Offline Control

An important aspect of kids’ computer usage is the amount of time they spend in front of the screen. A limitation and control of kids’ computing time is vital to avoid future addictions, and let’s face it, kids need to play with real toys, exercise, and so on.

timekpr is a program developed to track and control the computer usage time of a system’s accounts on a daily basis. It allows this limitation to be set both as a “green” period of the day (setting a period of time in which that specific user may use the system) and/or as an amount of hours per day. Unfortunately, timekpr is not available for ubuntu 11.04+ yet, even though its creators expect to provide a new release by August 2013.

Controlling Internet Usage

Surfing on the web requires lots of care and responsibility even to adults. Kids are curious and have a natural tendency to explore, so it is no wonder that they end up visiting dangerous or less appropriate websites (not only in a content point of view, but also dangerous to the system’s security). In order to prevent these kind of situations, there are several programs available, usually called “parental control” programs.

Gnome Nanny will help with parental control in Linux and is probably the most well-equipped and user-friendly program available. Specially directed to infant control, it helps define separate rules for different users. It has a tabbed interface divided in “PC use time”, “Web browser”, “Mail client” and “Instant messaging”.

The first feature presents the same functionality as timekpr, so if you want a full suite, Nanny is probably better to fulfill your needs. The second feature is probably the most important, giving the possibility to establish which sites are forbidden and which allowed, either by hand or by downloading lists available online. As far as the site informs, the latest (and unstable) Nanny version was released back in 2010, so its development probably ended back then. It is also reported that Nanny works only with three browsers, Epiphany, Firefox and Konqueror, so if you use other browser I recommend that you test Nanny’s effectiveness.

DansGuardian is another program, this one designed for web content filtering, using several methods such as phrase matching and URL filtering. It is also more tailored for running on servers, which is specially useful for schools, libraries and such. The great advantage provided by DansGuardian in comparison to other software is the previously mentioned filtering through phrase matching; sometimes pages with bad content do not have addresses revealing such content. DansGuardian searches pages for “bad” words such as “hate” or “pornography”, providing a much more effective content filtering.

Finally, WebContentControl is a different kind of program, since it is made to, with its GUI, take control and help users configure other programs – specifically, DansGuardian, FireHol, and TinyProxy. Besides controlling these apps, it provides an easier way to start/stop filtering, backs up configuration files, only changes what is really necessary, and provides SSL filtering.

Now, back to you, how do you configure your computer to restrict Internet access for your kids?

Image credit: Baby With Notebook Portable Computer by BigStockPhoto

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The origin of Bitcoin

Created in 2009 by the Japanese pseudonymous developer Satoshi Nakamoto (it is not known if, behind this pseudonym, was a person or a whole group), this currency is a free open-source project based in the peer-to-peer technology, with all its issues and transactions being carried and managed by the whole network instead being centralized, as happens with the regular currencies. This means that, if you want to be paid by a friend living in the other side of the world, that payment made with Bitcoins will not involve any other entity such as banks.

How Bitcoin works

Just like Paypal where every account is associated with an email address, everyone transacting Bitcoin has at least one unique address, made by a set of regular characters. When your friend send money to you, the network adds your unique address to the Bitcoins and sends them to you; now you own that amount, while your friend is prevented from using it again by the network.

The scheme below represents this process, for a transaction of 2.00 BTC using more than one address.

Unlike Paypal that transacts in the physical currency, Bitcoin is the currency for the Web. Regardless which country you are residing, you have to own Bitcoin to transact in Bitcoin.

Managing your Bitcoin

To manage your Bitcoin and all its transaction, you have to use a software call “wallets“. There are various software available for multiple operating systems and platforms both as desktop (requiring installation) or web-based, which are required to be a part of the Bitcoin network. Your wallet generates your Bitcoin address, and through it, lets you send and receive Bitcoins from other users. It is basically your account manager – much like the regular e-banking services: you can watch your balance, the transactions you made, pay for services and goods, make transfers, and so on. Also, you don’t have to be online in order to be paid; the wallet software receives and holds your money in place until your next connection.

(There are actually real coins made, which are basically collectibles containing codes to be redeemed by digital Bitcoins.)

Earning Bitcoins

At this moment, you’re probably wondering how to gain access to Bitcoins. The first and easiest way is to simply buy them , and there are many places to do this. It is also possible to generate Bitcoins. That’s right – growing money!

Mining Bitcoins

This process, however, is much harder than it seems. Mining is a way to process and monitor transactions through the creation of blocks – permanent records of Bitcoin activity and new Bitcoins. Whenever a block is created, an ever-decreasing (halving every 210K blocks) bounty (in BTC) is awarded to its creator, and that block gets in line with other blocks, thus forming a blockchain. In order to perform the mining process, you need the right software and hardware. Since the mining rewards (this is the number of Bitcoins generated per block) are always decreasing, the number of Bitcoins in existence will never exceed 21 million. In this graph, you can watch the evolution of the total Bitcoins in circulation, which is still under 11 million.

