WHICH IS SAFER,INTERNET EXPLORER OR FIREFOX

WHICH SAFER,INTERNET EXPLOREE OR FIRFOX ?

There is a lot of discussion going on about the relative safety of Internet Explorer vs. Firefox. In this article I say why I think most of the commentary is missing the point.


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The battle over the question in the title has been raging in discussions all over the Internet. Unfortunately, this is the wrong question. In fact, it is a meaningless question unless a lot of additional factors are considered. Security is a multidimensional problem and cannot be usefully discussed in the kind of simplistic comparisons that are being made.

I am not a professional security expert but there are some pretty obvious points that can be raised about how you define what is meant by “security”. The most popular way seems to be a kind of numerology where somebody with a vested interest like Symantec purports to count “vulnerabilities” or even “possible” vulnerabilities. The conditions where these vulnerabilities apply are usually not specified. Many questions have to be asked before any meaningful assessment of the severity of a problem can be made, For example, does having a firewall prevent them? Do typical anti-malware packages detect them? Does the user have to click on a link or do something stupid for the problem to apply? Can the problem be fixed by changing a default setting? How long does it take before a patch can be made? Not all “vulnerabilities” are created equal. A so-called vulnerability may be “potentially” very dangerous but not be a problem in practice because it easily fixed by standard measures or can only be incurred because of stupidity. So this numbers game looks very misleading to me.

The whole subject is quite complicated but in an attempt to keep this discussion reasonably short I suggest we replace the single question of the title with three questions (all pertain to Windows systems):

1. Which browser is safer for experienced computer users?

2. Which browser is safer for average computer users?

3. Which browser is safer for careless, uninformed or clueless computer users?

The answer to question 1 is that either browser will do. What browser is used by an experienced person is a matter of personal habits and preferences about different browser features. An experienced user knows what security precautions must be taken and will rarely get a problem just because of the browser that is being used. Personally, I use both Internet Explorer (IE) and Firefox. I prefer Firefox for most things but some sites only work in IE.

Next let’s consider question 2. The term “average” computer user covers a lot of different people so only a few generalities can be stated. The average PC user is not going to be familiar with the details of security measures but most will be aware that they need some kind of defense. If they have a PC bought in recent years they will have quite a bit of automatic protection such as anti-virus programs that update themselves and at least the Windows XP firewall. Also Windows update will be set to run unattended. Many PC users also have installed entire security suites. It is important to note the presence of these security measures because otherwise the question of which browser to use is moot.

For those people who have enough other security in place so that they can turn their attention to browser security, one question concerns updates. Both IE and Firefox have periodically been found to have security holes. IE has an apparent advantage in that it is automatically updated whereas at present Firefox has to be patched manually. Typical PC users can be lax about updating so that looks like a point for IE. However, this possible advantage is much lessened or even disappears because Microsoft can take many weeks to issue a patch for a known problem. Firefox patches come out within a few days after a problem is revealed. Which browser has the advantage here? For those who would keep up with the Firefox updates, I give the nod to Firefox on this particular issue. For procrastinators, maybe IE is better but future versions of Firefox are supposed to also update automatically. Note added later: Firefox version 1.5 is scheduled for release at the end of November, 2005. It contains an automatic update feature and that removes any advantage IE had for procrastinators.

There are also other security factors such as ActiveX, which I have discussed in detail on another page. On the issue of ActiveX, individual PC users will have to balance convenience with safety to decide on a browser. Knowledgeable users can configure IE to avoid ActiveX problems but I wonder how many average PC users will actually do what’s necessary. From a theoretical point of view, I think Firefox is safer because it doesn’t support ActiveX but from a practical view it can sometimes be inconvenient that some pages won't work for any browser but IE.

What about the average PC user who has an older system with Windows 98/Me? These people are totally ignored by most commentators but there are still quite a few of them around. They will be missing a lot of the security that Microsoft has added to IE in Windows XP SP2. Personally, I think that these systems are safer with Firefox. However, there is the psychological barrier that many people have about installing a whole new browser when they already have one in place. Also, IE has to be used for certain sites and this is another obstacle to using Firefox. For these users, I think that the theoretical answer to question 2 clearly is Firefox. In practice, however, most of these users will probably stick with IE. Hopefully, they will have enough security measures in effect to obviate the newer IE exploits that they are exposed to.

Now we come to question 3. This one is easy to answer. It doesn’t matter what this group uses for a browser. These are the ones that do not use firewalls or do not install security updates or blithely click on any old link. They have much bigger problems than what browser to use. Unfortunately, their problems are our problems, too. This group is where most of the worms and Trojans hide out. It is also where the crackers get their “zombie” machines to carry out Distributed Denial of Service attacks and conduct various criminal activities.

I have framed the discussion in terms of who the intended user is. To really discuss the issue of browser security would require a much more complicated metric. However, I think the discussion helps illustrate my contention that measuring security is not simple and that there is no easy answer that applies to everybody for the question of which browser is safer to use. If you held a gun to my head and demanded that I choose a browser for everybody, I would personally pick Firefox. But you still have to use IE for some sites like Windows Update whether you like it or not. And I haven’t even mentioned Opera or Netscape.

I am very interested to hear what you have to say about all this. Log on to http://tips.vlaurie.com and let me know what you think.

WHAT IS TROJAN HORSE

TROJAN AND HORSE

In addition to the viruses and worms discussed on the previous page, there is a third kind of malware known as a"Trojan horse" which we consider next.




