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Old Jul 16, 2002, 4:08 PM   #1
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Default Interesting charts on Flash cards

USA:
o 42% CF
o 31% SM
o 22% MS

Japan:
o 29% CF
o 46% SM
o 21% MS

Look at the growth curve:
http://www.palminfocenter.com/forum/...?TOPIC_ID=5341
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Old Jul 18, 2002, 2:20 PM   #2
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Curious. I'd guess that it might be because more consumers in Japan have gone to digital for snapshots. For that use 128mb cards are just fine but it's a choke point for many of us.
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Old Jul 18, 2002, 3:45 PM   #3
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I think the far east prefer 'smallnest' because of their custom (or small hands), and it's also the homebase of Smartmedia (CF camp is championed overhere by Sandisk through their CFA association...) Also in theory the Smartmedia could be made cheaper since it's just the raw flash dies ganged together; whereas the CF requires a HD like controller built-in to the card.

All that said however, this market is booming and the simultaneous addition of both the new XD and MemoryStick DUO formats add even more to the confusion !!! (I just have to explain on the forum what CF I & II means)
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Old Jul 28, 2002, 12:45 PM   #4
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Default How Many Flash Types?

Two(2). I have posted this info before on Steve's old board, but it seems like lots of newbie missed this, and here's it is again:

There's just two types of flashes 'NOR' and 'NAND'. 'NOR' flash is what most people are familiar with and goes on the processor parallel bus just like a BIOS in PC, or the firmware in all existing digicams. Theses type of flash are fast (albeit much slower than the PC100), and are manufactured by almost anyone including Intel (StrataFlash) and AMD (Boot-Block). However theses devices are not very dense (there was actually a world shortage on theses flashes since they also go into every cell phones), and are more reliable than the next type, which we'll go into. Theses parallel flashes are also much more expensive because of their very critical location on the processor bus, and would be probihitive if used for mass storage.

... and then we have the cheap 'NAND' flash, this type is used in almost every single digicam as removeable films. Theses 'NAND' flashes are much denser hence lower in cost, but are only manufactured by a handful of huge conglomerates in the far east. There's a caveat however in that all theses 'NAND' type flashes are accessed in a serial fashion just like a hardisk for their price advantage (ie a command is send, the address, and then the string of data). Theses 'NAND' flash can be bonded out to a SmartMedia form factor and can be used as is (the firmware in the camera will handle the protocol translation). Compact Flashes (CF) take theses 'NAND' flashes one step further by integrating the raw memory cells with a controller chip in the old day (or lower density flashes) to make them conform to the PC's ATA hardisk interface. With higher density ones, nowday the controller are fully integrated together with the memory cells on one die!
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Old Jul 28, 2002, 12:47 PM   #5
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Default How Fast is Flash? (vs microdrive)

While no speed demon all flashes can be read pretty quickly, but their much slower write time is of concern and varies widely. Each manufacturer's process also varies from one another and so are all their write algorithms. To complicate things a memory location in a flash can not be randomly written over like a Random Access Memory, but a whole block need to be erased first and re-written even though just one location need to be changed... For example, to change a picture in a block, every pictures in that block need to be erased first and rewritten! That's the nature of all flashes and that's why they are slow during writes (but guess what the vendors usually advertise?). Sure enough at x24 read speed they approach a microdrive... This is just blocks, shall we go into flash paging as well? (this explain why the microdrive is also faster on larger files over CF). Some vendors even specs their write speed in the PIO mode which is faster, but meaningless, since most write access (beside the FAT) are the DMA types.
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Old Jul 28, 2002, 12:48 PM   #6
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Default Flash Last Forever?

Just like any dense low-cost consumer electronics most flashes are built with defects (just like dead pixels in CCDs) which the software must then masked out. One bad single bit can be masked out with ECC, while larger defect just get remap (ie no different than a hardisk). This is the very nature of the beast and will increase with the flash lifetime (just like CCDs). Also flashes erased/write cycles are limited and specs with a limit in all datasheets, but let's not forget about the above block erase/write cycles limitation. One million cycles seems like a lot, but divide this number by 5/10 or more and it'll be more concerning... File Allocation Table for one in the DCF that all flashes use (and we all know how MSFT is good at managing DOS) will be the most affected, so those 'ERR' that get reported once in a while in this forum, especially older devices, may be legit after all and not all due to fat-32 formatting. May be they are just reaching their EOL.

[Edited on 7-28-2002 by NHL]
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