Decoding the labeling of SD and MicroSD memory cards. Everything you wanted to know about SD memory cards, but were afraid to ask SD card speed

Many users who do not have much experience with portable gadgets are wondering what MicroSD is.

MicroSD is one of the subtypes of SD cards (Secure Digital Memory Card). This card is a storage medium intended for use in portable equipment. For example, devices such as and video cameras are most often equipped with a slot for connecting SD or MicroSD cards.

The SD card format was developed based on the old MMC card format back in 1999 by Panasonic, SanDisk and Toshiba. The SD Card Association was later founded to organize efforts to improve and promote the SD format. However, MicroSD cards appeared only in 2004, when SanDisk introduced the TransFlash standard. And already in 2005, the TransFlash standard was officially approved by the SD Card Association under the name MicroSD.

MicroSD cards have ultra-compact dimensions (20×21.5×1.4 mm and weight 1 gram), allow you to store up to 32 gigabytes of data, and at the same time provide high operating speed. A device with similar characteristics was simply doomed to enormous popularity.

Область применения SD и MicroSD

SD карты бывают трех типов: обычные SD карты, MiniSD и MicroSD карты

Ordinary SD cards are most often used in photos and cameras for storing footage. В то время как MiniSD и MicroSD используются в более компактных устройствах. Thus, most modern mobile phones, smartphones and communicators are equipped with a slot for connecting a MicroSD card. В этом случае MicroSD карта используется , видеороликов, музыки и программ.

In addition to being used in mobile technology, SD cards are increasingly used as a storage medium for larger equipment. For example, a large number of modern

The amount of information required for work and entertainment is increasing every day. The quality of photographs and video files increases, and along with it their “weight” also increases. As a result, the built-in memory of our gadgets, especially those from the budget segment, is sorely lacking. This problem can be easily solved, especially in phones with a removable battery. Why in them, how to choose a memory card for a phone for any budget and many other questions will be discussed in this article.

Memory card. What is this?

Typically, the memory card is a small black rectangle, but sometimes the appearance is different. Depending on the model, it has a different amount of memory. Modern models of various gadgets use only one type of memory card - microSD, although there are quite a large number of them.

Previously, when mobile phones were just beginning to acquire additional memory, each manufacturer tried to invent its own format, different from the others. For example, the memory card of an LG phone could not be installed in a Nokia. Over time, this trend, as well as specific charging connectors, gradually faded away. This has its own advantage, because after changing your smartphone, you now don’t have to re-purchase this important accessory for it.

How much volume do I need?

When it comes to the required capacity of an SD Card, you should first ask yourself what files you work with most often. In order to get your bearings at least a little, you can take a look at the following list, showing the approximate size of the files we are used to:

• Melody or track - from 3 to 10 megabytes.
• Photo - from 1 to 5 megabytes.
• Film (depending on quality) from 700 megabytes to several gigabytes.

If you are used to using only high-quality content, then you will have to think about memory cards of 32 GB or more. If the card is needed only to store a small playlist and current photos, its volume can be easily calculated using the above information. We can definitely say that with large volumes of photos, there will not be enough internal space, and a memory card is required. A phone with 2 GB of memory is simply not capable of storing the number of videos and photos that modern youth are accustomed to taking.

Feature regarding the capacity of the new memory card

Probably everyone who has previously encountered memory cards or flash drives has noticed that there is a little less space on them than stated by the manufacturer. Why does this problem occur and can it be fixed?

In reality there is no problem. The reason lies in the principles of computing space by a computer or telephone. We are accustomed to multiplying all quantities by a thousand, as, for example, there are a thousand grams in one kilogram. However, in the computer world, calculations are done a little differently, and a number of 1024 is considered to be one. As a result, such an error arises on the missing 24 bytes for every thousand. Therefore, manufacturers should not be blamed for such a “shortage”, and an SD memory card with “cut down” memory is actually quite normal.

What is a memory card class

All memory cards are divided not only by capacity, but also by class. Therefore, when you decide how to choose a memory card for your phone, do not forget about this parameter. The class displays the speed at which any information is written to it. There are cards of various classes, but the most popular in our stores are 4, 10 and U1.