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What is a Trojan horse?
The term Trojan horse is applied to malware that masquerades as a legitimate program but is in reality a malicious application. It may simply pretend to be a useful program or it may actually contain a useful function as cover for a destructive one. Screen savers are often used as a carrier. Trojan horses do not replicate themselves as do viruses and worms. However, a Trojan horse can be part of the payload of a worm and can be spread to many machines as part of a worm infestation. Many Trojan horses have been sent out as email attachments.

One favorite use of Trojan horses is to allow a malicious hacker ( more properly called a "cracker") to use systems of unsuspecting owners for attacking other machines or as zombies. Another use is for relaying spam or pornography. Yet another use is to steal account passwords and then relay them back to someone for fraudulent use. Trojans can also be destructive and wipe out files or create other damage. Recently, phishing scams have been making use of Trojans.

Sometimes social engineering is used to induce people to click on a link. Here's one that enticed people to try to download some photos:

Osama Bin Ladin was found hanged by two CNN journalists early Wednesday evening. As evidence they took several photos, some of which I have included here. As yet, this information has not hit the headlines due to Bush wanting confirmation of his identity but the journalists have released some early photos over the internet.

Instead of photos what they got was a Trojan.

Defenses
Many Trojans are recognized by the major anti-virus programs. However, not all Trojans have characteristics that trigger anti-virus programs so additional software is recommended. The spyware programs discussed on the next page should be considered as well as the references in the sidebar.

It is essential in the present conditions to have a firewall. The Internet is a two-way street. Unless your computer is properly protected, it is all too easy for unwanted visitors to gain access to your computer while you are on-line. Once into your system, a cracker can plant a Trojan or worm or do other harm. Good firewall software can make your computer invisible to all except the most determined cracker. Further, most firewalls will warn you if programs on your computer try to connect to the Internet without telling you. That will help to warn you if you get an infection. Note, however, that some Trojans may hide by piggybacking on essential services like your email client.

Unless they had a broadband Internet connection, I used to tell people that they probably did not need a firewall. However, hacking has reached the point where everyone, even those with dial-up connections, needs a firewall. My firewall keeps a log of the attempts that are made to probe my computer and once in a while I check it out of curiosity. The attempts are unceasing and come from all over the world. (I know because I look up some of the IPs.) Even my wife's dial-up AOL account is probed all the time. Many of these probes are not malicious but I see no reason to take chances on the good will of all these strangers.

The present version of Windows XP has half a firewall built in. Unfortunately, it monitors only incoming traffic and therefore is of no help in warning about programs on your computer that call up Internet sites without telling you. Also, note that that you have to specifically enable it. (Service Pack 2 turns it on by default.). I recommend a more robust program. If you want to, you can go for one of the commercial suites that include a firewall together with a variety of other programs. However, there are several very good free programs. The sidebar contains references.

Spyware and Adware
These types of pest are related to Trojans but are a little less destructive. They are discussed on the next page.

WHAT ARE SPYWARE AND ADWARE

SPYWARE AND ADWARE


The incidence of problem programs called "spyware" (or in their more benign forms "adware") has reached the point where Congress is even considering a law about it. Here's some facts about spyware and adware and ways to defend your computer.




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What are Spyware and Adware?
Spyware, adware and their variations are programs or applets that get installed on your computer by a download from the Internet. (You could also get them on a disk from somebody but that is less common.). There are basically three scenarios where problems arise:

1. You knowingly download and install something but do not understand all the functions of the program.

2. You download and install one thing but other things are installed along with it that you do not know about.

3. Something is downloaded and installed without your knowledge.

There are many software downloads available on the Internet that call themselves freeware. Quite a few of these are, in fact, free and come without strings. In the end, however, the cost of any software has to paid for by somebody, somehow. One way to support the cost of software is through advertising that is downloaded and displayed on the user’s computer along with the software. Many useful and reputable programs are now distributed this way. Often they come both in a version that is “free” (but with ads) and in a version that has no ads but has to be paid for. As long as the user is told up-front about the ads and about any tracking that might be going on, this form of adware has a perfectly legitimate role. For example, I use the adware version of the Opera browser. I do not use the browser very often and I wouldn’t pay for it but I am willing to have small ads running when I do use it. Actually, they are unobtrusive and I pay them no attention. [Note added later: Opera is now free.]

Note that I said that I was willing for ads to run while I was using the program. Less scrupulous software distributors may have pop-up windows showing ads whether you are using their program or not. Even worse offenders graduate to “spyware” and contain a component running all the time in the background to track your viewing habits on the Internet (and possibly other things). Your preferences are relayed to advertisers so that ads may be targeted specifically to what is perceived to be your interests. For example, if you visit a lot of sports sites on the Web, you may find ads for athletic equipment showing up on your computer.

Legitimate programs are straightforward in alerting you that advertising banners or pages will be downloaded to your computer and shown to you whenever you try to use that program. Others are less up front and bury the notice about ads and other actions in the EULA (End User License Agreement). Having seen this type of turgid legalese innumerable times when using Microsoft applications, most of us just click the “I agree” button without reading the stuff. If you do read the EULA thoroughly, you may find that you have signed away all your rights to privacy. How legally binding this really is, I am not competent to say, but personally I find the implications disconcerting. Still other software packages do not even bother with hiding details in the legalese but simply carry out surreptitious actions on your system without notifying you beforehand.

