Thursday, May 5, 2016

Computer screens: Glossary

DVI (Digital Visual Interface)
This interface is capable of handling the same video signals as HDMI. It does not allow, however, to process the audio portion of the signal. Although one can find some TVs equipped with this interface, it is typically reserved for monitors. Compared with VGA interfaces that long equip computer monitors, DVI input allows, provided your video card has a digital output, to transfer the video signal from the computer screen without use an analog conversion. The last tests we have made have clearly shown us that a digital connection between the computer and the screen significantly improves the picture quality (compared to the same image obtained via VGA analog input).

HDCP (High-Bandwidth Digital Content Protection)
Protocol to protect against copying high definition content. It is thus necessary to view a high-end definition image, for example, a Blu-ray DVD, the entire chain, graphics card, display ... is also compatible and supports HDCP.

HDMI (High Definition Multimedia Interface)
This interface that supports many video formats allows, among others, to transmit High Definition and his associate, all in digital. It is found on all televisions mentioning the High Definition on Blu-ray players, or on set-top boxes for receiving high definition transmitted via DTT.

We find increasingly that interface on monitors, even if the DVI is still more common in the computer field. It seems doomed to more or less long term, to replace the current SCART.

The term "resolution" here is a little unfair, this is actually the number of cells making up the LCD screen. It is generally given as the number of columns by number of lines (eg 1680 × 1050). This native resolution also provides information on screen format. For example, 1 680/1 050 = 1.6 is the resolution of a 16/10 screen, very common format in the 22-inch devices.

Contrast ratio
They are generally called "contrast" the ratio of the luminance (data in candela per square meter) between two successive beaches. Manufacturers refer to as "contrast ratio" value of contrast when one passes successively from the lowest luminance level (black) to the highest (white). As for the response time, measuring the contrast ratio is debatable, the methods used are far from homogeneous. A parameter that is actually irrelevant and of little interest to select a screen.

Colour temperature
It provides an overview of the colored pattern of a screen. There is talk of a warm color when it hits the red (around 2000 ° K) and cold as it approaches the blue (15,000 ° K). It is not uncommon for instructors offer different color temperatures depending on whether one is working on Excel or Word, as we watch a movie or we play. These preset color temperatures are generally accessible through the video menu.

Response time
Through measuring the time required to switch from one black level to a white level and a white level to a black level, this criterion is supposed to give you an idea of ​​the fluidity that you are expect your screen. The response time is a bit of a "cream pie" and together with the contrast ratio, one of the arguments that any seller will shake under your nose to recommend a product over another .

The only problem is you never know how this test is performed and manufacturers' information is generally unreliable. The measures response times we have achieved are far from those announced.

VGA (Video Graphics Array)
This is not entirely accurate, but usually this term that denotes the analog input of a monitor (VGA is actually a transmission mode associated with a resolution of 640 × 480 pixels, not a plug). The VGA connector, which consists of 15 pins is available on all computer screens, even if they are also equipped with a DVI or HDMI. Note, based on our test results, the quality of the image from the VGA input (analog information) is still significantly worse than following a DVI or HDMI input (digital information).

Computer screens: the connection

An LCD monitor is simple to install: once connected to the computer, pressing the on / off button makes it ready to use system. However, there are different types of connectors, all entrenched behind acronyms barbaric. Here's a mini-guide to be noticeable in the cables.

All screens are equipped with a VGA (Video Graphics Array). This allows the transmission of an analog signal from the graphics card from the computer to the LCD monitor. This connector, which is getting old, gradually gave way to the digital inputs. These constitute a real "plus" because they preclude any image degradation associated with analog / digital conversions (using an analog VGA output forces the computer to convert the image in this mode, image that will then be converted to digital to be displayed on the screen - the process can only harm the signal quality). Thus, most screens also offer a DVI (Digital Visual Interface) or HDMI (High Definition Multimedia Interface). This type of connector to transmit high definition content, such as those emitted by a Blu-ray DVD player or a game console like Sony Playstation. Beware, however: for viewing HD videos (this does not apply to programs of the TNT HD), the screen also has to be certified HDCP (High-Bandwidth Digital Content Protection). One point that moviegoers should check.