In fact, everything is clear with digital classes - a four is equal to a write speed of up to 4 MB/s, and a ten is equal to up to 10 MB/s, respectively. With the U1 class it is a little more interesting, since manufacturers promise speeds not up to, but from 10 MB/s, but what the maximum possible will be, you have to check on the spot. This class is considered a newer standard, and the SD memory card marked with it differs better from its predecessors.

In addition to the above, there are also digital classes SD Card 2 and 6, as well as the new generation class U3. Digital are no different from their predecessors, that is, they correspond in the same way to the maximum recording speed. Class U3 is currently considered the highest and allows you to write information at speeds of over 30 MB/s. But, despite the high level of development of smartphones, none of them need such a high speed yet, so we will not consider it in detail.

Which one do I need?

Let's look at what each class of memory card can be used for. This will be another step towards how to choose a memory card for your phone and not make a mistake.

• Class 2 memory cards are designed for data storage and are the slowest and cheapest option. You can record music and video files on them, but the recording process itself will be quite lengthy. Problems may occur when viewing high-definition videos.
• Class 4 memory cards are the most popular and common. Fully meet the speed needs of budget phones and smartphones related to multimedia files. Still, it’s better not to use it for games and programs.
• Class 6 memory cards can already be a replacement for the internal memory of some electronic devices and are designed for recording and storing any type of files.
• Class 10 memory cards are the fastest type of cards, the maximum capabilities of which can be used by any smartphone. Allows you to record video in high resolution and perform other tasks that require high-speed recording of information.
• U1 class memory cards are an improved class 10, with a slightly higher write speed and significantly faster reading, as a result of which they can be used for program files, since loading from them will be much faster.
• U3 class memory cards are used very rarely, since their characteristics are only needed when recording video in 4K resolution, and the cost is very high.

What is the maximum memory card capacity supported by the device?

Often, most manufacturers themselves indicate in the characteristics of a phone or smartphone what size memory card is recommended to be installed in the gadget. However, sometimes this information is not indicated directly, but using the coding of different types of cards. It's worth taking a look at the device specification and seeing which cards are supported. The following may be written there:

• microSD cards are an old standard that requires the installation of a phone micro memory card with a capacity of no more than 4 GB. Sometimes some Chinese manufacturers write that cards up to 8 GB are supported with the same marking, but no more.
• microSDHC cards are the most common format among budget phones and smartphones today. Provides the ability to expand memory with cards up to 32 GB, which is quite enough for most users.
• microSDXC cards are a new format that allows you to work with volumes up to 2 TB. Often, cards of this size can be very expensive, but a very popular, inexpensive, and functional solution would be to install additional memory of 64 or 128 GB.

How to decide on the manufacturer

In fact, there is not much difference between memory cards from different manufacturers. They are all quite reliable, so the final weighty argument when choosing can only be the price or attractive appearance. The speed of the card, as discussed above, depends only on its class.

Sometimes on older devices there is a situation where memory cards of the maximum capacity for the gadget do not work from all manufacturers. Even the developers of this or that gadget cannot answer what this is connected with. For example, a similar question was previously discussed on forums - I bought a regular memory card, I didn’t see it at close range, although it worked with other devices without problems. Therefore, when buying a memory card, it is best to take with you the device for which it is intended. This way you can avoid unnecessary stress associated with returning an incorrect accessory.

Instructions for installing a memory card

How exactly and where to place the card itself is often written in the user instructions for the device. However, another important point is often missed. Some devices can easily read data written to a card with a file system of one of the common formats. But after prolonged use, failures may occur, which can lead to the loss of important information.

To prevent this from happening, it is recommended that immediately after installation, while there is no data on the card, you format it directly using your phone or smartphone. Don’t be lazy to do this operation, because later it can protect you from unnecessary worries. This concludes the recommendations on how to choose a memory card for your phone. We hope you will not have any problems purchasing this accessory.

Let's try to find out what class of memory card you should equip your smartphone, tablet, laptop, video camera or camera when such a need arises, and which class of memory card is better for each of these devices?

To do this, we will consider in detail what classification of memory cards currently exists, and how one miniature storage device differs from another.