Drive-by Downloads or Foistware
Not content to entice you into using their spyware by providing some useful function, some firms download stuff to your computer whether you want it or not. Many Web sites have ad banners that contain download links. If you accidentally click on the ad, you may initiate a download. Some of these ads contain messages that your system "may" be infected with a virus or otherwise impaired in order to lure you into clicking on something. Depending on your browser security settings, you may then receive some unwanted software automatically or get the standard Windows pop-up message asking, "Do you accept this download?" If you click "Yes," spyware is installed. Note that the presence of a security certificate is no guarantee that something is not spyware. An example of a download window for a well-known problem program is shown in the figure below.


Sometimes, just viewing a page is sufficient. Many of these downloads take advantage of ActiveX controls in Internet Explorer (IE). The settings for Internet security zones in IE can be configured to prevent this. Also, Windows XP Service Pack 2 increases the security in this area of IE. Other browsers generally are not susceptible to ActiveX downloads. However, most browsers with insecure settings can be made to run Javascript or certain other types of code.

Lists of these types of spyware are available at the spyware database references given in the sidebar. Unless you are sure about a program, check it out on these lists before installing.

Other Problems
One issue is to how much of your privacy is invaded by the ad tracking. To some degree, it is the nature of an individual’s personal psychology that decides what is private. Some people are unconcerned while others react violently to the notion of being tracked. Privacy is a large subject and beyond the scope of this article but several references are given in the sidebar.

However you may feel about the privacy issues, the practical matter is that spyware uses your computer resources and bandwidth and often causes sluggish behavior or even crashes. Some spyware like the very popular file-sharing program Kazaa may even use your idle CPU time for whatever computational purposes they see fit. Many PC users have suffered significant degradation or worse for their system from the presence of spyware.

The most severe cases where the spyware is actually malicious and either causes deliberate damage to your system or uses your system for some nefarious purpose is usually considered a Trojan horse and is considered on the previous page.

Defenses
Because of the proliferation of spyware, many programs are now available for detecting spyware and cleaning it out. Anti-virus programs do not detect most spyware because the programs do not have the characteristics of a virus. Thus a separate application is needed that specifically targets spyware. Links to two free programs, "AdAware" and "SpyBot Search & Destroy" are given in the sidebar along with references for others. Unlike ant-virus programs, where installing more than one program is not recommended, it is a good idea to clean your system with consecutive application of two or more spyware removers. According to PC Magazine , the commercial programs Spy Sweeper and Spyware Doctor are the two best anti-spyware programs. PC World also chooses Spy Sweeper as its top ranked program.

Firewalls that monitor programs on your system that attempt to connect to the Internet will give you warning of the presence of spyware. The Windows XP firewall does not have this capability so one of the firewalls mentioned in the references in the sidebar is recommended. If another firewall is installed, turn off the Windows XP version. The update SP2 automatically enables the Windows XP firewall.

It's a good idea to check what programs run automatically at startup. Windows 98/Me systems can use MSConfig and Windows XP systems can use the services console to see what is running in the background. Unwanted programs can be detected and disabled. Any spyware can then be removed.

Avoiding spyware in the first place is the best defense. Use common sense in installing software. Check out any potential download with the spyware databases given in the references in the sidebar. Exercise caution when visiting strange Web sites.

Some references recommend disabling ActiveX entirely. While this will prevent many unwanted controls from installing, it will also break useful applications. A less drastic procedure is outlined on another page. Using the Firefox or other non-Microsoft browser is another recommendation for those who wish to avoid ActiveX problems. However, any commonly used browser is still susceptible to other types of script and the security settings for scripting should be consulted.

WHAT IS VIRUS & WORM

VIRUSES AND WORMS

It seems to be inherent in human nature that any activity involving large numbers of people will include some who behave in a harmful, anti-social way. Thus on the Internet there is a constant threat from malicious software or "malware." Two common types of malware are "viruses" and "worms."


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What a virus is
A virus is a self-replicating program that spreads by inserting copies of itself into programs or documents that already exist on a computer. The name comes from an analogy with biological viruses. These cannot reproduce by themselves but make use of the functions of infected cells to spread. Similarly, a computer virus makes use of the executable code in legitimate programs to carry out its purposes. A virus may be designed to be destructive to a system or to be a prank. In either case, the virus will rapidly reproduce itself until the system may be overwhelmed. Viruses spread to other systems when infected programs are copied to another machine. Documents with executable code like Word macros can also be vectors of infection. A very common method of spreading viruses is by attachments to email . Today a variant of a virus known as a worm is more often used.

What a worm is
Viruses and worms are often lumped together in the single category of virus but there is technical distinction. A worm differs from a virus in that it contains all the code it needs to carry out its purposes and does not depend on using other programs. Most recent instances of malware have been worms, spread primarily by email. Worms are designed to replicate rapidly and to use the Internet or other networks to spread with great facility. They may contain code to damage or erase files or may carry other malicious payloads. On a number of occasions, large numbers of computer systems have been brought down by worms. In addition to the damage from whatever payload they carry, the sheer number of worm copies can bring systems to a halt.

A very common method of spreading is by use of any email addresses on an infected computer. The worm searches address books, temporary Internet caches and other possible sources of email addresses. The worm then mails out random infected fake messages. It may use the addresses it finds not only as recipients but also may spoof mail to show them as senders. It may also combine random pieces of addresses into new fake addresses. All the messages will contain an attachment that is infected. None of this activity may be known by the owner of the infected machine and may go on for weeks or months. A single infected machine can send out thousands of worm-carrying messages.

