Programming : here you can learn and get a great informations for free

Introduction

Programming is the process of writing instructions for computers to produce software for users. It's the combining of minute details to form a cohesive whole. More than anything, it is a creative and problem-solving activity. The problem solving aspect of programming will become self-evident as we move forward. For now, I'd like to talk about the creative side.

At a high level, it's obvious that creating software requires creativity. You are building something for people to use. It must therefore be clever without being complex. It must be intuitive and elegant. What isn't obvious to most people is that creativity plays an equally important role at the micro level of building software. Every instruction that you type requires consideration. In this respect, I've always likened programming to writing a book or painting a picture. Ultimately you have a finished product, but it's the sentences and the strokes, and how they are combined, which is where the book, painting or program truly comes to life.

I sincerely believe that programming is a beautiful thing. However, I warn you that learning to program isn't trivial. You should be able to learn the basics with relative ease. Unfortunately, going from these basics to being able to write a useful program isn't easy. In fact, it can be quite frustrating. I tell you this so that you know what to expect, not to discourage you. How far you take this journey is up to you, this is but a start.......

PLEASE it's a free site and we can learn programing step by step 

Enjoy 

http://codingintro.com 

Here you find a useful site to study programming with small steps

http://teachingkidsprogramming.org

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Types of Information Security Controls

Security is generally defined as the freedom from danger or as the condition of safety. Computer security, specifically, is the protection of data in a system against unauthorized disclosure, modification, or destruction and protection of the computer system itself against unauthorized use, modification, or denial of service. Because certain computer security controls inhibit productivity, security is typically a compromise toward which security practitioners, system users, and system operations and administrative personnel work to achieve a satisfactory balance between security and productivity.

Controls for providing information security can be physical, technical, or administrative. These three categories of controls can be further classified as either preventive or detective. Preventive controls attempt to avoid the occurrence of unwanted events, whereas detective controls attempt to identify unwanted events after they have occurred. Preventive controls inhibit the free use of computing resources and therefore can be applied only to the degree that the users are willing to accept. Effective security awareness programs can help increase users’ level of tolerance for preventive controls by helping them understand how such controls enable them to trust their computing systems. Common detective controls include audit trails, intrusion detection methods, and checksums.

Three other types of controls supplement preventive and detective controls. They are usually described as deterrent, corrective, and recovery. Deterrent controls are intended to discourage individuals from intentionally violating information security policies or procedures. These usually take the form of constraints that make it difficult or undesirable to perform unauthorized activities or threats of consequences that influence a potential intruder to not violate security (e.g., threats ranging from embarrassment to severe punishment).

Corrective controls either remedy the circumstances that allowed the unauthorized activity or return conditions to what they were before the violation. Execution of corrective controls could result in changes to existing physical, technical, and administrative controls. Recovery controls restore lost computing resources or capabilities and help the organization recover monetary losses caused by a security violation.

Deterrent, corrective, and recovery controls are considered to be special cases within the major categories of physical, technical, and administrative controls; they do not clearly belong in either preventive or detective categories. For example, it could be argued that deterrence is a form of prevention because it can cause an intruder to turn away; however, deterrence also involves detecting violations, which may be what the intruder fears most. Corrective controls, on the other hand, are not preventive or detective, but they are clearly linked with technical controls when antiviral software eradicates a virus or with administrative controls when backup procedures enable restoring a damaged data base. Finally, recovery controls are neither preventive nor detective but are included in administrative controls as disaster recovery or contingency plans.

Because of these overlaps with physical, technical, and administrative controls, the deterrent, corrective, and recovery controls are not discussed further in this chapter. Instead, the preventive and detective controls within the three major categories are examined.

PHYSICAL CONTROLS

Physical security is the use of locks, security guards, badges, alarms, and similar measures to control access to computers, related equipment (including utilities), and the processing facility itself. In addition, measures are required for protecting computers, related equipment, and their contents from espionage, theft, and destruction or damage by accident, fire, or natural disaster (e.g., floods and earthquakes).

