Types and characteristics of USB and flash drives. Types of flash cards
Every person who constantly works on a computer urgently needs to have such an irreplaceable thing as a USB drive. This can be either a simple flash memory card or a larger multi-gigabyte drive that is needed to transfer information. Today we’ll try to decide which is the best USB flash card to choose for solving various problems.
That, which flash drive to choose, depends on the amount of information you are transferring. In fact, our drive has a lot of functions. First of all, it's volume. If you need to transfer small information, it is not necessary to buy a small flash drive. At the same time, the difference in price for 2 gigabytes, 4 gigabytes and 8 gigabytes will not be large. By choosing an 8 GB storage medium, you will benefit in both price and quality. Today, many drives write at good speed. The download speed is ten megabits/s, but they read on average in fifteen megabits/s.
Types and classes of flash memory cards
Of course, there are also very fast flash drives. That is, you need to pay attention to the specific model of the flash drive you are buying. If you find the words “ultra fast” or “hi-speed” on it, then this is a wonderful model with high writing and reading speeds. In general, all flash drives are divided into types and classes.
SD (Secure Digital) is a portable flat-plate memory card standard designed for use in portable devices - cameras, camcorders, etc. Classified into the following classes:
- SD 1.0 - from 8 MB to 2 GB
- SD 1.1 - up to 4 GB
- SD Class 2 - write speed of at least 2 MB/s - 13x
- SD Class 4 - write speed of at least 4 MB/s - 26x
- SD Class 6 - write speed of at least 6 MB/s - 40x
- SD Class 10 - write speed of at least 10 MB/s - 66x
Since this storage format is very popular, an SD card, thanks to various adapters, can be used with almost any device, be it a computer, laptop or even a tablet - via a card reader or directly via USB.
miniSD and microSD (TransFlash) are types of SD cards that can be used to connect to an SD slot using a special adapter. Mini is also often used in cameras, while Micro is often used in smaller devices such as phones, tablets, and video recorders.
SDHC (Secure Digital High Capacity) is another more modern type of SD, characterized by greater speed. Outwardly, they do not differ from SD, but they can only work with those devices that specifically indicate card support of this type. Sometimes it happens that the device becomes able to work with SDHC after a firmware update. Such cards are available in capacities from 4 to 32 GB.
SDXC (Secure Digital eXtended Capacity) are SD flash cards with extended capacity.
SD 3.0 - cards with a capacity of 64GB and maximum speed up to 90 Mbps, which may be compatible with some existing SDHC devices
SD 4.0 speed is up to 300MB/sec, and the card capacity can be from 64GB to 2TB. They are not fully compatible with SDHC devices.
Which USB flash drive to choose?
Quality and reliability depend in direct proportion not only on the class, but also on the manufacturer you choose. Samsung, Transcend, SanDisk and Kingston are considered famous flash drives for their quality products. And besides, you can find good quality flash drives from companies such as PQI, Lexar, Pretec and Imation.
It also happens that brands that no one knows use other people’s devices in the production of cases with their logo. You shouldn’t refuse them either, since with the same components they are much cheaper, that is, you won’t overpay for the brand.
It is worth noting that the external size of a USB drive does not affect its actual capacity. You can also find very small flash drives that are similar in size to SIM cards. Here it’s a matter of each person’s taste - a small drive or a large one, but in terms of price, small cards are more expensive and it’s also easier to lose them.
I hope the described points will help you choose a USB flash drive that will facilitate the fastest and most secure work on your computer. When choosing, we choose popular manufacturers, but do not forget about little-known companies with components from famous companies- it's cheaper with the same quality.
Well, for a snack today - a video about how to find out the real size of your flash drive. Bye!
Today's article is a short educational program on SD memory cards. These flash cards are widely used in modern technology: V mobile phones, GPS navigators, cameras and video cameras.
SD is by far the most popular memory card standard today. The vast majority of devices that work with memory cards support this standard.
SD memory cards come in three different sizes. This made it possible to cover different devices: from miniature audio players to professional video cameras.
So, what are there? SD memory card form factors :
microSD– these cards are intended for use in mobile phones, smartphones, tablets and other compact devices.
– these cards have a little larger size than microSD. Until recently, they were used in mp3 players and other portable equipment. But today they have lost their popularity and are used less and less.
SD– cards largest size. They are used in cameras, video cameras, video recorders and other relatively large portable equipment. New generation cards SDHC And SDXC are exactly the same size as SD.
