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Memory cards technology

What is a memory card

In brief.

Q. What is a memory card ?

A. A memory card is a small removable storage device for digital cameras to save digital images to, or the digital equivalent of film.

Nearly all cameras use a memory card of some sort to store images. They come in many different sizes, shapes, and capacities.

Compact Flash Type I
MicroDrives (Compact Flash Type II)
SmartMedia (phased out now)
Memory Stick (and variations)
Secure Digital (and variations)
xD-Picture cards

Normally somewhere on the camera there is a small door behind which is a slot in which the memory card fits. The card type will vary depending on the manufacturer of the camera. The images are stored on the card and then downloaded either by the cameras communications cable or by a card reader. Once saved you can then delete so you can start over again.

All the cards have a set speed rating which denotes how fast data can be written to and read from the card. These rates will vary from manufacturer to manufacturer, including a range of faster cards. The more professional the camera the faster the images can be delivered to the card, so a faster card can be used to improve the camera's readiness for the next shot to be taken.

In depth

Not all cameras benefit from faster cards. As a rule the basic compact with no fancy modes or rapid shooting abilities will be just fine with a standard memory card. The mid to high end compact and certainly the SLRs will benefit from faster cards. At present though it is not always possible to find out the rate of which data is passed between your camera and card as, in most cases, it is not published by the manufactures.

Some test have been done for professional SLRs by Mr Rob Galbraith which shows that even some of the SLRs cannot transfer data at more than 3 Mb/sec. So when you buy a card that transfers data at 20Mb/sec, such as the Sandisk Extreme III range, you can see that it is almost pointless purchasing one this fast. The sole reason for buying such an extreme card would be that it carried a lifetime warranty or that you were genuinely going to use it in the harsh temperatures and conditions that is was designed for, but you must of course check first that your equipment will stand up to those extreme conditions.

Help Me Choose.

Make sure the memory card you buy is the of the type recommended in your manual. As long as it is the same type i.e. CF - CompactFlash or SD -SecureDigital etc then the brand should not make a difference, although some brands offer faster cards than others.

Types of card

CompactFlash Memory:

Is the world's most popular removable mass storage device. The Compact flash card is about the size of a matchbook and only weighs half an ounce and connect to products via 50 pinholes arrayed in two rows along one edge of the card.

The card was designed based on the popular PC Card (PCMCIA) standard and can easily be slipped into these slots with the use of a low-cost adapter.

Compact flash technology has resulted in the introduction of a new class of advanced, small, lightweight, low-power mobile products that significantly increases the productivity and enhances the lifestyle of millions of people.

These products include digital cameras, digital music players, desktop computers, handheld PCs (HPCs), personal communicators, Palm PCs, Auto PCs, digital voice recorders and photo printers.

Advanced Features:

High transfer rate for fast copy/download. To date Sandisk Extreme iii cards reach speeds of up to 20MB per second in some devices.
High storage capacity.
Non-volatile solid-state; no moving parts (except IBM Microdrive) maximizes battery power.
Data is not lost when power is turned off.
Operating shock rating of 2,000Gs, equivalent to a 10-foot drop to the floor.
Available in three types: Compact flash Type I, Compact flash Type II and IBM Microdrive.
Consult your device manual for compatibility.
Unfazed by drastic weather conditions ranging from blistering heat to arctic cold.
Compatible with all digital cameras, handheld PCs, digital audio players, and other devices that feature a Compact flash slot.
Available Capacities, 8MB, 16MB, 32MB, 64MB, 128MB, 256MB, 512MB,1GB, 2GB, 4GB.

There are two types of CompactFlash memory card. Type I is the original card, and Type II (IBM Microdrive) is a slighter thicker card with a miniaturized hard disk inside. These cards are normally cheaper in larger capacities but more prone to damage due to excessive humidity or shock. With the solid state Type I cards coming down in price all the time and in larger and larger capacities they may become a thing of the past.

CompactFlash equipment with Type I slots cannot use Type II cards. Equipment with Type II slots can use either Type I or Type II.

Microdrive:

The Microdrive is a thicker version of the CompactFlash type I memory card and contains a spinning hard drive, that was designed to allow for higher memory capacity. A miniaturized hard drive developed by IBM.

Microdrive are available in capacities of up to 1 GB 2GB and 4GB with do doubt larger capacities to come.

The Microdrive's capacity is ideally suited for multimedia or other data-intensive applications that need to be accessed via a handheld device. Whether users are listening to music, watching movies on their PDA or shooting high-resolution photography, the Microdrive enables users to focus on the task at hand--not on the amount of memory available in their device.

