All about SD Memory Cards

“It seems incredible that a piece of plastic so small to be able to store as much information”. Most likely is that is the thought that crosses our minds every time we have in our hands a memory card. This reflection has, of course, a good solid grip. Those who that remember the old diskettes, with its huge size and its 360 Kb. of capacity, knows the hardships they suffered whenever had to store something that occupied more of this limitation.

Of course the computer at that time was much simpler, and scenarios to need more of that capacity, limited. But since those days until today, technology has advanced, allowing the creation of increasingly precise and complex instruments, and with them came the need to store the huge amount of data they generate or they need to function.

All about memory cards

It is currently not possible to think about to buy a device without accompany it with its corresponding SD memory card. We’re not just talking about digital cameras, but also video cameras, MP3 players, PDAs, GPS, smartphones, tablets, TV Box and many other electronic devices, each with its corresponding type of memory card. Therefore it is good to be informed about the various options that exist in SD memory cards, information that can be obtained easily if continues reading this article.

While on the market there a wide variety of memory cards from different manufacturers and with many different purposes, such as Compact Flash, Memory Stick, MultiMedia Card and others, the truth is that the most popular format memory card is called card SD memory, acronym of Secure Digital, the which has very good references of all who use it daily, and that is why it has become a standard widely used, together to their “brothers” Mini SD and Micro SD, the latter being the most widespread.

All about memory cards

Main features of the SD Memory Card

Some interesting features found on SD memory cards are its small size and large capacity, as well as its compatibility with all kinds of devices, points that will explain below in the article.

Formats SD memory cards

The format is asymmetrical, therefore no risk of being inserted by mistake on your computer, besides having a good small size:


Traditional SD Memory: 32 mm x 24 mm x 2.1 mm
Mini SD memory: 20 mm x 21.5 mm x 1.4 mm
Micro SD memory: 11 mm x 15 mm x 1 mm


Storage Capacity SD Card

The SD memory card offers different storage capacities: 8, 16, 32, 64, 128, 256 and 512 MB, although such cards are hard to find, as they have been replaced in the market for cards with much greater capacity: 8, 16, 32 and 64 Gb, and until they can even reach up to 128 Gb. of storage space. It is important to remember that not all computers have support for cards with 2GB or more, due to the difference in formatting (sometimes the problem is solved by firmware upgrade that computer).

All about memory cards

First, it is important to decide the storage capacity of the memory card. But we should not get a wrong idea, because the capacity bought never enough, much less in the camera of a teenager who is on vacation!

The fact that digital cameras offer more and more megapixels without increasing the price, creates the need for more memory to fit the photographs, a higher definition occupy more space.

All about memory cards

Card compatibility SD, MiniSD and MicroSD

In this sense, MicroSD type cards are more compatible than MiniSD and the SD type, perhaps because they are the most widespread type of memory market. Used by countless manufacturers of digital machines such as Casio, Canon, Nikon, Pentax, Kodak, Panasonic, Konica/Minolta and manufacturers of electronic devices around the world, are included with all kinds of devices like smartphones, tablets, PDAs, mp3 players and much others. However, if your device only accepts SD cards type, also called Transflash, this is not inconvenient to use, because in the market there are adapters that can convert a MicroSD or MiniSD memory card into SD type.

SD memory cards safety and security

The SD memory cards have a physical lock system which prevents the writing on the card, similar to the recording obstacles included in the old 3.5 diskettes, although the market we can find cards cheaper models without this feature. However, unlike diskettes, this blocking is performed by the firmware of the device detects that the key is activated.

The card contacts are placed in a depression of the card, so as to avoid contact with the dirt left by hands and other materials.

All about memory cards

Memory cards speed

Memory cards can have different transfer rates (which also varies in price), according to the version used. Speed is measured in multiples of 150K (equal to CD-ROM). The most usual is to find cards or equipment that use up to speeds of 16x (2.4 MByte / sec), and some faster than 66x (10 MByte / s), although they can also be ultra-fast 150x or even 133x cards.

In fact, many times the speed and capacity to transfer data to the computer of these cards can only be exploited if we have a USB 2.0 port. However, if you are thinking of using more advanced equipment and professional semi-professional camera, or SLR, will certainly better benefits in the use of faster memory cards.

Memory card peed table


4x: 600 KB / s
16x: 2.4 MB / s
32x: 4.8 MB / s (SanDisk Pro)
66x: 10MB / s (SanDisk Extreme, SanDisk Ultra II)
133x: 20 MB / s (SanDisk Extreme III, Lexar Professional)


Other functions:

Because of its great popularization, the SD Card Association, entity responsible for the standardization of this class of devices, defining today the new features and applications such as the ability to add a Wi-Fi device within the card itself, devices that can already be found in some electronics stores.

All about memory cards

Examples of such implementations are:

SD Card with Copyright, used for film distribution, which allows the user to purchase an SD Card containing a DVD movie format, which can be played on computers and portable devices like PS3.