By the way, you can insert a card of a smaller form factor into a device designed to work with large SD cards. To do this you need to use a special adapter:
But it’s better not to do this unless absolutely necessary, because... Usually microSD cards are much slower than full-fledged SD cards.
Exists four generations of SD memory cards :
- SD 1.0– holds information volume from 8 MB to 2 GB
- SD 1.1– up to 4 GB
- SDHC– up to 32 GB
- SDXC– up to 2 TB
In the case of SD cards, there is backward compatibility: i.e. devices capable of working with SDXC understand the SDHC format and the older SD format (but not vice versa!).
Memory cards differ not only in size or capacity. One of the main parameters is speed exchange information with the device.
SD memory card speed manufacturers designate either as class, or in the form multiplier:
- SD Class 2– recording speed not less than 2 MB/ With 13x;
- SD Class 4– recording speed not less than 4 MB/s, which corresponds to the multiplier 26x;
- SD Class 6– recording speed not less than 6 MB/s, which corresponds to the multiplier 40x;
- SD Class 10– recording speed not less than 10 MB/s, which corresponds to the multiplier 66x;
- SD Class 16– recording speed not less than 16 MB/s, which corresponds to the multiplier 106x.
As you can see, the speed class of a card directly indicates its speed in MB/s. To find out what class your memory card has, just look at its front part: it should be indicated there. For example, in in this case at the card tenth speed class:
Before purchasing an SD memory card, you need to find out what speed class your device requires. This information should be indicated in the instructions for it.
The speed class is important for those who are going to shoot video. For example, recording Full HD video requires a write speed of 3 MB/sec, which corresponds to a Class 4 memory card. Using a slower card will cause problems when shooting. However, in some cases, the video bitrate can reach 6 MB/s. Therefore, for video shooting it is better to buy memory cards starting from Class 6 and higher.
How transfer information directly from the SD card to the computer? For this purpose there are special devices called card readers. The card reader can be either external (connected via a USB connector) or built into a computer or laptop.
After connecting the card reader to the computer, insert your memory card into the corresponding slot. After that, go to Windows “Computer” - the flash drive will appear in the “Devices with removable storage” section. You can open it and perform operations with files.
built-in internal card reader
In conclusion, I want to say that when buying an SD card, it is better not to chase the cheapness, but to buy a card famous manufacturer(I would recommend Transcend). Because It will be very disappointing to lose captured photos or videos due to a faulty card.
The memory of any phone, computer or camera is not unlimited, so in order to use your device more efficiently, it makes sense to purchase a portable storage medium such as a flash card. In addition, its convenience lies in the fact that you can view files anywhere, even if your gadget is not nearby. Over time, memory cards were modified and underwent a number of changes. On at the moment For certain type devices have their own model of flash drive.
What is a flash card
A few years ago, flash drives were not so widespread in everyday life outside offices and serious institutions. Over the years, the popularity of flash drives has increased significantly, and the average user can no longer imagine their activities without them. A flash drive is a miniature box with hidden microcircuits and a certain type of connector.
The purpose of a flash drive is to accumulate information inside itself and provide the ability to access it at any time via USB or using a special adapter. You can store documents of any format, photos, music and videos on a memory card. How much will fit on a flash drive depends on its volume: it can be so small that it will allow you to record only a few photos in good quality.
Operating principle
Despite its apparent simplicity, the flash drive device is fraught with many secrets unknown to the average user. Inside the compact box there is a complex microcircuit, with the help of which recording, storing and subsequent reading of information is possible. Flash memory is the basis of these devices and is represented by a component such as a floating gate transistor. The methods of connecting memory cards into an array of cells differ, due to which chips of the NOR and NAND types are distinguished. The differences noticeable to the user are in the speed of writing, erasing and reading.
Species
It's not just the intricate design of the memory card that classifies these portable devices. Flash drives have other, more important, parameters that can be used to group them into groups:
- Outer shell. There are flash devices with a USB connector designed to be connected to a computer or other devices that have a suitable input. In addition to them, there are mini- and even micro-memory cards, which are actively used, for example, for photographic equipment or mobile phones.
- Capacity. Capacity plays a role, so it’s better to immediately choose a flash drive with the right number gigabytes, fortunately a wide range will allow you to do this.
