Memory cards are a popular storage medium for many of today's consumer electronics devices, including digital cameras, cellphones, hand held
Common Types of Memory Cards
The PCMCIA standard has been expanded several times and are suitable for many types of devices. There are three types of PCMCIA cards. All three have the same rectangular size (85.6 by 54 millimeters), but different widths:
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Type I cards can be up to 3.3 mm thick, and are used primarily for adding additional ROM or RAM to a computer.
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Type II cards can be up to 5.5 mm thick. These cards are often used for modem and fax modem cards.
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Type III cards can be up to 10.5 mm thick, which is sufficiently large for portable disk drives.
devices and other small electronic devices. Flash memory is nonvolatile, that is the memory card will not lose its data when removed from the device, and the cards can also be erased or reformatted and reused.
For most consumers, when buying a memory card you have to consider price, capacity and compatibility. Some devices will support up to a specific size of memory card, and a specific type of memory card as well. Its important to read the information that came with your device to ensure you purchase a memory card that will work in your device.
There are a few major types of memory cards that can be
SD cards are used in many small portable devices such as digital video camcorders, digital cameras, handheld computers, audio players and mobile phones. In use since 1999, SD Memory Cards are now available in capacities between 16 Megabytes and 1 Gigabyte, and still growing. An SD card typically measures 32 mm x 24 mm x 2.1 mm and weighs approximately 2grams.
Sony Memory Sticks
Sony Memory Sticks are light, compact and designed for a wide variety of devices including digital cameras, recorders, and more. With the use of an adapter most Sony Memory Sticks can be used with almost all Memory Stick PRO compatible products.
- Memory Stick Micro (M2): 15 mm x 12.5 mm x 1.2 mm
- Memory Stick PRO: 50 mm x 21.5 mm x 2.8 mm. The Memory Stick PRO format has an an 8-bit parallel interface with theoretical transfer rates up to 480Mb/s. It is commonly used in high megapixel digital cameras and digital camcorders.
Types of RAM
The following are some common types of RAM:
- SRAM: Static random access memory uses multiple transistors, typically four to six, for each memory cell but doesn't have a capacitor in each cell. It is used primarily for cache.
- DRAM: Dynamic random access memory has memory cells with a paired transistor and capacitor requiring constant refreshing.
- FPM DRAM: Fast page mode dynamic random access memory was the original form of DRAM. It waits through the entire process of locating a bit of data by column and row and then reading the bit before it starts on the next bit. Maximum transfer rate to L2 cache is approximately 176 MBps.
- EDO DRAM: Extended data-out dynamic random access memory does not wait for all of the processing of the first bit before continuing to the next one. As soon as the address of the first bit is located, EDO DRAM begins looking for the next bit. It is about five percent faster than FPM. Maximum transfer rate to L2 cache is approximately 264 MBps.
- SDRAM: Synchronous dynamic random access memory takes advantage of the burst mode concept to greatly improve performance. It does this by staying on the row containing the requested bit and moving rapidly through the columns, reading each bit as it goes. The idea is that most of the time the data needed by the CPU will be in sequence. SDRAM is about five percent faster than EDO RAM and is the most common form in desktops today. Maximum transfer rate to L2 cache is approximately 528 MBps.
- DDR SDRAM: Double data rate synchronous dynamic RAM is just like SDRAM except that is has higher bandwidth, meaning greater speed. Maximum transfer rate to L2 cache is approximately 1,064 MBps (for DDR SDRAM 133 MHZ).
- RDRAM: Rambus dynamic random access memory is a radical departure from the previous DRAM architecture. Designed by Rambus, RDRAM uses a Rambus in-line memory module (RIMM), which is similar in size and pin configuration to a standard DIMM. What makes RDRAM so different is its use of a special high-speed data bus called the Rambus channel. RDRAM memory chips work in parallel to achieve a data rate of 800 MHz, or 1,600 MBps. Since they operate at such high speeds, they generate much more heat than other types of chips. To help dissipate the excess heat Rambus chips are fitted with a heat spreader, which looks like a long thin wafer. Just like there are smaller versions of DIMMs, there are also SO-RIMMs, designed for notebook computers.
- Credit Card Memory: Credit card memory is a proprietary self-contained DRAM memory module that plugs into a special slot for use in notebook computers.
- PCMCIA Memory Card: Another self-contained DRAM module for notebooks, cards of this type are not proprietary and should work with any notebook computer whose system bus matches the memory card's configuration.
A memory card or flash memory card is a solid-state electronic flash memory data storage device capable of storing digital contents. These are mainly used with digital cameras, handheld and Mobile computers, mobile phones, music players, digital cinematography cameras, video game consoles, and other electronics. They offer high re-record-ability, power-free storage, small form factor, and rugged environmental specifications. There are also non-solid-state memory cards that do not use flash memory, and there are different types of flash memory.Data table of selected memory card formats
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