Harold F. Tipton

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what is the cache

 The cache

In the previous chapter, I described two aspects of the ongoing development of new CPU’s – increased clock frequencies and the increasing number of transistors being used. Now it is time to look at a very different yet related technology – the processor’s connection to the RAM, and the use of the L1 and L2 caches.

Speed conflict

The CPU works internally at very high clock frequencies (like 3200 MHz), and no RAM can keep up with these.

The most common RAM speeds are between 266 and 533 MHz. And these are just a fraction of the CPU’s working speed. So there is a great chasm between the machine (the CPU) which slaves away at perhaps 3200 MHz, and the “conveyor belt”, which might only work at 333 MHz, and which has to ship the data to and from the RAM. These two subsystems are simply poorly matched to each other.

If nothing could be done about this problem, there would be no reason to develop faster CPU’s. If the CPU had to wait for a bus, which worked at one sixth of its speed, the CPU would be idle five sixths of the time. And that would be pure waste.

The solution is to insert small, intermediate stores of high-speed RAM. These buffers (cache RAM) provide a much more efficient transition between the fast CPU and the slow RAM. Cache RAM operates at higher clock frequencies than normal RAM. Data can therefore be read more quickly from the cache.

Data is constantly being moved

The cache delivers its data to the CPU registers. These are tiny storage units which are placed right inside the processor core, and they are the absolute fastest RAM there is. The size and number of the registers is designed very specifically for each type of CPU.

Fig.  68. Cache RAM is much faster than normal RAM.

The CPU can move data in different sized packets, such as bytes (8 bits), words (16 bits), dwords (32 bits) or blocks(larger groups of bits), and this often involves the registers. The different data packets are constantly moving back and forth:

from the CPU registers to the Level 1 cache.

from the L1 cache to the registers.

from one register to another

from L1 cache to L2 cache, and so on…

The cache stores are a central bridge between the RAM and the registers which exchange data with the processor’s execution units.

The optimal situation is if the CPU is able to constantly work and fully utilize all clock ticks. This would mean that the registers would have to always be able to fetch the data which the execution units require. But this it not the reality, as the CPU typically only utilizes 35% of its clock ticks. However, without a cache, this utilization would be even lower.

Bottlenecks

CPU caches are a remedy against a very specific set of “bottleneck” problems. There are lots of “bottlenecks” in the PC – transitions between fast and slower systems, where the fast device has to wait before it can deliver or receive its data. These bottle necks can have a very detrimental effect on the PC’s total performance, so they must be minimised.

Fig.  69. A cache increases the CPU’s capacity to fetch the right data from RAM.

The absolute worst bottleneck exists between the CPU and RAM. It is here that we have the heaviest data traffic, and it is in this area that PC manufacturers are expending a lot of energy on new development. Every new generation of CPU brings improvements relating to the front side bus.

The CPU’s cache is “intelligent”, so that it can reduce the data traffic on the front side bus. The cache controller constantly monitors the CPU’s work, and always tries to read in precisely the data the CPU needs. When it is successful, this is called a cache hit. When the cache does not contain the desired data, this is called a cache miss.

Two levels of cache

The idea behind cache is that it should function as a “near store” of fast RAM. A store which the CPU can always be supplied from.

In practise there are always at least two close stores. They are called Level 1, Level 2, and (if applicable) Level 3cache. Some processors (like the Intel Itanium) have three levels of cache, but these are only used for very special server applications. In standard PC’s we find processors with L1 and L2 cache.

Fig.  70. The cache system tries to ensure that relevant data is constantly being fetched from RAM, so that the CPU (ideally) never has to wait for data.

L1 cache

Level 1 cache is built into the actual processor core. It is a piece of RAM, typically 8, 16, 20, 32, 64 or 128 Kbytes, which operates at the same clock frequency as the rest of the CPU. Thus you could say the L1 cache is part of the processor.