The locking high definition
HDCP (High-Bandwidth Digital Content Protection, for "protection of digital high-definition content") is a protocol developed by Intel (particular) to protect content in high definition against copying. To exploit this specification owner, the manufacturer pays a license. Specifically, to fully enjoy the high definition pictures, all devices used in the processing chain must be compatible. This is the case for projectors, Blu-ray players, TVs. And, increasingly, for computer monitors. We must check this if you plan to connect your display with a Blu-ray player or Sony Playstation games console kind. Indeed, if one link in the chain is not HDCP compliant, the HD signal will be degraded or even ... unusable. In this case, curtain on the screen: it desperately remain black!

Decryption: Other external hard drives

Beside the hard drives of desktop and laptop, manufacturers offer other models that can be very practical as multimedia hard drives, network drives, those with flash memory or online storage spaces and solutions cloud.

The multimedia hard drives
They allow viewing photos or videos directly on a TV, or listen to music on a stereo. The computer does not need to read these files. Most are also equipped with a remote control, very convenient to launch a movie or slide show without leaving the sofa. Some wi-fi models can even wirelessly transfer files from a computer hard disk.

Network hard drives
Simply connect these models "NAS" (Network Access Storage) box to its Internet service provider to be able to transfer files or access the content from any computer connected to the home network. Thanks to them, it is also possible to view your photos or listen to the songs in his nightclub from any computer with an Internet connection, without having to take the drive with you!

Flash memory drives
These devices called SSD (Solid State Disk) are primarily designed to better withstand shocks than conventional models. They also have the advantage of offering shorter access times and lower power consumption. In contrast, the number of disk writes is limited (a few hundred thousand anyway) and their capacity is limited to 256 GB. They are also a little more expensive to purchase.

Online storage spaces
Many websites offer space online storage that can save files (videos, photos, documents ...) and then access them from any computer connected to the Internet. The basic package, usually limited to 1GB is often free. It must however pay to get more storage space and / or additional services.

Personal clouds
In recent years, hard drive manufacturers have stronger competition online storage solutions (Dropbox, Skydrive, etc.). The cloud is now democratized. To stay in the race, so some clouds offer "personal" (Western Digital My Cloud, Seagate Central). These hard drives of large capacity enough (2, 3, 4 TB), which connects to the Internet via the box of the home. One can store their documents, photos, films or music and view them remotely from a computer, a touch pad or a smartphone . Everything is recorded at home, not on servers located enigmatic nowhere on the planet. The downside: saving files is your responsibility, and if you lose the disk (during a burglary, for example), you lose your data.

Hard drives are formatted by default in either FAT32 formats (File Allocation Table: file allocation table) or NTFS (New Technology Filing Systems: native file system). FAT 32 is suitable for all computers (Windows, Apple, Linux), but the size of the files copied to the disk can not exceed 4 GB. For larger files, you must reformat the disc (operation that erases data) NTFS. But then you can not use your disk with a Windows PC. On a Mac, you can read files, not add. Be aware that it is often possible to allocate space to each format on one disc.
To reformat the drive, two solutions: use the software provided by the manufacturer, who will guide you, or directly from Windows. Access the disc options (right click when the disc is selected) and click "Format Disc". Attention This deletes all data on the disk.

External Hard Drives: Five Rules to Keep Your Files Safe

Photos to family videos, conservation of digital files is not to be taken lightly. If external hard drives can be useful, they are not necessarily enough to save your documents. Our advice to limit the risk of loss.

1. Make regular backups
- Transfer files to an external hard drive is a breeze. Just the "copy" and then "paste" them in a folder on the device. However, take care not just "move" files, but out the "duplicate". It is only then that you will have an actual copy that you can recover if the original file disappears.