Anti-virus programs
Most people know that anti-virus software is a necessity and most computers come with some form of anti-virus program already installed. (Note that anti-virus is a catchall term that refers to a variety of malware.) All the major programs check email as well as scanning your system. However, new viruses appear every day and anti-virus programs are only as good as their database or definitions of viruses. A program can't recognize a new virus unless it has been kept up to date. Anti-virus programs contain update features and these are automatic in the newer major programs. However, the big vendors like Symantec and McAfee no longer give unlimited free updates but start to charge after some initial period ranging from 3 months to 1 year. Very often people do not subscribe to the new updates and let their protection lapse. This leaves the computer open to any new virus that comes along. Actually, it may be better to periodically buy a whole new version of whatever anti-virus program you use. I have often found rebate offers that make the new program cheaper than the update subscription.

Personally, I find both the Norton and McAfee programs to be very heavy users of system resources. An alternative is one of the free programs like Grisoft AVG. In the past, Symantec's Norton has always seemed to get much better reviews for efficacy against infection than the freebies but a recent review by the magazine PC World indicates that there are several free programs that now provide acceptable levels of protection. Tech Support Alert gives a critique of the various free programs and describes an effective computer defense that uses free programs.

Firewalls
Worms have also been spread by intruders planting them directly on unprotected computers connected to the Internet. A firewall is essential to guard against such occurrences and is discussed in more detail on the next page.

Trojan horses
Another form of malware is the "Trojan horse" and we consider that on the next page.

How to Remove a virus

Virus

Usually every virus has two aspects – a finder and a replicator.

The finder searches for the new uninfected files and the replicator actually targets these files and infects it by multiplying itself.

How a Virus Affects a System

· It corrupts files

· It slows down the speed of the computer system

· It causes the system to hang frequently

It deletes various files

Sources of Virus Infection

A virus can enter the system and infect it through various sources. Some of the sources are

· Infected CDs, DVDs, pen drives, etc

· E-mail

· Browsing infected sites

Downloading files from the internet

How to Remove Viruses

Removing viruses, though technical, is yet a very simple process if all the required steps are properly followed.

The basic steps are:

· Buy or download an antivirus software

· Install the antivirus software

Update antivirus software with the latest virus definitions

· Do a complete system scan

A safe way to remove viruses is to use a bootable antivirus CD (containing the latest definitions) to scan the drive. Alternatively, you can attach the drive to a friend's computer that has an antivirus installed (with the latest updates) and perform a full disk scan.

However, if you cannot do any of the above options, you may want to try the following steps:

Steps to Remove a Virus from the System

Step 1
Install an Antivirus Program in the System

What is Antivirus program? An antivirus is a program that searches for, identifies and removes potential viruses existing in the computer system.

Antivirus software: Some of the commonly available antivirus programs in the market are -

· Symantec Norton antivirus

· AVG antivirus

· McAfee Scan

· Microsoft Antivirus

The antivirus software should be updated regularly to retain its effectiveness.

Before installing the antivirus, close all open applications and terminate any suspicious processes using Task Manager. Sometimes, you may need to boot into safe mode or safe mode with command prompt to delete suspicious programs and references to them in the Windows Registry (run regedit from the command prompt to open the registry editor).

Search engines are excellent tools to find out whether a certain process is harmful or not. You can also get steps on how to remove a specific virus manually.

Removing the virus beforehand might be necessary, as some viruses will not allow an antivirus to operate. However, if you are not successful, you may still continue with the installation.

Step 2
Scan the System to Identify and Locate the Virus

Usually, the antivirus will run automatically when the system reboots after the installation.

Therefore, it might identify the virus automatically.

Moreover, you may want to run a quick system scan to locate the virus.

Step 3
Troubleshooting the Virus Infected Areas

After the antivirus identifies the infected areas, the next step is to rectify those areas.

Methods of Eliminating Viruses

Generally, the antivirus adopts one of two methods to eliminate the virus:

· Removing the virus – When the virus can be easily identified and can be removed without affecting other files, then the antivirus removes it from the host place.

Quarantine – This is done when the virus cannot be easily identified removed from the file and the removal of virus means the removal of the complete file. In this method, although the virus is not eliminated, it is rendered inactive by moving the file into "quarantine" and renaming it.

Step 4
Perform a Full System Scan

Even after the virus is removed from the system, the next step is to scan the whole system to ensure that no infected files remain.

What if the Antivirus Fails?

It may happen that your antivirus fails to detect and get rid of the virus. In such a case, you can follow the steps given below:

· Take a backup of the entire data.

· Format the infected disk partition.

· In case the entire system is infected, the system will have to be reinstalled.

· Install the antivirus and the latest updates.

· Restore the backup.

Car Battery Charger

Car Battery Charger

This charger will quickly and easily charge most any lead acid battery. The charger delivers full current until the current drawn by the battery falls to 150 mA. At this time, a lower voltage is applied to finish off and keep from over charging. When the battery is fully charged, the circuit switches off and lights a LED, telling you that the cycle has finished.

