Buying guide: Memory card
While you carry on clicking snaps on your prized Digital camera, you suddenly find that you’ve just run out of space for more! Quite a familiar situation, right? A similarly perturbing situation is when the data or the file that you want cannot be downloaded to your computer because there’s simply no more space. These are some instances where an additional memory card proves beneficial. This guide provides you with all the information that you need to never go wrong when purchasing memory cards.
Essentially, a memory card or a Flash memory card is a data storage memory chip used as additional memory for digital media devices such as PDAs, mobile phones, laptops, etc. Flash memory (also known as Flash RAM or Random Access Memory), is a type of re-writable memory chip. It is a form of EEPROM (Electrically Erasable Programmable Read-Only Memory) chips. Unlike a computer’s RAM, a flash memory is Non-Volatile Random Access Memory (NVRAM). Meaning, it retains stored data even when it is powered down. It is named “FLASH” memory because a section of memory cells on the microchip get erased in a single action or in a “flash”. Flash memory is usually found in memory cards, digital cameras, MP3 players, mobile phones et al.
Listed below are types of memory cards or media cards commonly available:
¨ PC Cards: PC cards (Personal Computer cards) are interchangeable peripherals used as extra storage media usually in laptops. Previously, these were known as PCMCIA (Personal Computer Memory Card International Association) cards. Quite recently, they were renamed as CardBus. These function as flash memory, modems, network interface cards, and SCSI disk controllers. The CardBus or PCMCIA is currently being developed as yet another peripheral specification for notebooks known as the ExpressCard.
¨ Compact Cards: A Compact card (also CF card) is a removable data storage memory chip based on the flash memory concept. Developed by SanDisk Corporation in 1994, it is still used in several portable devices such as mobile phones and PDAs. Two types of compact flash cards are widely seen — CF-1 or type –I, which is 3.3 mm thick, and the CF-2 or type –II, which is 5 mm thick. IBM manufactures the “Micro-Drive” card —quite similar to the type-II card. It uses a hard drive type assembly construction instead of a flash memory chips. Compact memory cards allow storing limited megabytes of data earlier. However, nowadays they provide several gigabytes of data storage space. The new and improved CF+ card variety provides up to 137GB of space!
¨ Smart-Media Cards: Toshiba developed and launched the Smart-Media (SM) flash memory card in 1995 for competing with Mini-cards, Card-bus, and CF cards in the market. This SSFDC (Solid State Floppy Disk Card) is less than 1mm in thickness, and uses 16Mbit to 64Mbit flash memory chips for providing storage capacities of up to 2MB to 128MB. The data transfer rate in a Smart-Media memory card is approximately 10, 00,000 read/write cycles, and stores data for about 10 years without requiring any power.
¨ Memory Stick: In 1998, Sony developed the flash Memory Stick format, which is about as thin as a strip of chewing gum. Almost all Sony products — cellular phones, PDAs, laptops, digital cameras, and the PlayStation gaming console series have an only slot for a Memory Stick (MS) for saving data or “save games”. This memory stick provides storage capacity from 4MB to 256MB, and a data transfer rate of up to 20MB/s. Recently, Sony has rolled out latest versions — the Memory Stick Pro, Memory Stick Duo, Memory Stick Pro Duo and the Memory Stick Micro, which support larger storage capacities of 2GB while being much thinner. It also has a write-protect switch or a “notch”, which prevents accidental data erasure or over-writing. The memory card ps2 is a fine example of gaming oriented memory card.
¨ Multimedia Card: Toshiba developed the MultiMedia Card, known as MMC. Currently, it is one of the most popular storage mediums, being extensively used in cellular phones and portable MP3 players. With data capacity of 1GB and above, operating at 1.8 volts, this card is cost effective and saves a lot on your devices’ battery power. It also makes data transfer quite easy. Today, several computers, especially laptops provide a slot for MultiMedia Cards. Developed and launched in 2004, the Reduced-size MultiMedia Cards or RS-MMC is a revised version of the MMC.
¨ Secure-Digital Card: The introduction of Secure-Digital (SD) flash memory card is slowly taking over MultiMedia Cards in terms of popularity. As the format of this card is based on DRM scheme (Digital Rights Management) — a feature not present in MultiMedia Card — the SD memory card is much faster and secure. Its data storage capacity is 2GB and above, and most laptops and motherboards come with a built-in Secure-Digital card reader slot.