Before you find out what a storage device class means, you should clarify the concept of storage media speed. There are two different values ​​for this parameter: the first is the speed of reading or transferring data, and the second is the speed of writing data. The read speed is almost always faster than the write speed, but it has no direct relation to the class of equipment: it may even turn out that a flash drive labeled “class 4” will be read faster than a class 10 flash drive.

Of the two numbers describing the characteristics of the media, this will be the larger number: the higher the reading speed, the easier and faster you can transfer information to an external device. Recording speed is important to hardware performance and is what allows you to record high-definition video. You can find out whether the manufacturer offers a good speed recording mode by looking at the back of the package.

Since some unscrupulous manufacturers indicate inflated specifications on their products, it is better to purchase memory cards from well-known brands, but, in any case, it is always possible to check the speed data yourself. It is easy to check the speed using special programs, for example, USB-Flash-Banchmark and Check Flash, which can be downloaded for free, or the H2testw utility.

Existing types of cards

Modern digital storage media comes in different sizes: mini, micro and full-format, with the smallest sizes intended for a smartphone, tablet or mobile phone, and the larger ones used in camcorders and cameras.

For a long time, the main storage medium was CompactFlash, or CF cards, measuring 43 x 36 x 3.3 mm, and although the age of these formats has passed, they are nevertheless still used in some DVRs today.

The most common type of digital storage equipment currently is the SD Card (Secure Digital Memory Card) or SD card.

This device, no larger than a postage stamp, with dimensions of 32 x 24 x 2.1 mm, surpassed CF cards in all respects, and almost all modern equipment is compatible with it. Higher-capacity devices are now abbreviated SDHC, and ultra-high-capacity devices are abbreviated SDXC.

Micro SD or micro SD card is simply a miniature version of an SD card, measuring 11 x 15 x 1 mm, which is inserted into devices with limited space, such as phones. However, if necessary, it can even be installed in a laptop if you use a special adapter that exists for this purpose. There is also a mini SD with dimensions of 21.5 x 20 x 1.4 mm, since some types of equipment are equipped with just such slots.

SD classes of memory cards

Let's assume that we already know what size the storage device should be, how much of its memory we need for optimal operation. All that remains is to find out what a memory card class is and what this SD card parameter affects in order to select the one you need. It is this characteristic that will determine the speed at which we can transmit or receive the information we are interested in.

So, this is a parameter that determines the speed of the SD memory card, according to which all devices are divided into:

1. Class 2 - speed from 2 Mb/s to 4 Mb/s. Since the writing speed is very low, this class of flash drive should not be used in video cameras or digital cameras. The lack of speed is compensated by the relative cheapness of the card, so it can be safely used to reproduce sound and images, that is, in audio or video players, since in this case high speed is not needed.
2. Class 4 - speed from 4 Mb/s and higher. For amateur home photography with digital cameras, you can use class four. The fourth class, in addition, is installed in the DVR and some inexpensive non-professional video cameras.
3. Class 6 - guaranteed speed of 6 Mb/s and higher. A flash drive of this level can already be installed in semi-professional video cameras and SLR cameras that shoot in RAW format. They allow you to get fairly high quality shooting.
4. Class 10 - speed is 10 Mb/s and higher. A Class 10 flash drive can be equipped with a car recorder, professional video and photo equipment with Full HD recording. Class 10 allows you to take burst photos, shoot in RAW format and save images, which is of great importance for professional photographers. However, such devices are somewhat more expensive, for example, a microsdhc class 10 memory card will cost at least 1000 rubles.
5. SD Class 16 - speed of at least 16 Mb/s, however, it is still very difficult to buy this card in our country, since it has not yet been widely sold.
6. Ultra High Speed ​​(UHS) - such ultra-high speed cards can only be used with devices compatible with them, which is usually written about in the instructions. Class 10 UHS I is a high-speed card, the writing speed of which can reach 50 MB/s or more.

There is a UHS specification that regulates the speed of equipment. According to the UHS-I standard, the data exchange speed must be at least 50 Mb/s and up to 104 Mb/s, according to the UHS-II standard - at least 156 Mb/s and up to 312 Mb/s. The class 10 uhs i card allows you to provide the highest level of real-time recording and, in addition, get large-size video in HD format.