- File system. The FAT family is often found in low-capacity flash media. If we're talking about If you talk about larger capacity, then in such cards you will find an NTFS system that has more advanced functions.
Flash drive
The non-volatility of memory cards attracts users who want to save their files and be able to access them at any time. Due to the variety of digital media and information technology In a retail or online store, the average user choosing a flash drive for personal use may simply get lost. Initially, you need to decide on the purpose of purchase and how to use the flash drive.
SD
There are many flash devices on the market with similar names that can make regular user get confused in them. Secure Digital Memory Card is almost the first memory card standard, introduced in 1999. At the moment, such flash devices are still used in certain types equipment and you can buy an SD card in most stores. Distinctive feature Such a card has a small volume: the minimum is 8MB and the maximum is 4GB.
- Name: Transcend TS128MSD100I.
- Price: 650 rubles.
- Characteristics: the card has a capacity of 128MB, has good copying and reading speeds, and has a mechanical write blocker on the side.
- Pros: compatible with most devices, inexpensive.
- Cons: small capacity.
There are more expensive flash drives, where the increase in cost is due to greater capacity or other parameters:
- Name: Apacer Secure Digital Card.
- Price: 1900 rubles.
- Characteristics: flash storage capacity is 2GB, class 10.
- Pros: good speed, medium capacity.
- Cons: none identified.
MicroSD
Miniature devices often also need memory expansion. The MicroSD flash drive is the smallest card currently available. You can find adapters for it on sale, with which the flash drive can be opened, for example, through a laptop. Most card options are similar, but there are options:
- Name: Kingston SDC/2GB.
- Price: 200 rubles.
- Specifications: included microSD card with a capacity of 2GB and an adapter for it.
- Pros: cheap, adapter available.
- Cons: small volume, slow data transfer speed.
Alternatively, at about the same price category you can consider the following option:
- Name: Qumo MicroSD.
- Price: 250 rubles.
- Characteristics: capacity – 4GB, the manufacturer provides a flash drive complete with an adapter.
- Pros: low price, good speed.
- Cons: high percentage defects in batches.
SDHC
Technical progress does not stand still and SD cards gradually began to change. Most of the parameters of these flash drives are inherited from SDHC. However, the huge difference is the significant increase in media capacity. A maximum of 32GB can be written to such a flash drive. Many well-known companies that produced SD cards included SDHC in their lines:
- Name: SanDisk Extreme Pro SDHC UHS Class 1.
- Price: 1000 rubles.
- Characteristics: volume – 8GB, read and write speed – 90-95 MB/s, durable housing.
- Pros: high speed, shockproof card, good value for money.
- Cons: none identified.
Often you can buy a larger flash drive for about the same price. The catch lies in the lower class, which will certainly affect the data transfer speed:
- Name: Kingston SD4.
- Price: 1200 rubles.
- Characteristics: volume – 32GB, class – 4.
- Pros: reliable manufacturer, large volume, reasonable price.
- Cons: average speed.
SDXC
A new standard for compact flash media was developed in 2009. Unlike their brothers, SDXC cards use the exFAT file system. The capacity of flash drives increases to sizes unprecedented at that time, and a small card gains the ability to hold information up to 2TB. Majority modern devices already know how to work with a card of this type.
- Name: Silicon Power Superior Class 10 UHS-I U3.
- Price: 2900 rubles.
- Characteristics: it is possible to record up to 64GB of information, read speed is 90MB/s, write speed is 2 times lower.
- Pros: large capacity.
- Cons: none identified.
For professional photographic equipment, where quality directly affects the weight of the file, it is better to immediately choose a larger card:
- Name: Kingston SDA10.
- Price: 14,000 rubles.
- Characteristics: volume – 512GB, write speed is half the read speed, belongs to class 10.
- Pros: excellent quality of work, proven manufacturer.
- Cons: high price.
How to choose a flash card
In Moscow and St. Petersburg, the choice of flash drives is very wide. If less major cities cannot boast of such an assortment, their residents always have the opportunity to order a memory card via the Internet with delivery by mail. It doesn’t matter whether it’s a flash drive for a phone or a computer, the main thing is to focus on the necessary parameters. Pay attention to the following criteria:
- Volume. It is important that the card fits the amount of information that you plan to record there.
- Format. Among the available types of flash media, you need to choose the one that suits your device.
- Data transfer rate. To ensure that the device to which the flash drive will be connected does not slow down, give preference to memory cards with optimal speed.
