Micro SD Memory Cards: Difference between microSDHC, microSDXC and microSD
Sep 25, · Micro SDHC Also known as Secure Digital High Capacity, it is much as the same as your micro SD cards, but has a higher storage capacity of 4 GB up to 32 GB. It is still a secure digital card that has the same standard size of 11mm by 15mm. It also has a higher transfer rate of potentially 50 MB/s and up to MB/S/10(). Micro SD - A classic Micro SD has a maximum of 2 GB of storage; Micro SD HC - The memory of a mircoSDHC is between 4 and 32 GB; Micro SD XC - The memory of a mircoSDXC is between 32 GB and 3 TB; HC and XC are merely abbreviations for High Capacity and eXtended Capacity and give information about how much memory is available on the microSD.
Info by MemoryMan Last update on Created how to connect wifi adapter Currently I am looking for a new microSD memory card for my smartphone. When starting, it was not easy for me to find my way through this jungle of different terms.
However, by now, I have researched and I would not deprive you of my findings. There is only a difference in the what is microsdhc vs microsd volume:. I was so confused for nothing. Here you should definitely look into the manual before purchasing a memory card. So, if you have an older smartphone or an older digital camera, you have to pay attention to whether the appropriate file system or the storage size are supported by your device at all.
In some devices, newer cards should have been made running by simply formatting them in another file system. But this way must not work in every device. I thank you so much for including those explanations in your answer and for the compatibility warning. I feel very smart at the moment.
I am bookmarking this page for all my needed tech answers…. You get respect that you searched and found the answer. Im an old guy too with memory problems. Now that will be advanced tech!! HC - high capacity XC - eXtended capacity at If you how to take apart a dell inspiron m5010 to know it in detail, see the discussion about why USB sticks what is microsdhc vs microsd showing what is wireless transmission media memory than specified.
The SD card, like a disk drive, has to be formatted for computer system, like little compartments to store your data blocks or files. Each compartment has an address like your mailbox so the computer can find the file again quickly.
Without some for of addressing it would have to start at the beginning and search sequentially to the end every time you access the SD card so they set up a File Address Table FATlike an index for a book, to speed things up and organize your files. This is why the "available" storage is always lower than the maximum shown but the good news it shows your SD card is formatted and working.
That was an outstanding, understandable description of the FAT file system. Can you tell us about the exFAT file system? Explanations that are understandable to those without even some expertise in a matter are rare - and yours was excellent! All right you Folks, I'm a 62 year old blissfully retired old fart. I just bought a just for reading tablet and it has a "TF Card".
Is that just an old SD card? I'm not sure of the max my new tablet can hold and I need to contact the mfg. However, I came along this post and thought you'd all want to throw this into the mix and see what comes out ;0 Also, give the info here, do you think that a SDHC disk will be compatible that is if max size is high enough.
You all ROCK!!! Sincerely, Sharon "Live'n here in Allentown" at The author has not added a profile short description yet. Show Profile. What is microsdhc vs microsd note: The contributions published on askingbox.
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Learn more. Ask your own question or write your own article on askingbox. Reply Positive Negative Date Votes. Much appreciated, MemoryMan. Reply Positive Negative. We have this problem at a quarter of your age. Positive Negative. That is not correct. Hey, do you know that you can retrieve the missing capacity of your SD?
For example, you bought a 64 GB SD, and when you read it, it only shows No need to worry about that. This is just because of a different kind of counting the bytes. Hello Everyone! About the Author The author has not added a profile short description yet. Question what is microsdhc vs microsd Answer. How to free my phone memory Question 3 Answers. Participate Login Register Ask Question. Info User Top Donate Advertise here. About About us Contact Imprint.
Class 2, 4, 6 and 10 Memory Cards
We all use SD cards, be it a one used in cameras or a micro SD card used in mobile phones. An SD Card (Secure Digital Card) is an ultra small flash memory card designed to provide high-capacity memory in a small size.(Source: Webopedia) SD Card-Secure Digital Card SDHC Card-Secure Digital High Capacity Card SDXC Card-Secure Digital eXtended Capacity Card. An SD card measures 32 by 24 by mm, while the microSD card is 15 by 11 by 1 mm. A microSD card is much smaller than a standard SD card. Dave Johnson/Business Insider.