Some concerns with security might arise, like in all other online payment methods. Even though all Bitcoin transactions are stored publicly, available for anyone wanting to see them and providing information such as one’s balance and address, it is not possible to associate such data to its physical owner. This means that, unless you publicly display your Bitcoin address, no one will know that it belongs to you. However, to improve security, it is suggested that users create a new address every time they make a transaction and that they hide their computer’s IP.

There are many ways in which you can use Bitcoins, both online (art, web hosting, design, e-mail services, security services, software, and many others) and offline (auction sites, toys, clothing, electronics, consumables, books, music, and even professional services). In fact, more and more stores and professionals are accepting this currency as payment. It is safe to say that Bitcoin, like nearly every Internet-related creation, is shaking the actual society.

It was recently reported that Bitcoin value has reached $1 billion, which is too much to not take into account. Since Bitcoin is not related to any institution or government, it tends to be safer than the usual currencies that are tied to current economy in crisis. However, it is important to highlight that the Bitcoin world is still in development, so it is not possible yet to know the true potential and effects that Bitcoin might have in our lives.

Do you think that Bitcoin might succeed? Can it represent the future of our Economy, or is it just another bubble waiting to be burst? Let us know in the comments.

Image credit: Stack of bitcoins isolated on white by BigStockPhoto

The post MTE Explains: What is Bitcoin And How You Can Utilize It Online appeared first on Make Tech Easier.

1. Internal Sound Cards

The vast majority of computers (laptops, at least) come with not-so-good sound cards which, despite doing their job well for the regular user, are far from being the best cards for people who are into music. Before buying a new computer, check the quality of the included sound card. If you have already bought a new computer and wish to get a better sound card, there is always the possibility to change yours for a new one (warning: if you are not certain on how to do this, DO NOT do it. Not only is it a hard process, especially for laptops, it can also void your warranty).

Most of the best best internal sound cards in the market are made by ASUS and Creative. The ASUS Xonar Essence STX is considered to be the best, followed by the ASUS Xonar Essence ST9 and the Creative Sound Blaster X-Fi. They all cost between $150 and $215, and they are considered to be “professional”. In fact, the ASUS models do not have any regular 3.5mm jack ports (but they do come with an adapter), while the Creative one has two such ports.

2. External Sound Cards

External Sound Cards are useful for those who are not able to add an internal sound card to their system. It can be due to a lack of PCI Express port or the laptop casing is not removable. In this category, there is a wider spectrum of products to cover. There are several ways of connecting these devices to our computers, such as USB or FireWire. The external sound cards use these interfaces to communicate with computers and improve its sound reproduction capabilities. They also come in many different configurations, from USB sticks to devices looking like external hard drives, and different prices, from $10 to $1000.

Once again, Creative comes as one of the most reliable brands in this category, with its X-Fi series (Sound Blaster X-Fi HD, Sound Blaster X-Fi Surround 5.1 Pro and Sound Blaster X-Fi Go! Pro). If your budget is lower, there are plenty of other options from lesser known brands that will also do the trick. I have one of these “USB sticks,” and I guarantee you will notice the difference, because they emulate a 5.1 card (and they do not require an existing sound card since they work completely independently).

3. Headphones and Speakers

If I said the external sound card market was really big, this one is gigantic – earphones, headphones, regular speakers, surround speakers, cordless, you name it. And since they are the last devices the sound gets through before reaching your ears, they obviously have some influence in playback quality. They also come in many colors, models and prices, so ultimately this is just a matter of taste and/or budget. According to Lifehacker, who polled their users for the best earbud, headphone and speaker, the respective favorites are the Shure SE215 Sound Isolating Earphones ($100), the Grado SR80i ($99) and the Klipsch Promedia 2.1 ($150).

What are your favorite ways to improve audio experience? Let us know in the comments below.

The post How to Hardware-Boost Your Audio Experience appeared first on Make Tech Easier.

The differences between Analog and Digitial sound

Even though man has the ability and the means to record sound, that record will never be an exact representation of the original sound.

The following image shows the waveform for analog and digital sound wave. As can be seen, the analog sound wave (1) is rather different from the digital one (2).

The analog waveform is continuous and have successive crests and troughs that represent highs and lows of our voice whereas a digital waveform is like a barchart where the highs and lows are represented as number. The quality of a digital sound wave is often linked to its “sampling” rate. CD has a quality of 44100 samples per second (44.1 KHz), which is a quite good representation for our ears.