- Some manufacturers provide their software appliances that facilitate the transfer of data or to configure the computer to automatically create on the hard disk new files backup.

- You can also store his external hard drive "system backups." They are genuine photographs of the computer, which will facilitate the resettlement programs in case of full crash.

2. Avoid shocks and jolts
To keep its data as long as possible, they must have been properly recorded. This is the basis. However, external hard drives are fragile machines that fear the shocks. Avoid moving the hard drive during the data transfer phases. It suffices a blip for the playhead comes to scratch the wafer, which may cause data loss. These devices are not designed to withstand sharp falls, and even if the portable models are stronger than their desktop counterparts, they are not unbreakable. Install your hard drive on a flat surface where it will not be rushed. For backpackers, more resistant devices with shock absorbers and flexible shells exist.

3. Take care of the hard disk
- Hard drives do not like the heat. Install yours away from direct sunlight, so as not to subject it to too high temperatures that could damage it prematurely. Note: If a device is hot, this is not necessarily a bad sign. "We provide increasingly our metal shell models which reflect heat outward , explains Minh Le, LaCie Marketing Director. In touch, the device looks very hot, but the interior is protected. "

- Avoid overfilling your hard disk: overburdened, it will be less reliable. And, of course, be careful not to disconnect during file transfers.

- If you add and erase files, you can occasionally perform a defragmentation. This operation, which consists of a reorganization of the files on the hard drive will improve its performance.

Good to know. Despite all these precautions, an external hard drive is not eternal. Its average life is 5 to 7 years, and there is nothing to know precisely when it will fail. "Either way, users will certainly renew their equipment before both the storage capacity and transfer speed qu'affichent today their devices appear weak in a few years' , predicts marketing Director of LaCie.

4. Vary the backup media
If it is well suited to temporary storage, external hard drive is not ideal for storage of long-term data.

- To keep your data as long as possible, burn to DVD or Blu-ray discs, at average speed. Make sure that the recording was done correctly, and store the disks in a housing protected from light, humidity and sudden changes in temperature.

- It is now possible to keep their data online via the cloud . Providers (Dropbox, Hubic, iCloud, Skydrive, ISPs, etc.) generally offer the first gigabyte of storage. For more ability you have to pay. Also, some external hard drive manufacturers and some Internet service providers make available to their customers online storage space.

5. Check your copies
- Whatever backup method chosen, regular monitoring is required. Check occasionally that the files can be opened. An external hard drive must be restarted regularly, otherwise seize definitively.

- If your hard drive external, some documents have defects, it is time to copy all of the new media. If you have the original file, save it again. Otherwise, try transferring it to the computer. If you get there is that it did not contain an uncorrectable error. It remains only to save it again.

How to Buy External Hard Drives?

External Hard Drives
Increasing capacity, increasing throughput

Simple to install and more affordable, an external hard drive is an interesting solution to extend the storage space of a computer. Whether mobile or destined to remain on a desktop, network accessible or not, or is not capable of playing media files ... To each to choose according to their needs.

Photos, videos, music, games, software ... digital data accumulate so rapidly that they sometimes feel cramped in the hard disk of a computer . An external hard drive can be extended simply and at reasonable cost, storage space. Just connect the device to the computer to be able to burn data.

Or laptop
A desktop hard drive is relatively bulky and can weigh over a kilo. These memory units are not really mobile products, even if they are transportable. Their storage capacity ranges from 750 GB to 8 terabytes (TB)  1 for prices ranging from 130 to more than € 600. Not to be confused with the "buffer" memory (or memory "cache"), 8, 16 or 32 MB, which serves to optimize performance (and does not constitute a selection criterion).

The size of the plates that make up serves as their generic name: it comes to hard drives 2.5-inch and 3.5 inch. The rotational speed of the 3.5-inch hard drives today reaches 7200 rpm (rotations per minute), which ensures a good flow of writing and reading data. This performance, however, obliges manufacturers to integrate a power supply, which forced to have an electrical outlet nearby.

