02-04-2012, 08:58 AM | #1 |
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To the SD-card users: Why ...
... do you use an SD-card?
I've read a lot of people have problens with their SD-cards. The question is why would you use one if the reader itself has enough memory to last you for several months worth of reading? I'd also think the battery life would be impacted by using an SD-card. For me there's absolutely no reason whatsoever to use an SD card in the KT. Just my 2 cents Aydan |
02-04-2012, 10:03 AM | #2 |
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When I reset the KT, the ebooks on the SD card are not lost.
I use some programming manuals, which are PDFs and pretty big, so using a SDcard is handy. I like to keep the Linux OS (which the KT uses) with as much freed up storage as possible for it to operate. There's absolutely no problems using an SD card that uses 2GB storage. It's operates just as well as using the onboard storage. I can swap out SD cards as much as I want with different cards, been thinking of using another SD card for different genres of books, as currently there's no way to separate different genres into different folders. |
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02-04-2012, 10:17 AM | #3 | |||||
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Only some databases and stuff like that are on the same partition. Quote:
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But that seems to be dependant on how people use the Kobo. I only have about 30 Books on it. Too much already, really. But as I said, I don't jump between books. I read one after another. Regards Aydan |
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02-04-2012, 10:27 AM | #4 | ||||
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I don't have to mess with loading stuff in and out of Calibre, far easier to have lots of books on the SD card and if a reset is required, I still don't have to do anything. Quote:
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IMO the KT gets more buggy the more you mess with it. Quote:
Anyway, Just answering your question, I can't be really bothered debating about it tho tbh, I'd rather be reading.. Last edited by danskmacabre; 02-04-2012 at 11:02 AM. |
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02-04-2012, 12:53 PM | #5 | |
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2. For a backup, if I go anywhere for a few days I'll load the books that I'm reading onto a SD card just in case I have to do a reset. |
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02-04-2012, 01:44 PM | #6 |
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02-04-2012, 01:49 PM | #7 |
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02-04-2012, 03:37 PM | #8 | |
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If I only read books once it would be easy to limit the number of books on my Kobo to 30 or 40. However as I reread my books I would prefer to keep 300 to 400 books on it as I like to be able to browse and choose something at random - just like I used to do with my real books. When loaded with that many books the Kobo is very sluggish. I have also found it necessary to do multiple resets which is fine when you are at home with access to Calibre or Adobe or your Kobo desktop but when you are away losing all your books is a disaster! |
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02-04-2012, 03:48 PM | #9 |
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Well, some people are paranoid about the internal battery dying... I haven't had that problem yet, but I've had several devices which suddenly developed bad blocks on their internal storage, so I'm a bit paranoid about that.
Flash memory unfortunately still dies easily depending on the number of write access it gets. And unfortunately an ereader has quite some activity in that regard as it updates its database of books and read progress all the time. With the SD card there is little to no downside (maybe power consumption), you get more storage and its easy to replace. Also it's just nice if I can take the card out, put it in any other device with a card reader (tablet etc) and continue reading there, without having to resync everything. So for you there may be no reason to use it; for me there's no reason not to use it... each to his own |
02-04-2012, 04:17 PM | #10 | |||
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Also: I use an SSD as my Windows system disk. Why? Because it's much faster than a mechanical disk. I'm not concerned about it breaking any more than with a normal disk. Quote:
It's only small chunks of data that is being changed and not very often. Even if it saves every page turn you'd have roughly 100.000 (that's about the number of writes you get out of a single flash cell) times the number of free blocks of memory write accesses. A block is usually 512 bytes. Let's assume you have 100MB free, that's 200.000 blocks. That would make 100.000 * 200.000 = 20 billion write accesses until the memory wears out. Let's say you have 1000 accesses per hour of usage, you'd get 2000 years of usage out of it. And I think 1000 write accesses per hour of reading is quite a lot. So the reading won't be the big factor in wearing the memory. Of course if you constantly add and delete books or run updates or whatever that will eat up a lot of the available write cycles. Again: wear leveling. The real killer for flash is if there's no free space for the wear leveling to use. The fuller your memory is the faster it will degrade. Regards Aydan |
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02-04-2012, 04:39 PM | #11 |
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That's where it doesn't come in, because it's not there. Wear leveling is something that SSD controllers do. It's a technology specific to SSD only. Regular flash media (embedded devices, phones, SD cards, etc.) do not do wear leveling of any kind. Hence you get bad blocks rather quicker than on SSD and if it's in a bad place it might even be an unrecoverable error.
Still it's nothing to worry about, really, as I said: I'm a bit paranoid about it because I had devices fail on me due to bad blocks. Other people spend $5 on a screen protector against scratches they may never get anyway, I spend $5 on an SD card and I'm happy with it, so who cares... |
02-04-2012, 04:52 PM | #12 | |
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I'd say all modern flash devices have a wear leveling capable controller. Be it USB sticks, SD-cards or phones. |
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02-04-2012, 05:15 PM | #13 | |
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Wear leveling actually is quite complicated; each and every (write) access has to be tracked and counted so you have the data necessary to make the descision as to when to make a remap and where to, and your storage solution needs to include a large enough remappable storage reserve. SSDs have this. USB sticks and builtin internal storage on the other hand, is unfortunately only a dumb storage device, so if there's wear leveling, it'd have to be implemented on the OS level. At best you get a filesystem that is able to mark blocks as bad and thus avoid them. That works fine as long as it's not a block the filesystem needs for storing its own metadata, and you end up with corrupted data and lose storage capacity of course. |
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02-04-2012, 05:17 PM | #14 |
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Did you actually read the Wikipedia articles?
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02-04-2012, 05:49 PM | #15 |
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Ok, I stand corrected, to a degree - according to Wikipedia apparently SD cards do have wear leveling (dynamic, shorter life expectancy, but still better than none whatsoever) whereas SSDs do have wear leveling (static, longer life expectancy).
So while SSDs actually do the active tracking and remapping and wear leveling around kind of thing, SD cards apparently have an "empty sector pool" where they grab sectors out of. I also found a document by Sandisk http://www.scribd.com/doc/7010332/SA...-Wear-Leveling where they write that this type of wear leveling works fine for large continuous writes but not all that well for small changes. But then again this document is from 2003 so who knows if it still applies. Even so - any human made storage media fails sooner or later - the SD card is easy to replace, the internal memory is not, so I try to use the SD card. |
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