- Manufacturer. There are several key leading brands in the flash drive segment - it is better to choose from them.
For phone
When the space on your smartphone begins to quickly run out, the memory needs to be expanded. Not every memory card for a phone may be suitable. It is necessary to understand that since the device is miniature, the flash drive will be similar. The smallest ones are MicroSD, so they will be suitable for phones. There are two options: MicroSDHC and MicroSDXC, which, like their full-size counterparts, differ only in size and supported file system.
If we talk about laptops, then most modern models equipped with built-in adapters for card reading. For those computers that do not have them, you can purchase a separate card reader. By default, all SD flash drives are readable, and for micro cards you will need an adapter. This is very convenient when transferring files from one device to another. For example, in order to free up space on a flash drive from a camera, pictures can be quickly copied to a computer.
Video
Rarely what modern gadget, from camera to phone, does without a removable memory card. Expanding the potential of our digital friend, we strive to buy a card with the maximum capacity. However, the number of gigabytes is not the only one, and often not at all main characteristic external memory. When making a purchase, you should pay attention to the speed class of the memory card. Let's figure out what it is.
SD format and its varieties
Ten years ago, there were many types of memory cards: Compact flash, MMC, xD (Olympus), Memory Stick (Sony) as well as their mini-variants. Today, the SD (Secure Digital) card has become the de facto standard. As a rule, there are slots for this type of card even in products from Sony and Olympus along with their own formats, and CF are found only in some professional cameras.
The first SDs were modified MMCs, to which a small “latch” was added to mechanically protect the card from accidental overwriting of files. However, progress does not stand still. If initially SD memory cards could not be larger than two gigabytes (at that time this seemed fantastic), then with the introduction of the SDHC (High Capacity) standard in 2006, a size of 32 GB became achievable. But even more important was the emergence of SDXC (eXtended Capacity) cards. Not only is their maximum capacity very impressive - 2 terabytes, but the speed also increases greatly - up to 300 MB / sec, which made it possible to introduce new classes of memory cards.
SD memory card sizes
A standard SD card has a size of 32x24 mm. For a camera or video camera, this card size is quite convenient, but for an audio player it is too big. For use in compact devices, a type of miniSD card with dimensions of 21.5x20 mm was developed. The same type was used in the first phones that played music and video.
But phones became smaller and needed more and more memory, and another type of memory was created for them - microSD. Its dimensions are 11x15 mm. This standard size is perfect for all compact devices, completely replacing miniSD. And what’s especially nice is that the size does not affect the class of memory cards: microSD can have the same speed as SD in the same price category. And considering that with the help of an inexpensive microSD adapter you can use compact drives in devices designed for full-size cards, they are the best purchase for the vast majority of consumers today.
Why are memory card classes needed?
The speed capabilities of memory cards have always varied. Some devices simply will not be able to work correctly with a slow memory card (for example, a camcorder will not be able to record video from high resolution, and the professional camera will freeze, taking several pictures and waiting for them to be saved in memory). Therefore, it is important to know that memory will not become a bottleneck in the operation of an expensive gadget.
In order to provide the consumer with the necessary information (and emphasize the advantages of their product), manufacturers began to indicate certain speed characteristics on top-end memory cards. But each manufacturer acted at its best, so we can compare the possibilities different cards It was possible only after purchase.
Then they decided to restore order centrally by introducing into the SD standard such a characteristic as classes of memory cards. Micro SD and SD cards are marked by the manufacturer depending on what write speed the drive is guaranteed to support.
Write speed and read speed
On memory cards you can sometimes see remarkable numbers like "up to 20 MB/s". However, the manufacturer does not indicate that we are talking about read speed, which is almost always higher than write speed. What does it matter? Reading speed affects how long it will take to transfer information from a memory card to a computer. But does it really matter whether you copy photos in five minutes or ten? But the recording speed determines whether your camera/camera will be able to take pictures in real time or will constantly freeze.
That is why, when developing classes of memory cards, SD consortium specialists made data recording speed a classification criterion.
Specific characteristics of individual classes
Speed class is not something complicated. This is just the minimum write speed to the card in megabytes per second. Here are the main classes of micro SD and SD memory cards, indicating their speed capabilities:
- Class 2 - 2 MB/sec.
- Class 6 - 6 MB/sec.
- Class 4 - 4 MB/sec.
- Class 10 - 10 MB/sec.