¨ Mini-SD Card: In 2003, SanDisk Corporation unveiled an upgraded version of the SD card. Mini-SD cards sport storage capacities ranging between 16MB and 4GB.
¨ Micro-SD Card: A Micro-SD card is an “ultra” small flash memory card. Also known as TransFlash memory card or micro memory card, it is known to be the world’s smallest flash memory card as it is sized smaller than a fingernail. As of April 2006, Micro-SD cards are available with storage capacities ranging between 64MB to 32GB. Though, primarily used in cellular/mobile phones, due to its extremely small size and big storage capacity, the micro SD memory card is also implemented in handheld GPS devices, portable audio players, etc.
¨ XD-Picture Card: In 2002, Olympus and Fujifilm jointly developed the xD-Picture (eXtreme Digital Picture) flash memory card in the market. Nowadays, it is available in the following storage capacities: 64MB, 128MB, 256MB, 512MB, 1GB, 2GB, and 4GB. Actually, this flash memory card is the de facto storage media for entry-level to high-end digital cameras. Since they are faster in comparison to the SM, MMC, MS cards, they are a bit more expensive too, than other flash memory media cards.
With so many choices of memory cards at your disposal it is rather baffling to arrive upon a decision, in case of purchasing one. What features or specifications should one look for? Here are some features and guidelines for helping you in making the right decision when buying a memory card that suits your needs perfectly:
¨ Storage Capacity: The storage capacity is the primary factors that determine the type of memory card required. With differing types, the capacity of a memory card varies. Nonetheless, the preferred capacity will depend upon your intended usage and budget. A 2GB memory card or cards with more than 2GB storage will satisfy most basic storage needs.
¨ Operating voltage: It is the voltage of the battery when operational. Low voltage leads to lower power consumption, thereby preserving battery life for longer use. Certain flash memory card support operating on two different voltages. Most memory cards come with an operating voltage of 1.8 volts or 3.3volts, whereas few support dual operating voltages of 1.8volts along with 3.3 volts, or 3.3 volts and 5 volts.
¨ Size and Weight: Memory cards provide portability; hence they are small in size. Memory cards sized as a tiny matchbox or the size of a thumbnail, the smaller the flash memory card the better. They weigh anywhere from 15 grams to as low as 0.4 grams. The size and the weight of a memory card also determine the type of card suitable for use.
¨ Cell Endurance/durability or write and erase cycle: The number of times you can erase and write data per block on a memory card is known as the “durability” of a memory card. Usually, majority of the memory cards can be written to and erased from for up to 100,000 times per block.
¨ Drop Shock/Operating Shock: This is a precise numeric quantity of vibration measurable that a memory card can withstand when in use, and even when not being used. A majority of flash memory cards can withstand an operational (in use) shock of up to 1000G-2000G, which is equivalent to being able to withstand a freefall drop or throw from up to 5-10 feet.
¨ Operating Temperature: Almost all flash memory cards can withstand operating temperature from -13F / -25C to +185F / +85C.
¨ Transfer Bandwidth/Transfer rate: This is the speed of data transfer provided by a flash memory card. As opposed to denoting by bits and bytes per second, a flash memory card’s speed is nowadays expressed by a quantity of ‘X’, i.e., the number of bits or bytes of data transferred in this case ‘X’ transferred per second. The standard dictates “x1” to be about 0.15MB/sec or 1.2288Mbps. A majority of memory cards provide a bandwidth of x1, x4, or x8 Bus Width (Bus Width is the data transmission speed on a computer’s internal data transfer buses).
¨ Compatibility: The memory cards find use in various kinds of devices such as cellular phones, PDAs, laptops, etc. Whatever might be your need, it is important that you should check if the memory card is compatible with all the devices that you intend to use it with. Usually, several flash memory cards are compatible with almost all types of devices.
¨ Data Retention: This is the period for which a memory card can hold or store data without requiring any power. It is also known as the memory card’s operational lifetime. As a rule, in case of normal usage, the data retention time for a memory card is for a minimum of 10 years or so. Few flash memory card manufactures claim an operational lifetime of up to 100 years.
¨ Warranty: A warranty of 5-7 years on flash memory cards is now a standard feature.
In case of accidentally erasure or damaging of the stored digital images on the flash memory cards and you do require them all again, few applications provide for recovering the lost digital content on your memory card. Memory cards give you that extended benefit for storing extra data, transferring digital media in a “FLASH”, and carry it anywhere, anytime!
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