Lighter (around 200 g), and thus more suitable to transport, portable external hard drives have, themselves, of 2.5-inch platters. They offer smaller capacities from 500 GB to 2 TB, for prices ranging from 50 to 200 €. Their trays currently running at a speed of 5400 rpm, providing de facto a slightly lower rate than "fixed" disks, but it avoids the mains connection during use: the connection to the computer, via USB or other sufficient.

There are also portable hard drives wi-fi, to extend the storage space of a smartphone or a touch pad . The wi-fi makes it possible to connect the hard drive to the smartphone or tablet, after which the user can copy its files in both directions, since an application downloaded from online stores App Store (Apple) or Google Play Store (Android). File transfer is however not as fast as a wired connection. Note that you can also play back files (music, for example) on your phone, wi-fi, without copying them.

A housing to save money
An alternative solution is to buy an internal hard drive and slide in a housing, bought parallel. There are both formats (2.5 and 3.5 inches). Performance is similar, but the cost for the use can be more interesting, especially for users, handling large data volumes, juggle multiple hard drives. It takes between 20 and 50 € for a housing and € 100 for an internal hard drive 3.5-inch 2TB. An equivalent external hard drive is priced around € 150.

The future is USB 3.0
The connection present on the hard drive is very important: it is from this that depends on the speed of data transfer to and from the computer. All models feature a USB 3.0 connector, which offers speeds (theoretical) 600 MB / s, 10 times faster than USB 2.0. Firewire and eSata ports, by contrast, are declining.

Quiet and airy
An external hard drive office, usually on permanently, should not make too much noise in operation. The hum of some models equipped with a cooling fan can become very annoying after a few hours.

In order to put the best external hard drive on the workspace, provided cables should be long enough. A meter appears to be a minimum for a connection with a computer under a desk. Manufacturers tend to generalize the brackets for placing hard drives vertically. On a desktop, the space savings is obvious, even if the tipping risk is greater. With or without a fan, the models 'bodywork' aluminum are generally more expensive, but provide better cooling of the hard drive. They are intended for prolonged and intensive use. For occasional use, a plastic casing enough.

Multimedia Hard Drive ...
One commercially-called hard disks "multimedia", which allow course to store files, but also know how to read. Simply transfer photos, videos, or its files MP3 to disk, and then connect it to the TV or the stereo for viewing (or listening). Common compression formats are generally supported (MP3 and AAC for music, DivX video, JPEG, BMP and sometimes PNG for images). One tip, if you have a flat screen: Make sure that the disc has an HDMI socket to enjoy high definition images. Moreover, the presence of an antenna on the housing indicates that the drive is compatible wi-fi: there you can drop files from your computer wirelessly.

... Or disk "network"
Finally, there are hard drives "network" (NAS, Network Access Storage), which can be shared between multiple computers by connecting to a router. Like any network element (computer, but also shared printer, for example), this type of hard disk has an IP (Internet Protocol). Multiple computers can access through an Ethernet connection, or wirelessly via a Wi-Fi network. A management interface typically used to configure its settings (access rights, etc.) from their computer. 500 GB to 2 TB capacities are variable and partly condition their price, between 100 and 600 €.

HDD to personal cloud

In recent years, hard drive manufacturers have stronger competition online storage solutions (Dropbox, Skydrive, etc.). The cloud is now democratized. To stay in the race, so some clouds offer "personal" (Western Digital My Cloud, Seagate Central). These hard drives of large capacity enough (2, 3, 4 TB) that connects to the Internet through the box of the home. One can store their documents, photos, films or music and view them remotely from a computer, a touch pad or smartphone. Everything is recorded at home, not on servers located enigmatic nowhere on the planet. The downside: saving files is your responsibility, and if you lose the disk (during a burglary, for example), you lose your data.