Using SDIO technology, which allows, using the dimensions of the card and using their pins, the use of devices such as Bluetooth and Wi-Fi receivers, among others.

While this format is here to stay, there are significant differences in features, capacity and price. It is therefore necessary, before buying, learn more to better select the model that will bring the expected result in our equipment.

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USB dongle types: Wi-Fi

As we know, a dongle is a small hardware device that connects to another device to provide it with additional functionality. Over the years, the dongles have become one of the main tools for better job flexibility, since they offer important features that otherwise we could not be used.

As proof of this, the dongle USB devices have not only become one of the most used for storing digital files means, but also constitute a really interesting option to transfer information between computers and peripherals, as well as to share the network connection.

USB dongle types

Thanks to its capacity and effectiveness, USB dongles have become one of the best alternatives for storing files, even replacing other media, such as optical disks.

However, as we mentioned above, dongles not only serve to store files. There are also different types of USB dongles, such as those that let you add extra features to computers to use wireless Internet access, thereby providing wireless connectivity to the network.

Consider that many desktop computers do not have this type of connectivity, so they must be incorporated in an internal Wi-Fi card, while in some laptop models this type of functionality is obtained by external gadgets.

USB dongle types

Therefore, often the best solution is to opt for a USB dongle for Wi-Fi, which currently can be found in the market in variety of models, whose function, once connected to the PC, will be to locate nearby wireless networks in order to share access.

Overall, one of the most popular models of USB dongle for Wi-Fi, so-called Wi-Fi scanner, it is one that has shaped USB key, which gives users the ability to search an access to connect to Internet.

This type of USB dongle has a set of LED lights, which are lit without the computer, either desktop or laptop, it is on. The lights will indicate whether it has detected the presence of a wireless network.

USB dongle types

Some models even feature a series of LEDs that indicate the signal strength, thereby allowing us to know at the time if accessibility is increasing or not. In addition also they include different colors of LEDs that specify whether the network is encrypted or not.

We can also opt for the possibility of creating a personal wireless network through a USB Bluetooth dongle, which allows us to connect various digital devices to each other without the need for wiring.

In this sense it is important to highlight the importance acquired in recent years the use of Bluetooth, technology is making strides, and because of its powerful features are increasingly portable devices that have this type of platform.

USB dongle types

To learn more about USB we recommend reading this.

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What to do when we cannot eject a disk or USB memory

Undoubtedly Windows is currently the best operating system which can give life to a PC. Especially after the appearance of version 10. But despite all the advances in your code, the system can still become somewhat capricious, and simple tasks such as disconnecting a flash drive or a memory card can become a nightmare. This article looks an easy way to get the system back us control over the storage units and devices connected to the computer.

It is a deeply rooted custom that when we completed tasks of copy, move or delete files or documents on a memory card, flash drive or external disk, we click on the device icon with the right mouse button to select the “Eject” option, for that the system disconnects the device and can remove the storage unit from the port without any later inconvenience.

How unlock files

For those who do not know, this procedure ensures that Windows ends all tasks is doing with the device, i.e. the operations of read or write on the files it contains. If we remove the device from the port without notifying the system, it is likely to corruption or damage occurs in the data files that are stored on the flash drive or memory card.

However, occasionally remove a device can become really complicated, the operating system sometimes prevents us from proper extraction, presenting a notification window with the following: “Windows can’t stop your ‘Generic volume’ device because it is in use. Close any programs or windows that might be using the device, and then try again later”, instead of the usual “Safe to Remove Hardware”.

How unlock files

If we face this situation, from this point we have at our disposal an interesting amount of tips that we can be helpful to solve the problem.

Ejecting a flash drive, external drive or memory card safely

Overall, one of the first things that can solve our problems is check that any program or file is accessing the device. Close the program or file probably fix the problem.

In case we do not have open a document or file, we must try to close programs that have accessed the device, even if the software no longer access the files.

How unlock files

To cite an example, in the case that we have been working with a .doc document from an external storage unit, in addition to close and save the job, it is also a good idea to close Word and the instance of Windows Explorer with which we have access to files.

In the event that the above tricks do not work, we can always fall back button off the system and disconnect the USB cable from the device, which will always work, even if you lose a considerable time, especially when it comes to working hours.

In the event that this situation is repeated many times

It is also possible some scenarios the situation is repeated several times in the day, and interrupt our work with the resulting lack of productivity.

For these cases, nothing better than a small application called IOBit Unlocker, a free utility available for Windows 32 or 64 bits that allows us to release files and storage units with just one click.

How unlock files

To unlock storage units with this software, we move to the window “This PC”, select the removable drive we want to unlock and with the right mouse button select “IObit Unlocker” from the menu.

How unlock files

At this point a window with all the files and programs that are accessing the drive at that time will be presented.

To unlock the files, all you have to do is select the file or storage unit blocked and then clicking the “Unlock” button.

How unlock files

If you wish, you can download Unlocker from this link.

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