The SDA uses several trademarked logos owned and licensed by SD-3C to enforce compliance with its specifications and assure users of compatibility. Developers predicted that DRM would induce wide use by music suppliers concerned about piracy. For this reason the D within the logo resembles an optical disc. The SD Association, headquartered in San Ramon, California, United States, started with about 30 companies and today consists of about 1, product manufacturers that make interoperable memory cards and devices.
Early samples of the SD Card became available in the first quarter of , with production quantities of 32 and 64 MB  cards available three months later. While the new cards were designed especially for mobile phones, they are usually packaged with a miniSD adapter that provides compatibility with a standard SD memory card slot.
TransFlash and microSD cards are functionally identical allowing either to operate in devices made for the other. The card was originally called T-Flash,  but just before product launch, T-Mobile sent a cease-and-desist letter to SanDisk claiming that T-Mobile owned the trademark on T- anything , [ citation needed ] and the name was changed to TransFlash. Initially, microSD cards were available in capacities of 32, 64, and MB. Since , miniSD cards are no longer produced, due to market domination of the even smaller microSD cards.
The storage density of memory cards has increased significantly throughout the s decade, allowing the earliest devices to offer support for the SD:XC standard, such as the Samsung Galaxy S III and Samsung Galaxy Note II mobile phones, to expand their available storage to several hundreds of gigabytes. In April , Panasonic introduced MicroP2 card format for professional video applications.
Secure Digital includes five card families available in three different sizes. Electrically passive adapters allow a smaller card to fit and function in a device built for a larger card. The SD card's small footprint is an ideal storage medium for smaller, thinner and more portable electronic devices. Secure Digital changed the MMC design in several ways:.
Full-size SD cards do not fit into the slimmer MMC slots, and other issues also affect the ability to use one format in a host device designed for the other. Version 2. Version 3. Version 4.
Version 5. However, SD cards can be reformatted to any file system required. Therefore, even if a file system is supported in general, it is not always possible to use alternative file systems on SDXC cards at all depending on how strictly the SDXC card specification has been implemented in the host device.
This bears a risk of accidental loss of data, as a host device may treat a card with an unrecognized file system as blank or damaged and reformat the card. SD card speed is customarily rated by its sequential read or write speed. The sequential performance aspect is the most relevant for storing and retrieving large files relative to block sizes internal to the flash memory , such as images and multimedia. Small data such as file names, sizes and timestamps falls under the much lower speed limit of random access , which can be the limiting factor in some use cases.
This was superseded by the Speed Class Rating , which guarantees a minimum rate at which data can be written to the card. The newer families of SD card improve card speed by increasing the bus rate the frequency of the clock signal that strobes information into and out of the card. Whatever the bus rate, the card can signal to the host that it is "busy" until a read or a write operation is complete.
Compliance with a higher speed rating is a guarantee that the card limits its use of the "busy" indication. Specified in SD version 3. Specified in version 4. Version 6.
Both are full-duplex. Use of UHS-I requires that the host device command the card to drop from 3. The higher speed rates are achieved by using a two-lane low voltage 0. In full-duplex mode, one lane is used for Transmit while the other is used for Receive.
In half-duplex mode both lanes are used for the same direction of data transfer allowing a double data rate at the same clock speed. Supporting cards must also implement the NVM Express storage access protocol.
The Express bus re-uses the pin layout of UHS-II cards and reserves the space for additional two pins that may be introduced in the future. Hosts which implement version 7.
Version 8. The SDA also released visual marks to denote microSD Express memory cards to make matching the card and device easier for optimal device performance.
Both read and write speeds must exceed the specified value. The specification defines these classes in terms of performance curves that translate into the following minimum read-write performance levels on an empty card and suitability for different applications:    .
Speed Class ratings 2, 4, and 6 assert that the card supports the respective number of megabytes per second as a minimum sustained write speed for a card in a fragmented state. The combination lets the user record HD resolution videos with tapeless camcorders while performing other functions. It is also suitable for real-time broadcasts and capturing large HD videos.
Class A1 requires a minimum of reading and writing operations per second, while class A2 requires and IOPS. If used in an unsupported host, they might even be slower than other A1 cards. The 2. Manufacturers may report best-case speeds and may report the card's fastest read speed, which is typically faster than the write speed.