Since the table indicates the minimum write speed, the actual memory card may have best characteristics. Let's say class 4 corresponds to cards with write speeds of 4.1 MB/sec and 5.8 MB/sec. To know exact value before purchasing it will not be possible.
Speed corresponds to the declared class
It is not enough for the buyer to know what the class of the memory card indicated on the packaging means. I want to be sure that real speed will not be lower than stated. Good news: repeated tests of memory cards from different brands, carried out by both specialists from IT publications and ordinary users, show that the write speed to the card corresponds to the specified class.
This kind of research is not difficult to do yourself. All you need is a card reader (a laptop usually has a built-in one) and a program for measuring the speed of storage devices (it’s easy to find a free one on the Internet). Most exact result will be if you take measurements on a new empty memory card.
If the speed you measured does not correspond to the device class, do not rush to return the memory card to the store. Poor results may be caused by a cheap card reader, problems with the USB port or device driver. It is worth rechecking the measurements on another computer using another reader.
What's next? New Specifications
The tenth speed class of memory cards satisfies the requirements of almost any camera or video camera; most devices do not need this. However, technology development does not stand still, and for some professional cameras, a speed of 10 MB/sec is completely insufficient.
New classes of memory cards have been developed for such devices. Class 16 turned out to be a stillborn child: most users do not need such speeds, but for professional photographers 16 MB/sec is still not enough. But UHS (Ultra High Speed) turned out to be in demand in certain circles and allowed SD cards to compete with top-end Compact Flash. Speed characteristics of UHS-I - from 50 MB/sec, announced UHS-II - from 156 MB/sec.
What memory card speed class do I need?
Obviously, a fast card is better than a slow one. If there are cards of classes 4 and 10 on the market at the same price from trustworthy manufacturers, then it is better to buy one that is of a higher class. However, as a rule, the higher the class, the higher the price, and the difference can be very noticeable. How to make a successful purchase without overpaying?
If the card is used to store and transfer data, like a regular flash drive, then its speed characteristics are not something critical. Of course, with fast card It’s more pleasant to work, so your wallet is the determining factor here.
The class of the memory card for a smartphone, tablet, or player does not matter - for these devices you can easily get cheaper memory. But you need to take a more serious approach to choosing a data storage device for a photo and video camera. Minimum Requirements to the memory card must be indicated in the instructions for your device. As a rule, for a video camera that records video in standard definition, a card of class 2-4 is sufficient, for an amateur point-and-shoot camera - class 6, for HD video cameras and budget DSLRs - class 10, and for a UHD camera or professional camera you may need an expensive UHS card memory.
The time of antediluvian floppy disks has long passed, and they have been replaced by a lightweight and compact USB flash drive. Flash memory is found in all modern electronic devices: players, computers, laptops, cameras, video cameras, and so on. Today we will tell you how to understand all the variety of flash drives that exist, and how to choose and buy the right USB flash drive. Flash memory created specifically for storing information in portable mobile phones. It is universal for almost all models existing today. You can always erase information from flash memory and write new information. Depending on the flash card itself, information can be rewritten up to a million times. Safety information on flash memory almost indefinitely for one human life. It will be stored for up to 100 years. Flash memory is very compact in size: 2-3 cm in length and 3 mm in thickness. At the same time, flash memory is 10 times less susceptible to mechanical damage than a hard drive. You can install a flash card in any electronic devices who support it. Species memory cards there are a lot, but there are even more manufacturers that produce them. And that’s why it’s quite difficult to understand all of this. Buying flash card, be sure to watch it technical description, which must indicate the memory type. If you cannot find the required type of memory for your device, pay attention to special adapters that will help you connect a flash card to all devices. There are 7 main types of flash cards. 1.CompactFlash divided into CF type I and CF type II. They have a high interface speed. The big advantage of CompactFlash is that its size can be increased if necessary. These cards are the most popular due to their low price and decent quality. This card can be used in most electronic devices. 2. IBM Microdrive has Compact Flash type II format. The memory capacity is no more than 1 GB. The reasonable price of such cards makes buyers prefer them over other products. However, the memory medium itself is less reliable, and the energy consumption is quite high. IBM Microdrives do not work in all devices. 3. SmartMedia- This is a very thin model at a low price. Its thickness is no more than three quarters of a millimeter. SmartMedia has a very simple design, but it is inferior to other flash cards in terms of “reliability” of storing information.