The Microdrive is the same thickness as the CompactFlash memory card type II. but a product with a Type II slot is not necessarily Microdrive compatible; please check your owner's manual or the product manufacturer's Web site to be certain.

Because Microdrive's have moving parts, they are less rugged, more heat-sensitive, and require more power than their Type I and Type II solid-state counterparts

Sony Memory Stick

Similar in appearance to a stick of gum, its length is about the same as that of an AA battery used in small portable devices such as headphone players. The shape of Memory Stick is ergonomically designed for easy handling. And, unlike other flash memory cards, it is easy to distinguish the front from the back and the top from the bottom of a Memory Stick to prevent misuse or accidental loss of data. Its small size also allows development of compatible products that are compact and portable.

Memory Stick is a versatile flash memory card that is one of the latest digital data storage solutions in several types of digital devices; including digital cameras, digital music players, digital voice recorders and many other devices that store digital information.

Advanced Features:

High transfer rate for fast copy/download.
High storage capacity.
Non-volatile solid-state; no moving parts maximizes battery power. Data is not lost when power is turned off.
Rugged and sturdy removable media.
Unfazed by drastic weather conditions ranging from blistering heat to arctic cold.
Compatible with all digital cameras, handheld PCs, digital audio players, and other devices that feature a Memory Stick slot.
Available Capacities, 8MB, 16MB, 32MB, 64MB, 128MB.

Is a smaller version of Sony's removable-flash-memory card format Memory Stick, which is roughly the size of a stick of chewing gum. Both card formats were created as storage options for portable consumer-electronics devices.

Memory Stick is used in devices such as handhelds and digital cameras. Memory Stick Duo is about one-third the size of the original, and is meant to fit into devices such as cell phones and small digital audio players.

Multimedia Memory Card:

Multimedia Memory Cards are the small, convenient, and durable solution for data storage use for a variety of digital applications.
These small yet powerful media cards are designed to interface with an array of digital devices designed to support the MultiMedia and SD card format - including PDAs, cellular phones, digital video recorders, and digital cameras.

The card weighs less than two grams and is the size of a postage stamp. The small size of the Multimedia Card is allowing digital device product manufacturers the ability to continuously design ultra-small, portable devices. In addition to its distinct size advantage over other form factors, the Multimedia card's low power draw makes it highly suitable for battery powered mobile applications. The Multimedia card has been designed into products that include digital music players, digital camcorders, cellular phones and global positioning systems (GPS).

Advanced Features:

High storage capacity.
Non-volatile solid-state; no moving parts maximizes battery power. Data is not lost when power is turned off.
Operating shock rating of 2,000Gs, equivalent to a 10-foot drop to the floor.
Unfazed by drastic weather conditions ranging from blistering heat to freezing cold.
Compatible with all digital music players, digital camcorders, handheld PCs, mobile phones and other devices that feature a Multimedia card slot.
Available Capacities 16MB, 32MB, 64MB.

Multimedia Memory Cards come in a range of capacities to suit your storage needs. Multimedia Memory Cards are extremely versatile as they are able to operate not only in devices that have a MultiMedia card slot, but devices that are designed for SD format cards as well.

The normal operation of the device will not be compromised, and you are ensured broader options for use of your Multimedia Memory Card.

Reliability and durability are critical to ensure your data is there when you need it. All Lexar Multimedia Memory Cards are tested and manufactured to the highest quality standards to assure you there is no need to worry about lost or missing data. And with the solid-state design, Lexar Multimedia Memory Cards are the safe, durable, shock-resistant solution for mobile applications and users.

SD memory card:

Storage with peace of mind designed to accommodate a wide range of digital devices, SD memory card feature an erasure-prevention switch. Store your music, photos, and video files with the added assurance that your data can't be accidentally deleted. Just keep the switch in the locked position, and you get safe, secure storage for your digital camera, MP3 player, PDA, cell phone, and camcorder.

SD memory cards are tested under the most rigorous conditions to meet the highest standards of reliability and durability essential to today's mobile users. Similar in form to MultiMediaCards, the small size and solid-state design make the SD memory card the perfect on-the-road performance companion.

SD now come in MiniSD and MicroSD formats for smaller electronic media devices and applications.

xD-Picture Card:

The new kid on the block in memory card media, the xD-Picture Card has been developed by Fujifilm and Olympus to meet the storage needs of digital cameras now and in the future.

xD-Picture Cards are smallest of memory cards, yet have the capability of storing up to 8Gb of data · on a par with some DVD discs!

xD-Picture Cards can also have data written to them · and read from them · faster than other standard media meaning that they are ideally suited to fast storage of image and movie data. Users will also recognise improved performance as image files can be recalled and replayed much faster.