Parts
Part Total Qty. Description
R1 1 500 Ohm 1/4 W Resistor
R2 1 3K 1/4 W Resistor
R3 1 1K 1/4 W Resistor
R4 1 15 Ohm 1/4 W Resistor
R5 1 230 Ohm 1/4 W Resistor
R6 1 15K 1/4 W Resistor
R7 1 0.2 Ohm 10 W Resistor
C1 1 0.1uF 25V Ceramic Capacitor
C2 1 1uF 25V Electrolytic Capacitor
C3 1 1000pF 25V Ceramic Capacitor
D1 1 1N457 Diode
Q1 1 2N2905 PNP Transistor
U1 1 LM350 Regulator
U2 1 LM301A Op Amp
S1 1 Normally Open Push Button Switch
MISC 1 Wire, Board, Heatsink For U1, Case, Binding Posts or Alligator Clips For

Notes

1. The circuit was meant to be powered by a power supply, which is why there is no transformer, rectifier, or filter capacitors on the schematic. There is no reason why you cannot add these.

2. A heatsink will be needed for U1.

3. To use the circuit, hook it up to a power supply/plug it in. Then, connect the battery to be charged to the output terminals. All you have to do now is push S1 (the "Start" switch), and wait for the circuit to finish.

Portable CD Player Adapter For Car

Whenever I'm in the car listening to my favourite CD, it always happens; my batteries go dead. To solve that problem, I built this extremely simple regulator circuit. It steps down the 12V from the lighter socket to 9V which is used by the CD player. Different CD players (I have a Sony Discman) may require different voltages, so just use the correct regulator. All the 78xx series regulators have the same pin out, so the circuit is universal.

Parts
Part Total Qty. Description
C1 1 1000uF 25V Electrolytic Capacitor
C2 1 10uF 25V Electrolytic Capacitor
C3 1 1uF 15V Elextrolytic Capacitor
C4 1 0.1uF 15V Electrolytic Capacitor
U1 1 7809 Or Other Regulator (See "Notes")

Notes

1. The voltage your CD player needs will determine which regulator you use. For 9V, use the 7809. For 6V, use the 7806. For the unlikely 5V use the 7805. Remember that whatever regulator you use, you will need to heat sink it. The metal case or metal cover on the case makes a great heat sink.

2. I built the circuit in a small case with the long wire to the cigaratte lighter plug coming out one end, then another, slightly shorter wire going out the other end to the CD player.

3. Triple check your wiring. You would hate to ruin an expensive CD player because you reversed one of the connections or hooked the regulator up backwards.

12 to 120 Inverter

12V to 120V Inverter

Have you ever wanted to run a TV, stereo or other appliance while on the road or camping? Well, this inverter should solve that problem. It takes 12 VDC and steps it up to 120 VAC. The wattage depends on which tansistors you use for Q1 and Q2, as well as how "big" a transformer you use for T1. The inverter can be constructed to supply anywhere from 1 to 1000 (1 KW) watts.
Important: If you have any questions or problems with the circuit, see the forum topic linked to in the Notes section. It will answer all your questions and provide links to many other (and better) inverter circuits.

Parts
Part Total Qty. Description
C1, C2 2 68 uf, 25 V Tantalum Capacitor
R1, R2 2 10 Ohm, 5 Watt Resistor
R3, R4 2 180 Ohm, 1 Watt Resistor
D1, D2 2 HEP 154 Silicon Diode
Q1, Q2 2 2N3055 NPN Transistor (see "Notes")
T1 1 24V, Center Tapped Transformer (see "Notes")
MISC 1 Wire, Case, Receptical (For Output)

Notes
Q1 and Q2, as well as T1, determine how much wattage the inverter can supply. With Q1,Q2=2N3055 and T1= 15 A, the inverter can supply about 300 watts. Larger transformers and more powerful transistors can be substituted for T1, Q1 and Q2 for more power.
The easiest and least expensive way to get a large T1 is to re-wind an old microwave transformer. These transformers are rated at about 1KW and are perfect. Go to a local TV repair shop and dig through the dumpster until you get the largest microwave you can find. The bigger the microwave the bigger transformer. Remove the transformer, being careful not to touch the large high voltage capacitor that might still be charged. If you want, you can test the transformer, but they are usually still good. Now, remove the old 2000 V secondary, being careful not to damage the primary. Leave the primary in tact. Now, wind on 12 turns of wire, twist a loop (center tap), and wind on 12 more turns. The guage of the wire will depend on how much current you plan to have the transformer supply. Enamel covered magnet wire works great for this. Now secure the windings with tape. Thats all there is to it. Remember to use high current transistors for Q1 and Q2. The 2N3055's in the parts list can only handle 15 amps each.
Remember, when operating at high wattages, this circuit draws huge amounts of current. Don't let your battery go dead :-).
Since this project produces 120 VAC, you must include a fuse and build the project in a case.
You must use tantalum capacitors for C1 and C2. Regular electrolytics will overheat and explode. And yes, 68uF is the correct value. There are no substitutions.
This circuit can be tricky to get going. Differences in transformers, transistors, parts substitutions or anything else not on this page may cause it to not function.
If you want to make 220/240 VAC instead of 120 VAC, you need a transformer with a 220/240 primary (used as the secondary in this circuit as the transformer is backwards) instead of the 120V unit specified here. The rest of the circuit stays the same. But it takes twice the current at 12V to produce 240V as it does 120V.
Check out this forum topic to answer many of the most commonly asked questions about this circuit: 12 - 120V Inverter Again. It covers the most common problems encountered and has some helpful suggestions.
Related Circuits