Some vendors, including Transcend and Kingston , report their cards' write speed. In applications that require sustained write throughput, such as video recording, the device might not perform satisfactorily if the SD card's class rating falls below a particular speed. For example, a high-definition camcorder may require a card of not less than Class 6, suffering dropouts or corrupted video if a slower card is used.
Digital cameras with slow cards may take a noticeable time after taking a photograph before being ready for the next, while the camera writes the first picture.
The speed class rating does not totally characterize card performance. Different cards of the same class may vary considerably while meeting class specifications.
A card's speed depends on many factors, including:. In addition, speed may vary markedly between writing a large amount of data to a single file sequential access , as when a digital camera records large photographs or videos and writing a large number of small files a random-access use common in smartphones.
A study in found that, in this random-access use, some Class 2 cards achieved a write speed of 1. Cards can protect their contents from erasure or modification, prevent access by non-authorized users, and protect copyrighted content using digital rights management. The host device can command the SD card to become read-only to reject subsequent commands to write information to it.
There are both reversible and irreversible host commands that achieve this. Most full-size SD cards have a "mechanical write protect switch" allowing the user to advise the host computer that the user wants the device to be treated as read-only.
This does not protect the data on the card if the host is compromised: "It is the responsibility of the host to protect the card. The position of the write protect switch is unknown to the internal circuitry of the card.
The switch is a sliding tab that covers a notch in the card. The miniSD and microSD formats do not directly support a write protection notch, but they can be inserted into full-size adapters which do.
When looking at the SD card from the top, the right side the side with the beveled corner must be notched. On the left side, there may be a write-protection notch. If the notch is omitted, the card can be read and written.
If the card is notched, it is read-only. The diagram to the right shows an orange sliding write-protect tab in both the unlocked and locked positions. Cards sold with content that must not be altered are permanently marked read-only by having a notch and no sliding tab.
A host device can lock an SD card using a password of up to 16 bytes, typically supplied by the user. A locked card interacts normally with the host device except that it rejects commands to read and write data. A locked card can be unlocked only by providing the same password. The host device can, after supplying the old password, specify a new password or disable locking. Without the password typically, in the case that the user forgets the password , the host device can command the card to erase all the data on the card for future re-use except card data under DRM , but there is no way to gain access to the existing data.
Windows Phone 7 devices use SD cards designed for access only by the phone manufacturer or mobile provider. An SD card inserted into the phone underneath the battery compartment becomes locked "to the phone with an automatically generated key" so that "the SD card cannot be read by another phone, device, or PC". It is therefore possible to use a device such as the Nokia N8 to reformat the card for subsequent use in other devices.
Some of the earliest versions of microSD memory cards with secure elements were developed in by DeviceFidelity, Inc. Various implementations of smartSD cards have been done for payment applications and secured authentication. MicroSD cards with Secure Elements and NFC near field communication support are used for mobile payments, and have been used in direct-to-consumer mobile wallets and mobile banking solutions, some of which were launched by major banks around the world, including Bank of America , US Bank , and Wells Fargo ,    while others were part of innovative new direct-to-consumer neobank programs such as moneto , first launched in Vendors have sought to differentiate their products in the market through various vendor-specific features:.
SDIO cards are only fully functional in host devices designed to support their input-output functions typically PDAs like the Palm Treo , but occasionally laptops or mobile phones. Inserting an SDIO card into any SD slot causes no physical damage nor disruption to the host device, but users may be frustrated that the SDIO card does not function fully when inserted into a seemingly compatible slot. USB and Bluetooth devices exhibit comparable compatibility issues, although to a lesser extent thanks to standardized USB device classes and Bluetooth profiles.
Two other unique features of Low-Speed SDIO are a maximum clock rate of kHz for all communications, and the use of Pin 8 as "interrupt" to try to initiate dialogue with the host device. The one-bit SD protocol was derived from the MMC protocol, which envisioned the ability to put up to three cards on a bus of common signal lines. The cards use open collector interfaces, where a card may pull a line to the low voltage level; the line is at the high voltage level because of a pull-up resistor if no card pulls it low.
Though the cards shared clock and signal lines, each card had its own chip select line to sense that the host device had selected it. The SD protocol envisioned the ability to gang 30 cards together without separate chip select lines.
The host device would broadcast commands to all cards and identify the card to respond to the command using its unique serial number. In practice, cards are rarely ganged together because open-collector operation has problems at high speeds and increases power consumption.
Newer versions of the SD specification recommend separate lines to each card.
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