The xD-Picture Card's principal benefits include:

Capacity:

16MB, 32MB, 64MB, 128MB, 256MB, 512MB, 1GB the media's development roadmap shows storage capacity potential of up to 8GB.
Dimensions: 20mm x 25mm x 1.7mm (0.8 x 1.0 x 0.07 inches). This size makes the xD- Picture Card the smallest memory card available.

Read/Write Speeds:

The xD-Picture Card will have one of the fastest read/write speeds on the market.
A 16MB or 32MB card can record data at 1.3MB/sec.
A 64MB card or higher can record data at 3MB/sec and both offer a read speed of 5MB/sec.
These high speeds can greatly enhance the user's experience with a product.
For example, a photographer can take new pictures or view existing images more quickly with the xD- Picture Card media than with other, slower media formats.

Power Consumption:

The xD-Picture Card was designed to use minimal power.
Users will benefit from the convenience and savings of longer battery life on a single charge.

Compatibility:

Adaptors make xD-Picture Cards compatible with other media. A PC card adaptor and a USB card reader will be available for the x D Picture Card at the time of launch.
A CompactFlash· adaptor will be available later.

Branding:

Fujifilm, Olympus. Both development partners will offer individually branded xD-Picture Cards at launch but the technology will be made available to other companies.

SmartMedia Memory Card:

Currently no new cameras are made with SmartMedia as its storage medium.

Smart media (SSFDC) memory cards provide mobile data storage in a very small inter-changeable format. SSFDC consists of a single NAND flash EEPROM chip embedded in a thin plastic card. It can be transported between digital systems including consumer and portable electronic devices, PDAs, digital cameras, pagers, MP3 digital music players and more.

Advanced Features:

High transfer rate for fast copy/download.
Multiple storage capacity.
Unfazed by drastic weather conditions ranging from blistering heat to freezing cold.
Available Capacities, 16MB, 32MB, 64MB and 128MB.

*Be sure to check the maximum capacity your camera supports.

Card Maintenance

It is very important to look after your cards, they are your lifeline, if your card goes wrong you won't be taking any pictures. The card is just like a hard disk and has a file structure and can suffer with fragments of left-over files hanging around in dusty corners of the cards memory which can, if left, result in less images being saved and could end up causing a corrupt file.

As a rule cards can be corrupted by:

Not letting either the camera or card reader finish processing data before removing the card.
A loss of or no power to either card reader or camera whilst reading from or writing to the card.
Switching modes on the camera whilst processing data.
Copying any other form of data to the card other than images. This can confuse the camera and may cause errors if it sees data it cannot understand.
Anything that will interrupt data processing.

Below is a general housekeeping tip.

Your memory card, whatever the format, is vulnerable to the same problems as the hard-drive in your computer, this is why most operating systems arrive prepared with disk utilities that de-fragment data and correct the FAT (File Allocation Table) on the disk. Many people do not realise that the memory card once installed onto a PC can be treated in exactly the same way as you would the hard drive. This means you can run Scandisk, Norton Disk Doctor or Format on your card and any errors will be corrected or communicated to you.

After prolonged use the file fragments build up on the card, this usually results in less capacity, minimising the amount of photos you can take on a single shoot. It is seen as very good practice to format your card on a regular basis, at least once a week! This cleans the card of any fragments and replaces the directory structure, with this type of regular servicing you will rarely experience problems.

A summary of steps below will help keep your card in tip top condition and minimize the loss of image.

Always reformat the card in your camera each time after downloading and saving the pictures on your computer.
Always create a backup by saving your files from the memory card to your computer.
Always charge your batteries as failure during a shoot will result in the corruption of data on the
card and can even lead to a damaged card.
Do not remove the card from the camera or card reader too quickly as this can result in the
corruption of data on the card and lead to damaged memory areas.
Wait a few seconds before shutting off the camera while the camera is still saving data to the card, wait for a few moments to ensure that all the data has been written to the card.
Avoid large static charges, and be extra careful when handling cards in dry, low humidity areas.
Keep cards away from strong magnetic sources, and extreme heat and cold. Walk through airport x-rays and scanners are safe but be careful of the stronger x-ray equipment used to examine checked baggage.
If using Windows 2000 or XP always flush the cache before removing your card from the reader, this can be done by right clicking on the green arrow in the system tray and ejecting your drive letter
When editing pictures in your graphics application always ensure you have moved the picture from the card to your computer first, you will dramatically increase the life of your card by doing this.
If a memory card problem occurs, stop using the card immediately, do not reformat the card or delete pictures - use ImageRecall's "Dont Panic" software
Be careful with the "delete all" and "Format" functions on cameras using Smartmedia or XD card as they are irreversible formats that cannot be recovered by anybody.