HIBERFIL.SYS and PAGEFILE.SYS

What are HIBERFIL.SYS and PAGEFILE.SYS?
These are system-generated files. They are used by Windows for hibernation and virtual memory control.
HIBERFIL.SYS is a file the system creates when the computer goes into hibernation mode. Windows uses the file when it is turned back on. If you don't need hibernation mode and want to delete the file you need to turn the hibernation option off before Windows will allow you to delete the file...
Start Control Panel Power Options
Go to the Hibernate Tab
Uncheck the Enable Hibernation box if you don't need the hibernation function
PAGEFILE.SYS is the virtual memory file. Typically, on install, Windows sets the size of the file at around 1.5 times your physical memory size however this size will vary depending on the amount of free space on the disk when the file is established and other factors. Most will find the default size works fine but it can be changed. Windows uses this file for its normal operation however if you really need the space you can delete it after turning the virtual memory option off but be aware that this can cause extreme instability in Windows to the point where it might stop so do this at your own risk...
Start Right Click on My Computer Select Properties from the menu
Select the Advanced Tab
Select Performance Settings
Select the Advanced Tab
Under virtual memory use the Change button to either set the size you want or turn it completely off. Note that if you turn it off or make the value too small you may notice a system slowdown or Windows may stop. Windows wants to use this file and if it's set to zero then in addition to a slowdown while running, on system shutdown you may think Windows has hung due to the extra time involved. You may have to experiment a bit if you set it lower than some minimum. The best advice would be to leave the file alone. The Elder Geek has a tutorial on the paging file that describes how to change its size in more detail.

MOODLE

Student Guide to using Moodle

1. What is Moodle?

Moodle is a learning management system which allows users to remotely retrieve learning materials and engage in online activities such as discussions, assessments, questionnaires and collaborative tasks. Moodle can be accessed via the following address http://moodle.solihull.ac.uk/ . No special login details are required, students are asked to use their existing network account details to get into the system.

2. Open and secure courses

Some courses within Moodle are locked, notice the key icon shown below. If a course has been locked it denotes that a special password is required to gain access. Details of how to obtain an enrolment key will be covered later in this guide. Conversely there some courses (Resources for all) which are open to all and required no enrolment key entry. First time users are requested to sign up immediately for the elibrary, learning objects and student resources.


3. Accessing Moodle for the first time within the College.

When you access the internet from within College this is the typical screen that you will be presented with. Select Moodle as shown.


First time users may be required to key in a username and password as illustrated below, simply use your existing network login details.

Once you have logged in, this is the view that you will be presented with.


As mentioned earlier, you are requested to sign up for the three courses shown below. Simply click onto to each link in turn.



For this example we will choose the elibrary. If this is the first time that you have accessed any Moodle course you will be asked to accept the Site Policy Agreement. This agreement spells out what will be expected of you when you start to use the site. Having read through it select, Yes. You will only ever have to do this once.

Having agreed to the site policy you will then be prompted to confirm that you are sure you wish to enrol yourself to this course. Select Yes.


This is the typical view of what you will see next. Details on navigating a Moodle course can be found later in this guide.


4. Accessing an enrolment key protected course.

Many courses in Moodle are enrolment key protected. This means that if a Moodle course has been specifically set up for you by your tutor, it will be listed on the Moodle home page and have a key icon along side it.


If this is the case, then once a course has been selected you will be asked to input an appropriate enrolment key – your tutor will provide you with this alphanumeric code. When requested type in your enrolment key then select 'Enrol me in this course'.


When prompted selected, Yes.



5. What does a typical course look like?


This section contains your grade book and edit profile area




This is a self-explanatory calendar section.
Green highlights show cross college events and pink markers show course events.



This section shows the courses that you currently signed up to.

This block provides news updates and important messaging.


This middle section is where you will find all your course materials and learning activities.


6. Finding your way around Moodle.

When you begin to open up files or move to different parts of the course, a file path or series of breadcrumbs start to emerge towards the top of the page. Simply click anywhere along this breadcrumb path to navigate back to your chosen location.

For example if you are in the elibrary and have opened a discussion forum, you can move back to the homepage by selecting elibrary as shown below.


If the course itself is divided into many different sections it can be tiresome constantly scrolling up and down the page. Moodle allows you to collapse the topic boxes and automatically create a 'jump to' pull down menu. The jump menu literally allows you to quickly display the topic box of your choice.

Jump to other topics here
Collapse topics here


Simply open the pull down menu and select the appropriate topic box.


7. Course appearance

When entering a course for the first time you may be presented with some icons that you have not seen before. The table below may help you identify them more easily.

A discussion forum
A questionnaire activity
A wiki (a file that two or more users can jointly edit )
Assignment release
A text file
An adobe acrobat file
A hot potato quiz
The contents of folder
A webpage
A word document

8. Languages

It is possible to change the language settings on your Moodle homepage as shown below.


Again using the drop menu select the language of your choice.



9. Editing your profile

Your profile describes who you are, what you can do and how you can change the way you perform some Moodle activities. By selecting Edit Profile on the left of your screen you will be presented with a small number of options that can be changed.

10. Frequently asked questions.

Q. Every time I try to open a file the pop-up blocker kicks in.
A. In order to overcome this locate the trusted sites section within your browser, ( for IE6 this is usually found in, Tools, internet options, security, trusted sites, sites, add then OK – it must be pointed out however that by adding any trusted site to your home PC you do so at your own risk ).