How to determine the class of a memory card? You just need to look at it carefully: the circled number on the front of the digital storage medium will be the desired value.

How to choose a flash drive

Please note that the latest memory device formats may not work with older hardware. For example, if a smartphone supports the micro SD format, this does not mean that it will also support high-speed micro SDXC. Therefore, to find out this possibility, it is better to read the documentation for your smartphone in advance.

Micro SD, like SD media, comes in two formats (SDHC with a capacity of up to 32 GB and SDXC with a capacity of 64 to 512 GB) and are used in all modern smartphones and tablets. The tenth speed class of such information media is no different from their full-size counterparts. Thus, the higher the classes of sdhc memory cards, the faster data transfer occurs, which is the main advantage of those micro SD cards that cost more for the same capacity.

For example, a microsdhc class 10 32GB memory card costs about 1,500 rubles. Ideal for modern digital devices such as phones, camcorders, smartphones, PDAs, audio players and game consoles. If you don’t skimp on the class of equipment, pursuing immediate benefits, you can get long-term excellent results in the further use of the equipment: high-quality pictures and stunning videos, as well as funds from their sale.

If your phone or tablet running Android 6.0, 7 Nougat, 8.0 Oreo or 9.0 Pie has a memory card slot, then you can use a MicroSD memory card as the internal memory of your device, this feature first appeared in Android 6.0 Marshmallow.

On the latest version of Android, all the steps to convert a MicroSD memory card into an internal one are almost the same, but just in case, I will describe the steps separately and provide screenshots (do not forget that all data from the memory card will be deleted in the process, take care of saving important files) :

This will complete the procedure. All operating features and the method of returning the memory card to operation as a portable storage device remain the same as for previous versions of Android.

Video instruction

Features of the memory card working as internal Android memory

It can be assumed that when a memory card size M is added to Android's internal memory of N, the total available internal memory should become N+M. Moreover, approximately this is also displayed in the information about the device’s storage, but in fact everything works somewhat differently:

As a result, after the moment when the SD memory card began to be used as internal memory, the user does not have access to the “real” internal memory, and if we assume that the device’s own internal memory was larger than MicroSD memory, then the amount of available internal memory after of the described actions will not increase, but decrease.

Formatting a memory card for use as internal storage in ADB

For Android devices where the function is not available, for example, on Samsung Galaxy S7-S9, Galaxy Note, it is possible to format the SD card as internal memory using ADB Shell.

Since this method can potentially lead to problems with the phone (and may not work on every device), I will skip the details on installing ADB, enabling USB debugging and running the command line in the adb folder (If you don’t know how to do this, then , perhaps it’s better not to take it. And if you take it, it’s at your own peril and risk).

The necessary commands themselves will look like this (the memory card must be connected):

1. adb shell
2. sm list-disks(as a result of executing this command, pay attention to the issued disk identifier of the form disk:NNN,NN - it will be needed in the next command)
3. sm partition disk:NNN,NN private

When formatting is complete, exit the adb shell, and on your phone, in the storage options, open the “SD card” item, click on the menu button at the top right and click “Transfer data” (this is required, otherwise the phone’s internal memory will continue to be used). Once the transfer is complete, the process can be considered complete.

Another option for such devices, if you have root access, is to use the Root Essentials application and enable Adoptable Storage in this application (a potentially dangerous operation, do not perform at your own risk on older versions of Android).

How to return the usual functioning of a memory card

If you decide to disconnect the memory card from the internal memory, this is easy to do - transfer all important data from it to the computer, then go to the SD card settings, just like in the first method.

Then, in the memory card actions menu, select “Portable media” and follow the instructions to format the memory card.

Almost all GPS/GLONASS car navigators are equipped with an SD memory card reader designed for storing navigation software, map data and various multimedia information. Moreover, every user of modern digital technology has at least once been faced with the need to choose or purchase memory cards popular foriat SD, microSD, miniSD or their more "capacious brothers" - SDHC, microSDHC or miniSDHC. Everyone knows the names of these memory cards, and most of us are sure that microSD and microSDHC are synonymous words, meaning memory cards with absolutely the same characteristics. However, this is not quite true...