Lossless vs Lossy

There are two different kinds of digital audio file formats – the lossless and the lossy. As the name suggests, the lossless file is made without any losses relatively to the original tracks. For example, when you rip an audio CD to your hard drive in lossless format, the files you get are the exact same tracks contained within the CD. However, if you select the lossy format, some information that is unnecessary for the listener, such as sounds that we cannot hear, are discarded.

Lossless formats include WAVs, FLACs, AIFF, and Apple Lossless. Inside this group, the first two are probably the better-knowns.

Inside the lossy formats, other than the popular MP3, we still have WMA, AAC, MP2 and OGG. The main difference between these formats is the multiple encodings technology used.

There is still another thing to consider: whether the format has a variable (VBR) or constant bitrate (CBR). Some formats have variable bitrates, since they use higher bitrates for complex segments of the file, and lower for the other segments. VBR formats have a better quality-to-space ratio, compared to CBR ones. Even inside each format, there are different kinds of bitrates. For example, MP3 is usually found in V0 (~245 kbps), V2 (~190 kbps) and 320 kbps.

The Size Issue

If you have noticed, FLAC files are usually much bigger than the MP3 ones (usually about 10 times bigger). This is because their bitrate is higher. “Bitrate” is the amount of information processed per second whenever you play a file. So, the higher the bitrate, the higher amount of information will be processed and the better sound quality will be presented (the same happens for images and photos). In this case, a sound file created with a higher bitrate (such as FLAC) will be bigger in size than a sound file with lower bitrate (such as MP3).

In the above image, I compare 2 folders from my music collection: the first is a FLAC album, the second is an MP3 (128 kbps), and they have, respectively, 14 and 13 songs plus the album cover. As you can see, the FLAC album is much bigger in size than the MP3 one. Lossless formats such as FLAC give a better music quality, but they take up much more space than the lossy ones.

Which audio format is suitable for you?

There are many factors that can affect which format you should choose for your music:

• If you have plenty of storage space, be it offline or online, you will want to go for the lossless format (such as FLAC).
• If you are an iPhone, iPod or Mac user and you purchase your music from iTunes, you are mostly stuck with AAC.
• If you purchase music from Amazon or any other source, you will be mainly dealing with MP3.
• WMA is a proprietary format by Microsoft. It is usually smaller in size (than MP3), but not well supported in other platforms.

For MP3, the 320 kbps files are really the better ones, but again a regular person won’t tell the difference between those and the V0 ones. A regular V0 album with about 15 songs is about 65 MB in size, so I personally believe that V0 (VBR, if possible) really is the best quality-to-space ratio option for your music collection.

Is this article helpful? Let us know in the comment.

The post Understanding The Differences Between the Various Audio File Formats (and Which One Is The Most Suitable for You) appeared first on Make Tech Easier.

1. File naming procedure

First, you should establish your own nomenclature for the files. It does not matter so much how you do it, just each new file you add to your collection should follow the same format. For example, I use “01 Song Title.mp3″, which is the number of the song according to the album’s track list, followed by the title of the song. I always capitalize the first letter of each word.

2. Get the right album cover

The next step is to download the album’s cover as a decent-sized JPEG. Name it “folder.jpg” and store it inside the album’s folder. Naming the cover “folder.jpg” works for two things. First, it is a trick that works in every Windows folder which adds that specific image to the folder’s icon. In addition, many music players fetch the album’s cover searching for a file named “folder.jpg” inside the directory holdings the music files. Your collection will become attractively organized, and your player will be more effective fetching the album’s cover.

Apparently, Windows Media Player 11 messes up with these “folder.jpg” files, marking them as system read-only files, which hides them from Windows Explorer. Here’s the fix:

1. Open a command window

2. Change directory to the root of your music library (using the “cd” command)

3. Type in the command below:

attrib -s -h folder.jpg /s

This should make the folder.jpg visible again.

3. Fixing the tags

The next step is to organize the tags for the files. Windows itself provides you the tools to do this (right-click the file -> Properties -> Details tab), but it is easier to do this in a bulk way, using a third-party software. I use “Mp3tag,” but there are many other options. Tags that you will need to edit include the “Title,” “Artist,” “Album,” “Year,” “Track,” “Genre” and “Comment” tags. “Artist,” “Album,” “Year” and “Genre” are the same for the whole album, while “Title” obviously varies with each song.

Very often, the albums come with the “Track” tag in a form like “1/10″ or “07″; I like to use a singular number – 1, 2, 3 and so on. Finally, I always delete the contents of the “Comment” tag, as it is simply not useful. I also add the album’s cover to the files using Mp3tag. If the files already have a cover assigned to them, I replace it with the “folder.jpg” image I discussed earlier.

If you follow all these steps, it is very likely that your digital music collection will become more enjoyable while browsing through it. Additionally, the issues inside your music player will be reduced.

Do you have another way to organize your digital music? Let us know in the comments below.

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