absolutely safe nomatter where or how you get them.

7. Wipe your historyfiles (like cookies, internet history and temporary files, etc.), logs and personal files, with specific wiping program (like Eraser) instead of just deleting them.

8. Use encryption to enhance your privacy! Use encrypted email (like Hushmail or Ziplip), www-surfing and encrypt sensitive files on your computer (PGP).

9. When you are finished using some internet-based service like email, sign out of it rather than just closing your browser! Also, when you leave your computer, make sure that none of such programs or connections are left open that someone could abuse. In WindowsNT/2k/XP, press Windowskey+L to lock the workstation.

10. Don’t use public computers for anything you need to type in your logins, they usually have Trojan horses that capture your passwords.

11. Make backups and store them in safe place! Easiest way to do a total-backup is to make an “Image” of your harddrive or partition and store it on safe location, but floppies will usually be just fine for storing documents, etc.

12. Install and Use a Hardware Firewal

Regards,
Kethy Wright
http://www.perceptionsystem.com

Kethy Wright is having a good Skill in Computer Hardware & Computer Security Systems. Know about for your Computer Security from his knowledge here.

Article Source: http://EzineArticles.com/expert/David_Tuffel/218530

 

Buying a Used Computer Online – What to Look For Step by Step Before You Make Your Purchase

There’s one reason and one reason only to buy a used computer online, lack of money which is a good reason. For the purpose of this article, the term computer shall include laptops. This article will tell you what to look for and what not to look for in a used computer, step by step.

I would only consider buying a used computer if you can’t afford to buy the computer you want new and can’t afford a new computer at a level below that computer provided its features still have what you want. IE, if you can’t afford to spend $750 for a new Core 2 Duo computer but can afford to spend $500 on a new Core Duo computer or $500 on a used Core 2 Duo, I would probably get the new Core Duo Computer unless the features on the used Core 2 Duo you found you couldn’t do without. The main advantage of buying a computer used is the warranty and the ability to extend it, free technical help from the computer company and the fact that you know there is no spyware, adware and viruses on it and in all likelihood no pre-existing problems on the computer waiting to be discovered.

Once you decide you can only afford to get the computer you want used then the first thing I would do is look to to see if it’s available online from a large company that sells refurbished computers with at least a 45-90 day warranty. Refurbished computers include computers whose boxes were opened and never used as well as returned computers with no problems and returned computers with problems. These companies usually buy refurbished computers in mass and test, repair and restore them as applicable to their original factory setting before they are resold, so you’re not likely to get a stiff. If you are, you will be covered by their warranty. You usually can extend your warranty for a few years beyond the original 45-90 days, as long as it’s before your original warranty expires.

The next step below that is buying your computer used online. Usually when you are buying a computer used online, there is no warranty. If you are not sure if a computer includes a certain feature on it, you need to contact the seller and have him confirm by email if it does or doesn’t have that feature before you purchase it. Sellers are notorious for being deliberately vague on used computers. For instance, a few years ago I purchased a computer which the seller confirmed to me by email that it included an operating system and when I got it, of course it didn’t but because I had this in writing he replaced it with one that had an operating system. If I didn’t get him to confirm this, chances are he would have stated that nowhere in his sales description did he say an operating system was included and therefore he won’t replace it. If you don’t have a basic general knowledge of computers and you have a friend that does, I would have the friend check out the description before you make your purchase. Whatever you do, if you see the words “Sold as Is”- do not buy as that is the sellers way of saying you are stuck with it, once you receive it.

I would not purchase any computer that is not at least described as being in very good condition as most sellers have a tendency to describe the condition one level better then what it is. I also would not buy any computer that mentions any kind of problem in its sales listing even its been fixed as you’re asking for trouble. You should make sure the memory, hard drive, operating system, size and CPU is listed and what you’re looking for. Assuming everything is in order, I would insist that the seller cleans the computer of all spyware, adware and viruses, if applicable before they send it out. I once got a used laptop that I had to spend 5 hours cleaning that junk off it. Once you get the computer, run any security programs on it and if you see that the seller hasn’t sent you a clean computer, either tell them to refund you for the the whole computer or tell him you’ll keep it but you want a rebate for sending you an unclean computer.

One last thing before you make your purchase is to see what software is already on the computer and if there’s something you don’t want, ask the seller to uninstall it and if there’s something you want kept on, tell the seller to leave it on. I would have the seller send you the computer UPS ground as its likelier to be damaged if sent by air, insured for the full purchase amount and requiring you to sign for it when delivered.

Once you get your computer I would as I said earlier, run any security programs you have to make sure there’s no junk on it. I then would test the computer for its basic functions and once you have an internet connection established, download Belarc Advisor online which is a free download that reads what’s exactly on your computer in detail to make sure everything you were told was on the computer is on the computer in terms of software, system, RAM, hardware, etc. I also would make sure you have an anti-virus program operational before you start surfing the web.

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Article Source: http://EzineArticles.com/expert/P_Hershon/118829