Q. I am unable to view certain Microsoft Office files that appear in Moodle.
A. If you are having difficulty in viewing certain Office files types then try downloading the relevant application viewer. These can be found at the following site.

http://www.microsoft.com/office/000/viewers.asp

Q. Who can see my grade book?
A. Only you and your tutor(s).

Q. If I leave my system for 30 minutes my course times out.
A. A time out setting has been activated to ensure that if your desktop is unattended for 30 minutes, users are prompted to log back in again. Whilst not a fool proof security safe guard, it does act as a further preventative measure against unwanted users misusing your Moodle account.

Q. Having problems printing documents located in your Moodle course.
A. Right click on the grey icon display bar at the top of the document, then select 'Standard'. The print icon will now be fully visible.

See the image below for further guidance.




Right click here, then select 'Stardard'.

EPSON P6000-P7000

Gadget: Epson P-6000 e P7000: i nuovi photo viewers
epson gadget p6000 photo viewer
Scritto da Maurizio Amatetti

Credits: Epson
I due nuovi album digitali firmati Epson, disponibili nelle versioni da 80 o 160 Gbyte, integrano un brillante display da 4” e il supporto per il formato Raw.
photogallery
Epson presenta P-6000 e P-7000, due album digitali dotati del display Epson Photo Fine Premia, un brillante lcd da 4” con risoluzione Vga (640 x 480 pixel) che visualizza 16,7 milioni di colori a 16 bit. Compatti e leggeri, i due viewer pesano appena 450 grammi e dispongono di una notevole capacità di archiviazione, pari a di 80 Gb per il modello P-6000 e 160 Gbyte per il P-7000).Un comodo jog dial consente di scorrere rapidamente le immagini e la funzione zoom permette di visualizzarne ogni dettaglio. I due device sono pensati per gestire grandi quantità di immagini e di videoclip provenienti da più fonti, e infatti sono compatibili con la maggior parte delle schede di memoria in circolazione (Sd, Sdhc, Commpact Flash, Multimedia Card, Micro Drive) e supportano il sempre più utilizzato file Raw.Alimentati da batterie agli ioni di litio, P-6000 e P-7000 sono disponibili rispettivamente al prezzo di 599 dollari e 799 dollari.

Lenovo PC

LENOVO LAUNCHES TWO NEW THINKCENTRE PCs
PLACES FOCUS ON POWER MANAGEMENT AND ON EMERGING MARKETS
Lenovo today announced two new PCs, the ThinkCentre M58/58p and the ThinkCentre A57e, aimed at helping customers stretch their IT dollar.
The ThinkCentre M58/M58p is Lenovo’s greenest, most secure and most manageable ThinkCentre desktop PC yet with Power Manager1, a ThinkVantage technology that allows PC users to control their electricity consumption remotely, and available for the first time ever on a ThinkCentre PC.
The ThinkCentre A57e, targeted at emerging markets, is perfectly suited for first time users that want a highly reliable, simple-to-use PC with accompanying services. Continuing Lenovo’s heritage of producing highly reliable PCs, it delivers rock solid quality and convenience by incorporating the latest ThinkVantage Technologies productivity and management tools.
“The design goal for the ThinkCentre M58/M58p was to be the greenest, most secure, most manageable and quietest ThinkCentre ever and we’ve achieved it in this eco-friendly powerhouse,” said Ronnie Lee, Country General Manager, Lenovo Singapore and Brunei. “And to meet the needs of this region’s emerging market and first-time-user needs, the ThinkCentre A57e gives businesses an affordable, hassle-free desktop solution.”
Greater Control, Greater Savings with Remote Power Management: ThinkCentre M58/M58p
The ThinkCentre’s M58/M58p’s Power Manager allows customers to save energy and lower electricity costs by enabling system administrators to monitor and remotely control the amount of electricity used by all Power Manager enabled desktops in a PC fleet. For example, PCs can be programmed to shut down evenings or weekends. Through the use of Power Manager and Intel vPro technologies, the ThinkCentre M58p provides the user with the lowest total cost of ownership of any ThinkCentre.
Further solidifying the ThinkCentre M58/M58p as one of the industry’s leading “green” computing solutions is the gold status achieved from the Electronic Product Environmental Assessment Tool organization, or EPEAT. Lenovo has a total of 24 ThinkCentre desktops that have become EPEAT Gold certified. EPEAT was created to provide a green standard for electronics purchases. The M58/M58p has also passed the stringent testing of GREENGUARD Environmental Institute, which probed for the presence of up to 2,000 potentially harmful contaminants, in addition to receiving the GREENGUARD Certification for Children & Schools, which takes into account children’s higher sensitivity to pollutants.
The ThinkCentre M58/M58p is also the first ThinkCentre PC to support Hardware Password Manager (HPM), which allows for oversight of user, supervisory, BIOS and HDD passwords. HPM is available in April, 2009 and requires a separate software purchase. Previous ThinkCentre versions of a password manager only allowed for password management at the software level. Additionally, the user can disable/enable USB and PS2 ports for complete “security” peace of mind.
Available in three form factors – Tower, Small Form Factor and Ultra Small Form Factor – the ThinkCentre M58p offers top performance with Intel vPro processing technology: Intel Core2 Duo E8x00 or Core2 Quad Q9xx0. The ThinkCentre M58 offers the Intel Q45 chipset with ICH10-DO. The ThinkCentre M5/M58p is also quieter and cooler than any previous ThinkCentre: across all form factors, it is up to six decibels quieter than the ThinkCentre M57/M57p and the hard drive and the processor power module run six and eleven percent cooler, respectively, than the M57/M57p. Embracing new technology, the M58/M58p is the first ThinkCentre with onboard Displayport.
The ThinkCentre M58/M58p comes with a limited, three-year onsite warranty with next business day service. End of life disposal solutions round out Lenovo’s commitment to green computing and preserving the environment. By doing so, customers may be able to receive cash back to offset the costs of future PC purchases, further lowering their total cost of ownership.
Built for Emerging Markets: ThinkCentre A57e
The ThinkCentre A57e continues Lenovo’s heritage of making highly reliable PCs and delivers rock-solid quality and convenience to customers by incorporating the latest ThinkVantange Technologies including Rescue and Recovery with Express Repair for recovering many system issues in 2-3 minutes and System Update that automatically downloads the latest updates over the Internet.
It provides emerging-market and first-time users access to the latest Lenovo technology and award-wining service and support at an attractive price point.
The ThinkCentre A57e incorporates the latest Intel technology with the Intel ATOM processor and is ideal for first time buyers looking at empowering their business with affordable, hassle free desktop solutions. Lenovo’s ThinkCentre A57e inherits the ThinkCentre’s ease-of-use design and is built to international quality standards with a stainless steel chassis for greater durability
Preloaded Windows Operating System and Microsoft Office (Trial)/Adobe Reader makes A57e ready for daily business use out of box.
The ThinkCentre A57e is designed to perform in severe environments making it ideal for first time PC users and customers in emerging markets. The hardworking Lenovo A57e delivers secure and reliable word processing capabilities while delivering social networking, photo and video entertainment functions that make it an ideal all round PC. The A57e comes with 1 year onsite support with options for a 3-year upgrade.
Pricing and Availability
The ThinkCentre M58/M58p desktops start at SGD 936.00. The ThinkCentre M58/M58p is available immediately in Tower and Small Form factor versions, while the Eco Ultra Small Form Factor will be available in December, 2008. All products will be available through Lenovo business partners. The ThinkCentre A57e will be available immediately starting at SGD 650.00. Monitors sold separately.

