Posted by Eric Huang on March 24, 2013
On my last Ski Vacation, I overfilled my GoPro video camera with videos. I used a 32 GB SD card. I have 3 32GB SD Cards. I decided to stop buying them because I don’t want to keep buying cards. I know several people who just buy the cards, and store them forever.
I have a box full of 1394 and USB Hard Drives at home. I don’t want any more hard drives to store, I’m okay with collecting SD cards because they are small and cheap, but if I start collecting lots of SD cards, I’m back to collecting lots of physical media, which I don’t really want to do. I want to catalog all my pictures and video in one easily accessible place on my PC and ultimately in the cloud available to all my devices.
I really want to rapidly off load all my videos on a PC (or tablet) for fast editing and move to my next task. If I transfer videos off my 32GB drive right now, it takes a solid 20 minutes for just 8 GB of video. This is about 80 minutes of video.
This is because the SD Card Reader in my PC is rate limited by the data rate of SDIO and the read speed of the SD Card itself. If it’s cheap SD memory, it will take longer to read the data than the more expensive SD memory. The SD memory I purchase is Class 10 which means must be able to read from or written to at least 10 Megabytes per second or about 80 Megabits per second.
Which turns out to be slower than the 320-350 Megabits per second effective throughput speed of USB 2.0.
Which means, my transfers are rate limited by the cheap NAND flash used in the Class 10 SD Cards I buy. So I wait for 20 minutes to transfer all that data, rate limited by the SD Card, not USB 2.0.
Certainly there is a market for this kind of customer who enjoy or don’t care about transfer speeds. There must also be consumers for fast transfers. We don’t want to wait 20 minutes, or longer. Especially if I’ve recorded more video than I recorded.
So you might ask, why bother with USB 3.0 if USB 2.0 is already faster than SD Cards can allow.
The reason is this:
Camera makers can embed flash memory in the Camera that is faster than SD Card memory and supports USB 3.0 speeds.
Video Camera and Digital Still Camera makers should EMBED fast flash memory. It should be included. Then the SD Card Memory isn’t the rate limiting factor. The cool thing is that Camera Makers make MORE money, not less, with no change to their chips.
More on why tomorrow, and maybe some economics.
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Our PHY Guy Goes Crazy over a Tea Cup
Gervais Fong went nuts over this Tea Cup at a customer site today.
So you know what to get him for his birthday now.
Please congratulate me on that terrific transition to get you to our PHY web page.
More on the economics and how digital camera makers get make more money embedding more memory.
Before my next Blog, feel free to explore the 5 blog entries below.
Part 1: Intro to NAND
Part 5: The Wrong Question