L1 cache is normally divided into two sections, one for data and one for instructions. For example, an Athlon processor may have a 32 KB data cache and a 32 KB instruction cache. If the cache is common for both data and instructions, it is called a unified cache.

source

Copyright Michael Karbo and ELI Aps., Denmark, Europe

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Security Threat

Malware comes in many different forms and some of the more common are viruses are those that infect systems when they are downloaded and opened by the user. Combating any malware can be a never ending battle. It seems as if there is always some new security threat you need to be aware of. One of the latest is CryptoLocker - a new form of ransomware.

Knowledge is power so finding out more about CryptoLocker is recommended, as well as how you can take steps to protect your systems.

What is CryptoLocker?

Ransomware is a virus that locks important files or systems and requests that users pay a ransom to unlock them. This is not a new form of malware, but there has been a recent resurgence and CryptoLocker is leading the way.

This particularly nasty piece of malware infects user systems and locks files, threatening to delete them unless the hacker is paid. It is being spread four different ways:

As an email sent to company addresses pretending to be from customer support from FedEx, UPS, DHL, etc. The virus is attached to the email, usually labeled as a tracking number.
In PDF documents that are attached to emails.

Via hacked websites that can exploit computer vulnerabilities to install the infection.

Through trojans that pretend to be programs you need to download in order to watch videos online.

CryptoLocker installs itself to the Documents and Settings folder on your system and then proceeds to search for specific file types like Microsoft Word Docs or Adobe PDFs. It applies an asymmetric encryption which requires both a public and private key to unlock. The public key is stored in the virus itself and is used to encrypt the files. The private key is hosted on the hacker’s server.

What happens if I get infected?

If your system is infected your files will be encrypted and a pop-up message displayed informing you that your personal files have been encrypted and that in order to get the key to unlock them (the private key) you need to pay up to USD$300, or a similar amount in another currency. This amount seems to change and has increased, with older versions asking for USD$100.

You will also see a timer counting down from 100 hours. If this reaches zero, your encrypted data will be deleted with a very slim chance of the files being recoverable. The preferred method of payment is in BitCoins - a digital currency. The pop-up window has instructions on how to submit the payment - usually through an online payment method like Green Dot - MoneyPak.

The good news is, once you submit the payment, you will receive a key you can enter to unlock your files. The hackers have said that they won’t re-infect systems, and network security companies have confirmed that so far, this has been the case.

While many up-to-date virus and security scanners will pick up CryptoLocker, most won’t be able to recover or decrypt files even if the malware itself is deleted. If you see the pop-up window, itâs probably too late.

How do I prevent CryptoLocker from infecting my systems?

This is a serious piece of malware that should not be taken lightly. If you are worried about your systems being infected, here are five things you can do to prevent that from happening:

Be proactive - It is a good idea to educate yourself and your staff about this piece of malware and even implement and reinforce a no installing your own software rule. Also, having a backup and disaster recovery plan in place and functioning will go a long way in limiting the damage this program can do.

Check your emails closely - Closely look at every email that comes into your inbox. Pay attention to who sent it, the body text and even the subject line. If you see a slight spelling mistake in the name or even in the address e.g.,customersupport@fedx.com, you should be careful or maybe just immediately delete the email.

Beware of attachments - Always look at your attachments. If you get an email with an attachment from any sender you don’t personally know don’t open it. If you get an attachment from people you do know, but it isn’t something they would normally send, don’t open it. For all other attachments, try confirming that the file
attached is in fact legitimate by asking the sender.

Backup your data - Be sure to always backup your data on a regular basis. If you backup files on a daily or even weekly basis and are infected, you can easily wipe your hard drives and start again without losing much in the way of data.