Epson Re-engineers its Micro Piezo Technology

Epson Re-engineers its Micro Piezo Technology By -->Printers/Copiers Just AnnouncedWed 26 Nov 2008 digg this slashdot this Manila, Philippines -- Epson, a world leader in digital imaging, recently launched the Epson Stylus Office, a range of printers engineered to specifically meet the needs of small and medium enterprises (SMEs).In view of the rising material costs and a possible economic slowdown, SMEs face even more pressure to minimize their operating costs. A regional survey done by Gartner in 2007 showed that companies spend up to 3% of business revenue on document printing. The ASEAN SME Development Survey found that 58% of SMEs cited rising operations costs as a key concern to the bottom line and barrier to growth. As such, managing cost of operations will be key to the sustainability of SMEs.In a report from the Department of Trade and Industry, the SME sector comprises 99.6% of all registered firms in Philippines while employing 69.9% of the labor force, and contributing 32% to the economy. Because of these statistics, the SME sector is now recognized as the backbone of the Philippine economy.Epson believes that SMEs should be equipped with a more efficient printing technology that will ensure better productivity, superior print quality, low cost of ownership, and more functions at an affordable price range. "On Epson's 10th year in the Philippines, we are proud to offer business solutions that can provide better productivity and quality. We believe that businesses especially the SMEs, considering the economic scenario, will be more discerning and will require superior industry-standard options that will ensure that their investments yield maximum benefits. This is the perfect timing for Epson to offer its global technologies that are specifically re-engineered for the needs of SMEs," says Epson Philippines Corporation Senior General Manager and Division Head for Sales & Marketing Eduardo Bonoan.Re-engineered Epson Micro Piezo print head technology for Laser-like Quality and Speed Epson's new Micro Piezo print head delivers perfectly spherical dots with high precision dot placement, delivering laser-quality image resolutions of up to 5,760 by 1,440 dots-per-inch (dpi).With this new print head that sports 360 nozzles per inch (as compared to 180 nozzles previously), SMEs are able to achieve an increased printing speed - at laser default quality - of up to 2 pages per second. Combined with Epson's Durabrite Ultra, resin-coated pigment inks, prints from the Epson Stylus Office dry instantly; in addition, they are both water and smudge resistant.Enhanced Functionality with Wireless ConnectivityWireless network printing feature is available in selected models of the Epson Stylus™ Office, enabling SMEs to print their documents without the need for messy wiring.Low Cost of OwnershipThrough the line, Epson Stylus printers are equipped with Epson's economical INKdividual cartridge system to give SMEs the cost-saving option of replacing only the color that has run out instead of changing the full ink sets. Another cost saving appeal of the Epson Stylus Office printers is its low power consumption of only 1 1 watts in active, printing mode. This is equivalent to the energy consumption of a small light bulb.The Epson Stylus Office will be available through authorized dealers from November 2008 and are priced at -• T30- PHP 4,995.00• T40W- PHP 6,995.00• TX300F- PHP 6,995.00• TX600FW - PHP 1 1 ,995.00Photo shows: Eduardo Bonoan, Senior GM, Division Head for Sales and Marketing; Hideto Nakamura, President, Epson Philippines Corporation; Michael Mondragon, Senior Manager, Head for Product Management; Jay Rafiola, Group Head for Retail Product Management during the Epson Stylus Office Product Launch