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This is the first installment of a new Category we’ve added here at eTechTour.com. What we hope to achieve with these “Demystifying Data” sections is being able to shed some light on some of the Tech questions that a lot of people have. Things like what are the differences between two similar technologies, or what something really technical really means or what it should mean to them as a consumer.

To start us all out, I thought we’d have a quick segment showing the difference between a couple types of Memory Cards that are commonly used in camera’s. We all know SD, but what about those seemingly random things like XD, or CF or Sony’s MS. We hope you enjoy the insights and will follow along in the future! (If you have any requests, make sure to comment at the bottom or send in a request from our Tip Us page!)

Demystifying Data – Memory Card Edition

A good place to start in this series is with the most common of the memory clan. The good ole’ SD (Secure Digital) Card. SD Cards are widely used in digital cameras, camcorders, handheld computers, netbooks, PDA’s, cell phones, GPS’s, video games and even media players. SD cards have evolved numerous times since 1999 when they were first created by SanDisk, Matsushita and Toshiba. This evolution has led to different offspring of the original SD card, but in simple terms, all the variations of SD cards just mean more memory and faster writing speeds.

The original SD Cards could hold up to 2GB on a card and as with all different types of SD cards can vary in “Class”. A class is essentially a rating that tells how fast the card can transfer data in terms of speed like a CD-Rom would.

Following standard SD cards were SDHC which could hold up to 32GB of storage and caused quite a bit of confusion as SDHC cards are not compatible with most older technologies that only used standard SD. SDHC equipment is backwards compatible so they can use the older memory cards however.

Finally we now are at SDXC which can theoretically hold up to 2TB of data (currently the highest we’ve seen is a 64GB card) and these will be backwards compatible with the other SD cards.

Rating Write Speed
(Mbit/s)
SD Class
7.2
10× 12.0
13× 16.0 2
26× 32.0 4
32× 38.4 5
40× 48.0 6
66× 80.0 10

The next type of memory card we’re looking at is the XD (Extreme Digital) Card. This type of card is used mainly in digital cameras. They were developed by Olympus and Fujifilm in 2002. Currently XD cards are only available in 16MB to 2GB sticks.

These memory sticks come in a couple different Types which only provide different speeds when reading/writing to them (classified as Standard, M, H and M+)

The H was the fastest of these types but was discontinued due to higher costs for production to leave the future of XD with M+ (which is slightly slower than the H type)

Currently there are no more cameras that are made that ONLY support XD meaning it is still a relevant storage type, but no longer seeking real growth or competition.

Type Write speed
(MiB/s)
Read speed
(MiB/s)
Standard 1.3 5
3 5
M 2.5 4
H 4 5
M+ 3.75 6

CF (Compact Flash) are used in a variety of electronic devices and was first introduced in 1994 by SanDisk. CF was the memory card of choice when it first came out. Beating out other memory options like Miniature Card, Smart Media and PC Card Type I. But it found big competition when other Memory stick formats like SD and XD came into the picture as these are typically much smaller and have the same capacity as CF.

CF are still very relevant and used in many mainstream commercial products to date such as Sony’s HVR-MRC1K tapeless video recorder.

They are available in many different capacities ranging anywhere from 64MB to 100GB.

Generally CF are considered more durable and rugged than other memory sticks. Since they are larger, it’s also not possible to put them in very slim devices, but on the plus side they cannot be lost as easily.

The last memory stick that will compete today is the Sony Memory Stick. Sony introduced these in 1998 and it has now spun into a family of many types including the Memory Stick PRO (more storage and faster speeds), Memory Stick Duo (smaller form factor of the memory stick/pro), the Memory Stick Micro (M2) and lastly the Memory Stick PRO-HG which is made for use in High Definition still and video cameras.

Unlike the others, the Sony Memory Stick is mainly used for only Sony Products (cameras, laptops, PSP’s etc) and just recently Sony has started designing these products with both readers for Sony Memory Sticks and SD cards. Sony however is not quitting development of the Sony Memory Stick.

The original Memory Stick  could hold 4MB to 128MB and is no longer produced. The Memory Stick PRO has a theoretical capacity of 32GB but mostly can be found with 4GB. These new sticks introduced a new thing called High Speed mode which would allow much faster transfers of larger files.

The memory stick Duo and PRO Duo were created to fill Sony’s need for a smaller memory card for cameras and PSP’s. They inherit the same characteristics are their larger siblings but just on their own smaller scale.

The final Memory Stick the Micro (M2) was a joint effort with SanDisk in 2006 and comes in any format up to 16GB capacities. These were mainly used for Sony Ericsson phones that needed a much smaller memory card for the real estate.

So there we have it folks, I hope that helps clear some information up on the different types of memory cards and why we have them. The main card now is still the SD card and it shows no real sign of changing, but there are alternatives for those who want them. Just be careful next time you’re purchasing a camera or something similar because you may not want to have to go buy everything all over again!

Don’t forget to drop a comment and let us know if you have other questions about technology or other topics you’d like covered on Demystifying Data!

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