Know what to do if infected - If you are infected the first thing you should do is disconnect from the network to limit the chance of the virus spreading to other systems. If you have backed up your system and data, you can probably revert your system. If not, your best plan of attack would be to contact us to see if we can help, as we may be able to get around the encryption or even delete it.

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XP Protection 2014 Virus

XP Protection 2014 Virus is a crafty browser hijacker to hook internet users computers with any permission and then keeps popping up when visit any website. Computers may get the virus when go to an unsafe website accidentally and get a pop up for you to click and download something. Once installed in a target computer, the XP Protection 2014 malware will redirect your website and you search engines. The annoying browser hijacker is supposed to target many browsers, Internet Explorer, Mozilla Firefox, Google Chrome and so on. When your computer get infected by the virus, it will freak you out by mislead your homepage to XP Protection 2014 adware pops up every time.

Once found its location in your infected computer, this Virus will modify the settings of your default search engine secretly and reset the DSN setting without your consent. The browser hijacker will display plenty of commercial advertisements and other pop-ups when you surf the internet and open a websites each time. Your homepage will be disabled by the disturbance of this Virus So you are unable to go on line normally and smoothly. So you are unable to go on line normally and smoothly. What's more, it will kill the internet users for the slow performance of the system.this Virus will spoil your system gradually without your knowledge if without a complete removal.

this Virus will sneak in your computer from the installation of freeware, adware, malware, spam and junk emails. The cunning virus will hide itself in your system after installed with a success and can steal your personal information to cyber criminals and bring a mess up in your computer without your consciousness and agreement. Therefore, when your computer gets the infection of the XP Protection 2014 Virus, please get rid of it as soon as possible.

How Can This XP Protection 2014 Infect the Computer?

Once sneaking into a fragile computer with success, this Virus is going to modify the default settings of the infected browser and then take over it completely. The XP Protection 2014 malware will mislead Internet users’ websites to an unwanted and irrelevant website. Apart from giving a redirection and a bunch of pop-ups on the screen, the virus is designed to install plenty of other threats, such as some unwanted programs and other viruses, on the infected computer without any consciousness or permission. Internet users have no ability to handicap the process of the uninvited programs and then they will detect the infected system showing a slow performance and coming across a crash at last. Victims should get rid of XP Protection 2014 popup as soon as possible or the browser hijacker will cause more damage.

Is XP Protection 2014 Bad For Your Computer?

XP Protection 2014 Virus has been classified as annoying browser hijacker is sponsored by cyber criminals to intrude victims’ browser. Once installed on a vulnerable computer, this Virus popup will redirect victims’ homepage or search results without any confirmation when they launch the infected a browsers. Instead of moving into a web as it should do, the browser will be enforced to move into XP Protection 2014 AD and display numerous commercial ad pop-ups or some so-called free games on the screen. The Internet users are unable to ignore or close the additional pop-ups because the pop-ups will launch themselves automatically and then lead an online traffic, which will interrupt victims’ online sessions. So it is very bad.

In a word, the XP Protection 2014 Virus is a tricky browser hijacker which is created by cyber criminals to intrude victims’ computers and then do some damage with the system of the infected computers. The settings of the default browser will be tampered and then it will redirect your homepage to amazon.com whenever you use a search engine to visit a website. The plenty of unwanted pop-ups will be beyond of your tolerance of limits and put an obstruction for you to go online. What’s worse, the victims will get the headache of the leak out of their confidential information for cyber criminals, which is a nightmare for internet users. If your computer gets the bogus browser hijacker, the more adware or malware will be appended to your computer and bring more damnity on your computer. Consequently, please get a 

complete removal at no delay.

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How To Compare Web Hosting Providers

If you need to create a site then chances are you could need the services of a hosting business to ensure that your site can feel created are living over the internet. Indeed there are so many companies available it can feel really difficult to render a preference.

