Enter section Digital project--CF Card

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[Concept]

    CF card (Compact Flash) originally is a method for a data storage device of the portable electronic device.

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[History]

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    Produced by SanDisk Corporation in 1994 for the first time and to develop the relevant norms. This, its physical format has been adopted by a variety of devices.
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    CF is the larger size PCMCIA Type I Memory Cards competition appears earlier and the first flash memory one of the criteria, it was initially established on the basis of the NOR-type flash memory in Intel, and then changed to use with non-type flash memory.

    CF is one of the oldest, most successful standard, especially for the professional camera market.

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    It has a longer life than the other stored, and a lower unit cost of capacity in the smaller sizes, but can also provide a larger capacity.

    Because less than the newer non-type flash memory, CF card or flash storage density is the largest volume in the early 1990s, three storage card (the other two being Miniature Card-MiniCard and SmartMedia card) , CF card after the switch with flash

    At that time, IBM Microdrive not use solid state memory.

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[Principle]

    As a storage device, which revolutionized the use of the flash

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Classification

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From the [Shape] points

    Type I card / II type card

    The electrical characteristics of CompactFlash smaller than, but consistent with PCMCIA-ATA interface.

    The connector of 43 mm width, and the depth of the housing is 36 mm, and a thickness of 3.3 mm both (CF I-type card) and 5 mm (CF type II card).

    CF II card slot can be used for CF card type I, CF II cards can not be inserted due to the relationship between the thickness of the CF Type I card slot.

    The CF Card majority CF I card.

    CF type II card slot for mini hard drives and other devices.

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From the [speed] points

    CF card, high-speed CF card (CF + / CF 2.0 specification), CF 3.0

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[Features]

1. CF card than early PC Card (PCMCIA) I-finer, however, the thickness of the same and I and Type II PC Card.

    CF card is among the most successful of the early memory card formats, popularity than Miniature Card, SmartMedia Card and PC Card Type I in mainstream.

    Applications in smaller equipment, SmartMedia cards used to be the main competitor of the CF card, CF card market penetration even once beyond.

    However, SmartMedia advantage of the new format the memory card is terminated (circa 2002-2005).

The memory card formats (such as SD / MMC, various Memory Stick, xD Picture Card, etc.) 2. Late nineties to the early 2000s with fierce competition.

    Volume ratio of the new memory card CF card several times, to a certain extent with the CF than PC Card bigger difference.

    New formats would dominate handheld computers, mobile phones and consumer-grade digital cameras, especially the super-mini model.

3. CF card with PCMCIA-ATA functionality and compatible; CF card weighs only 14g, only a matchbook-sized (43mm x 36mm x 3.3mm) is a solid product, that is, no moving parts work.

4. CF card using flash memory (flash) technology, is a stable storage solution, which does not require a battery to maintain stored data.

    For the saved data, CF cards are higher than traditional safety and protection of the disk drive;

    5 to 10 times higher reliability than the conventional magnetic disk drive and type III PC card, and the electricity consumption of the CF card is a small disk drive, only 5%.

5. CF card at the same time support a voltage of 3.3 volts and 5 volts, any one CF card can work in both voltage, which makes it a broad range of use.

    CF memory card compatibility is also reflected in the Flash Memory storage module and controller combination, such external device using the CF card can be done relatively simple and different CF card can use a single agency read and write, do not have to worry about compatibility issues, especially in the upgrading of the CF card can also be to ensure the compatibility of the old equipment.

    These excellent conditions makes the most of the digital camera to select the CF card as its storage media of choice.

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Capacity

    Pretec CF cards, released several good capacity of 32GB, 64GB and 100GB

    32GB advertised speed of up to 333 speed of up to 50MB per second write; 100GB version is 233 times per second 35MB write; 64GB can be used in CF to SATA
The use additionally an adapter box containing four Pretec 64CF, becomes the SSD.

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[Development platform]

    CF card has considerable multi-platform support, including DOS, Windows 3.x, Windows 95, Windows 98, Windows CE, OS / 2, Apple System 7, Linux and Xu
A variety of UNIX are able to support.

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[Disadvantage]

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Limited capacity of 1. []

    Capacity improved several times, but still not be able to catch up with the development of the digital camera pixels.

    Million pixels or more products have the minimum specifications of the popular high-end products, while the the civilian mainstream market also 8 megapixels levels.

    The ordinary civilian JPEG compression format, the capacity is acceptable, but the professional level TIFF (RAW) format or does not fit a few image data.

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2. [Larger]

    Compared with other types of memory card, CF card volume slightly too large, which also limits the volume of digital cameras use a CF card, CF card holds many lessons for popular ultra-thin digital camera mostly gave up, switch to a more compact the SD card.

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3 [performance limitations]

    CF card Operating Temperature 0-40 degrees Celsius.

    Environment below 0 degrees, the basic digital camera can be said to become a "waste". Even if it is a professional machine was not spared.

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[CF Card 5.0 standard]

    Theoretical maximum capacity of 144 million GB

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1 CF Card Alliance (CompactFlash Association, CFA) announced recently passed CF5.0 version of the standard, the new standards make existing CF4.1 version of the standard based on a number of upgrades, especially in the rapid rise of the flash memory capacity situation, CF5.0 capacity limit several orders of magnitude.

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2 and 137GB of hard drive capacity limit a few years ago due to the use of 28bit addressing current CF card, the maximum capacity is only 137GB. Therefore, in CF5.0 standards, addressing space is added to 48bit, theoretical maximum capacity is raised to 144PB (144000TB) should be able to in a very long period of time to meet the demand.

    In addition, the new standard for data transmission units from 128KB to 32MB, greatly improving the transmission efficiency.

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3. CF5.0 standard supports ATA-6, and ATA-8/ACS-2 standard and modified in order to improve the compatibility of electrical definition of the interface.

    And similar to the SSD CF5.0 standard also increases the TRIM function to be able to manage the free space and improve performance.

    In addition to the established norms, CF5.0 also provides an optional feature "Video Performance Guarantee" (Video Performance Guarantee) QoS features HD video capture for the large amount of data, no dropped frames. By the introduction of the functions, the the CF Card intention to enter the ultra-high-speed photography and professional video markets.

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【Article is excerpted from: Baidu Encyclopedia】
【Network reprint / Just reference】
【Translation is by Goolge】