Key USB

Description and operation

Keys USB are supplied in energy by the connection USB of the Ordinateur on which they are connected. Keys USB thus do not contain a batteries. They are insensitive with dust and the stripes, contrary to the Disquette S, the CD or DVD, which gives them an undeniable advantage on the level of reliability. The current keys are in format USB 2.0. Keys USB are relatively standardized, however, some are not compatible with some operating systems, requiring the installation of a pilot.

The capacity of a key USB can vary some Mégaoctet S with some Gigaoctet S. At the beginning of 2007, the most popular keys have 1,2 or 4 gigaoctets, and up to 16 gigaoctets for most expensive. The real capacity is slightly lower than that which is announced (see explanations) .

One finds now keys USB based on minis hard drives (see Microdrive) . These keys post capacities even more important for more reasonable Prix. These keys are also supplied by bus USB. Compared to traditional keys USB, their flows is generally better but the access times are longer. They are also a little more fragile and can heat in the event of intensive use. Moreover, their size is slightly larger but they hold always easily in the pocket.

In theory, the memory flash is supposed to preserve its data during ten years . In practice, rare are generally those which do not know at least a person having seen weakening her key USB, on the level of FAT. Certain keys are coupled with:

a reader able to restore the musical files that they contain, in particular in format MP3, becoming thus miniature walkmen (key with pile AAA plus ear-phone weighs approximately 60 grams);
a tuner FM, with possibly the possibility of recording flow in the integrated memory of them;
a micro , the sounds which it collects being recorded in the integrated memory, acting then as Dictaphone;
an external indicator allowing to evaluate which Pourcentage memory is used.

One finds also keys USB in some multi-fonction pocket knifes.

It is frequent that a key offers two partitions, public and one whose access is subjected to a Password. The key can then contain, in full safety, of the confidential data which one makes a point of keeping under the hand (parameters of connection Lotus Notes, wallet of passwords, Email, etc).

Compatible operating systems

Windows starting from its version ME (Millenium) as a native (the use of a key USB requires the installation of a pilot under Windows 98 SE)
Mac OS 9.1 or higher
Linux with an after core 2.4

If the Firmware allows it, certain computers have the possibility of starting a distribution '' Live '', i.e. a achievable Operating system since a removable support, starting from a key USB, with the image of Shinux, Flonix, Damn Small Linux or Mandriva Flash.

When the firmware does not allow it, one circumvents the problem while starting since a CD-ROM containing pilot USB allowing in their turn a emulation of starting on the key (see for example Flonix ). This handling is not possible that with a Bios or a EFI, and not with a Open Firmware.

Inside (64 Mo)

Comparison with the others Mass memories

It is interesting to compare keys USB with the others mass memories like the Disquette S, the discs ZIP and the CD/DVD gravables and regravables. In spite of their popularity in fall, diskettes 3 ½ inches and the discs Iomega Zip are still available on the market.

The diskettes today are used very little because of their low capacity (1,44 megabytes) and of their slowness. The diskettes remained a long time the most popular means of outvessel fuel storage of the files, but more and more of computers are sold without disk drive. On the contrary, very few computers are delivered without interface USB. Keys USB are quite simply faster than the diskettes, contain more data, and do not require a specific reader. If the diskettes did not disappear yet, it is mainly for their facility of use with old operating systems (like Windows 98, which requires the installation of pilots for the use of a key USB) and the facility of starting. The management of the USB is indeed complex, therefore relatively bulky in lines of code, and consequently, it is thus not present in all BIOS.

Key USB and integrated softwares

With the increase in capacity of keys USB, it is now possible to install Logiciel S on a key USB and to move everywhere with its data and its software preferred.

Web sites thus start to propose “packs préconstruits” paying software or free in version installables on a key USB. For example:

Framakey proposes packs of free software, modified by their community to function on a key USB.
Portable Suite Hist-Géo proposes a selection of 80 essential, free software and freewares, classified by topics and functioning on a key USB. Many directed tools are included Histoire - Géographie - Cartographie. Together free in free remote loading. No installation: the software is ready to function.
ClefAgreg is an equivalent for Mathematics. It is an autonomous key USB with a panoply of free software dedicated to Mathematics (Scilab, Maxima, Giac/Xcas, Pari/GP,…), it comprises the free software used with the aggregation of Mathematics (oral tests, Camllight including for the test of data processing of the option D). Built starting from Debian Etch, it directly can booter or using CD for the too old computers.
Freewaooh MoveSoft is undoubtedly the compilation of the software (free and freewares) most complete. Office automation, while passing by the programming or CAD, it is more than 60 software which is embarked there.
LiberKey the portable compilation of (free software and freewares). It gathers more than 200 directly achievable software without any preliminary installation and all holds on a key USB of 512 Mo.
One can also install a distribution Linux on key USB, it is enough to extract the ISO from the Live CD on the key and to return it bootable.

Appearances

In the emission televised Hello Land the , created and presented by Thierry Ardisson, this last launches the vidéos by connecting a key USB to a hub. It is this connection which, in governed, starts the launching of the recorded subject.
Recently, certain artists use key USB like support for their albums: Bubblies.
on September 27th, 2007, at the time of the Grenelle Environment, in fact keys USB were selected like support for the report/ratio of: 1000 pages which was given by the six work groups to the Minister for ecology French Jean-Louis Borloo, this in manner symbolic system, in order to show that, by respect for the environment, it is necessary to save the Papier.

See too

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