Web hosting has grown to become a very big and worthwhile business and numerous companies are really mushrooming every single some other day with the sole objective of supplying web site hosting professional services. Without having better knowledge to carry out the entire factor of selecting a host you can easily end up with an extremely bad company. Right here are some of the tips you want when comparing our services:

The Price

This might be one such important aspect to appear at when considering web hosting services. You will want to evaluate different hosting price tag plans for unique services. Though it is important which you do not merely evaluate the cost solely, but you additionally think about various other factors. Always attempt to think about precisely what you will need from all the business very than just bouncing upon one with the price point.

Do They Really Cater For Growth?

Not every single internet hosting company is suitable for everyone. There are a few which have a good sharing provider whilst the couple do not have any sort of account for fasts growing companies. Because such, should you decide select this type of web hosting but an individual are a growing company you could have a significant difficulty when considering updating your internet provider. It is important to look into the niche of a particular business when which makes the comparison.

Technical aspects

As soon as you are looking at different web hosting provider providers with the sole purpose of comparing them, it is important that you evaluate the technical aspects. For example, you ought to consider the main reason which you need the web hosting provider. Do you ought to host a blogging internet site, a wealthy content website, e-commerce website or perhaps a movie site? This is going to make you have to consider the memory a specific business offers too as the storage as well as other this kind of aspects.

Technical assistance

This excellent is also the important account to make whenever comparing a hosting provider. You ought to physical appearance at just how responsive all of the companies are. Exactly how long does it take for the company to {respond problems like the downtime of the site, can you discover a person on the internet if you feature a problem. A company that has a range of technical help platforms is just good to go for. This system must include a toll-free call line, e-mail, and also alive chat.

Accessible features

Also as to make a comprehensive comparison stuck between companies you will likely require to consider the particular features that one offers. Exactly what "icing with the cake" do you receive from a business which does not appear from the others? Our include features like regular backups, several data centers, and additionally complimentary private domains. In many cases the hosting services will offer an individual with more than simply the webserver.

Owner interfaces

It is even important to consider the user interfaces that each web site hosting business offers. You will want to be keen on this because some offers may have good looking interfaces that are extremely challenging to use.

As such our are really just several of the numerous aspects which you have to think about when appearing at just web hosting providers.

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Small Wonder Computers

When we think of computers, normally an image of a PC or a laptop comes to our mind and it is a very instant thought, apart from the football sized primitive computers of the 1960s and 70s that also knock on the doors of our mind. But the image of small, yet powerful, single board computers rarely comes to our mind even if someone who has been asked this question is sitting right in front of it!

Now the question is, what is a single board computer? And is it different from the modern PC that we use on a regular basis or, for that matter, our very own friendly laptops? The single board computer is a computer build on a single printed circuit board with microprocessors, input/output (IO), memory, clock, and other features that are generally there in a normal computer. It has everything that any other functional computer has but at half of its size and almost double its speed. It closely resembles the motherboard of a PC but it has all the elements of a basic computer within its small periphery. this technology that is a single board computer has been used since the early 1980s in the industrial sector and in manufacturing computerized products. This technology was used to make high end technical products. The application of single board computers has its history. It is used as an application to many devices that we see even in our day to day lives but of which we’re not completely aware.

They are also commonly referred to as embedded single board computers. It is called embedded because it is used in manufacturing everything from airplanes and rockets to toys and even high end athletic shoes. The computer is a very powerful device if used along with some other electronic device. it is so powerful that it increases the efficiency and functionality of the device almost three times but the size of PCs and other normal computers does not support this application. It is for this reason that SBCs were invented. They have all the elements of a basic computer and because of the availability of these features within its small design it easily finds a place within some other device. And because of this application we are unaware of its existence.

Almost all devices today use a computer application - be it a fax machine, our very own indispensable mobile phones, cameras, and more; all use the embedded PC or SBCs. It takes less space and is also economical. However, before using this application just keep in mind its application necessity and cost, because normal SBCs do not always support all kind of devices and functionality; in some cases, special SBCs are required.

http://goarticles.com

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