Physical sizes of memory cards SD, SDHC

SDHC memory cards are available in three overall formats:

• SD, SDHC - size (w*in*g): 32*24*2.1 mm;
• minisd, mini sdhc - size (w*in*g): 21.5*20.0*1.4 mm;
• Microsd, microSDHC - size (w*in*g): 11*15*1.0 mm.

Rice. 1 - Comparison of the sizes of various overall dimensions of SD -cards of memory

Currently, memory cards of large formats microSD and SD are most widely used as storage media for GPS car navigators. Most manufactured SD memory cards are in the dimensional microSD format, and an adapter to the SD format is included with it, with which a microSD memory card can be inserted into any slot for a regular SD card.

Rice. 2-the equal dimensions of the adapter (adapter), microSD cards and a 5-ruble coin

History of the appearance of SD, SDHC formats

Standard SD (Secure Digital Memory Card) was developed in August 1999 by Panasonic, Sandisk and Toshiba based on MMC memory card And in 2000, Matsushita, Sandisk and Toshiba were announced by the creation of SD Card Association.

All SD memory cards are equipped with their own controller and array of memory cells. Unlike MMC memory cards, the algorithm for writing to an SD memory card is designed in such a way that “illegal” reading of information is impossible, which is what was enshrined in the name - “Secure Digital”. The card can be protected with a password, without which it becomes practically inoperable. If the password is lost, then the only way to “restore the functionality” of the card is by reformatting it. Naturally, all data will be irretrievably lost. The SD card is also equipped with a mechanical write-protect switch. In the “lock” position, recording information, deleting files, and formatting the card are impossible. This is another way to prevent accidental loss of information. It should be taken into account that this type of protection (mechanical switch) is assigned to the device working with the card and may not be implemented. In most cases, SD can be replaced with an MMC card. Replacing in the opposite direction is usually not possible, since the SD is thicker and may simply not fit into the MMC slot.

So the standard SD is a further development of the standard MMC. In terms of size and characteristics, SD cards are very similar to MMC, only slightly thicker. The main difference from MMC is the copyright protection technology: the card has cryptographic protection against unauthorized copying, increased protection of information from accidental erasure or destruction, and a mechanical write-protect switch. The maximum capacity of SD memory cards is 4 GB.

Format SDHC (Secure Digital High Capacity) is a further development of the popular SD format (originally known as TransFlash, T-Flash), inheriting most of its characteristics. Potential maximum capacity of SDHC cards increased to 32 GB(for SD cards the maximum capacity is 4 GB). As a rule, the FAT32 file system is used to store information on SDHC cards (FAT16/32 was used for SD).

So what are the differences between SD and SDHC memory cards?

The key innovation for SDHC cards, which allowed them to exceed the capacity of 4GB, was introduction of sector-by-sector addressing(similar to hard drives), while regular SD cards have byte addressing (like RAM) and, accordingly, with a 32-bit address they can have a capacity of no more than 4GB. Thus, SD and SDHC memory cards require completely different principles for accessing their memory cells. SDHC memory cards are not compatible with devices that are natively designed only for SD cards, but devices that are capable of working with SDHC cards also support SD cards.

Data transfer speed of SD and SDHC cards

Association of Card Manufacturers - SDCard Association for the purpose of unification, introduced a classification of speed characteristics of SDHC cards and devices for working with them, the so-called SD Speed ​​Class :

• SD Class 2 - recording speed of at least 2 MB/s;
• SD Class 4 - recording speed of at least 4 MB/s;
• SD Class 6 - recording speed of at least 6 MB/s;
• SD Class 10 - write speed of at least 10 MB/s.

The recording speed in accordance with this classification is indicated in the technical specifications of the memory card, for example recording: MicroSDHC memory card (Class 4) - means that this memory card is in microSDHC format and allows you to write data to it with a guaranteed minimum speed of 4 MB/s .

The reading speed of SD and SDHC memory cards is usually 2...4 times higher than the writing speed and is often not indicated in the specifications for the memory card.

Be careful when choosing SD memory cards and check with the seller and manufacturer about the type of memory cards supported by your car navigator!

Based on Wikipedia materials - http://ru.wikipedia.org