OESF Portables Forum
Everything Else => General Support and Discussion => Zaurus General Forums => Archived Forums => Accessories => Topic started by: obscurite on October 16, 2004, 08:56:57 pm
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Hadn't heard about a 2GB SD card before but...
I was browsing around my local electronics superstore's site (jandr.com) and I noticed a 2GB Sandisk Ultra 2 Secure Digital card for about $200.00 available for pre-order.
http://www.jr.com/JRProductPage.process?Product=4003911 (http://www.jr.com/JRProductPage.process?Product=4003911)
I feel a lot less jealous of the new SL-C3000 and it's 4GB internal drive now that I can increase my SD storage by A GIG on my C860. Thank goodness my 1GB Kingmax card is "defective" so I can return it and get one of these whenever they're available. I saw it for as low as $181.00 on buy.com
Happy shopping!
-Daniel
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You are not doing to much math on the price difference.
Compare : (SL-C860 + CF/SD 1/2Go) and (SL-C3000 + DD 4Go) in japonese stores or web sites.
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amrein,
Post some prices!!! In US Dollars please
Thanks,
Daniel
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Well, assuming an SL-C860 new from Japan imported would cost $560 (pricejapan.com), $200 added on would bring it up to $760. An SL-C3000 is quoted at $734 after shipping from the same site.
So this is a good solution for someone who already has a C860, but if you're just starting out, it'd be better to go for the C3000.
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Hi ...
Yes on one hand it's nice for people having a c860 (like me *happy with it) ... nice to see those 2 GB SDs in europe (germany) ... maybe in late 2004 ...
on the other hand the new has some nice feates like usb host is the only thing why to buy a sl-c6000 ... but less RAM / FLASH is tooo baaaad ... mechanical 4 GB HDs are bad thing ... better if they use a new 1.8" with 20 or 40 GB ...
Lets see ... waiting for 2005 ... sl-c6xxx ...
Martin
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SD cards tend not to be fast enough for playing video though.
Plus the internal HD of the C3000 can probably be used as swap space without wearing it out (might run the battery down a lot quicker though).
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tumnus,
I haven't tried playing video at all, let alone from SD, but these cards from Sandisk are claiming 9 or 10 MB/s transfer rates. As most movies on the Z will probably be 200MB or less (a guess), I can't see the need to transfer at speed higher than 2-3 MB/s to watch video, so these cards should be fine.
Also, people are always complaining about the alleged limited lifespan of flash storage but I haven't heard a single story yet of an SD or CF card that actually wore out. Anyone have anything more than anecdotal evidence to prove that normal card usage for video/file storage on a PDA can actually wear out one of these cards?
I'm talking about wearing out within say, 5 years (which is way more than most people use a piece of mobile tech gear anyway).
-Daniel
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... these cards from Sandisk are claiming 9 or 10 MB/s transfer rates.
Those rates are for a full SD hardware interface. The Zaurus runs SD cards in MMC compatibility mode and won't see anywhere near those speeds. CF will always be the media of choice on current Zaurus models when speed is a concern.
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fierywater,
Thanks for posting the price info!!
Okay, I agree that starting out with a 4GB disk and a free SD/CF is better for someone buying a first Z. HOWEVER, the C700/C760/C860 have been around for a while, and are WELL SUPPORTED. I imagine that the C3000 will have numerous (although trivial for expert tweakers) issues with running the same things other Z's are running. I could be wrong, but I'm sure everyone here has been burned by being on the cutting edge at some point. Then again, hacking the Z to do all this cool shi^H^Htuff is kind of cutting edge to being with. I wonder how fast the ROM community will embrace the new unit? Perhaps best left for the C3000 threads...
-Daniel
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kopsis,
Wow, thanks for that info. I had no idea that zaurus ran in MMC compat mode. Bummer!
Well, good thing I'm not a video buff
Any idea what the max IO is for MMC compat mode? What kind of speed are we talking here?
-Daniel
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Any idea what the max IO is for MMC compat mode? What kind of speed are we talking here?
Prior to the release of the MMC 4.0 spec in Feb 2004, the theoretical max for an MMC card was 2.6 MB/sec. The newest MMC spec "backports" some of the features in the SD spec to bump that to 52 MB/sec, but that doesn't help current Zaurus models.
In reality, actual throughput on the Zaurus is quite a bit less than the theoretical max. SD benchmarks on the Zaurus that I've seen for various SD cards show read throughput falls between 1300 and 1700 KB/sec. And there's strong anecdotal evidence that performance drops off rapidly when the CPU is busy actually processing the data it's reading.
In writing this reply, I became curious whether I could quantify some of these perceptions. So I built bonnie++ 1.03 (a standard Linux HD benchmark) and tested a 512M PNY SD, 512M SanDisk CF, and 4GB Hitachi microdrive on my SL-C760. Results are as follows (all numbers in KB/sec):
read %CPU write %CPU
PNY 512M SD 1341 66 787 22
Sandisk 512M CF 1819 62 1377 7
Hitachi 4GB CF 1700 34 2008 10
Now, the Sandisk is running pretty close to its max but I've seen the microdrive hit 5000+ KB/sec on a PC, so clearly even the Zaurus CF interface has some inherent throughput limitations. To make things even more interesting, I turned on overclocking and re-ran the two 512MB memory card tests.
read %CPU write %CPU
PNY 512M SD 1320 69 933 4
Sandisk 512M CF 2117 30 1381 6
Notice the small boost in CPU speed makes a big difference in CF read speed but didn't help SD at all. So for the sake of completeness, I repeated the tests one more time with the CPU under a heavy processing load (an endless computation loop) to simulate a task like video processing. When the smoke cleared , I had the following results:
read %CPU write %CPU
PNY 512M SD 750 38 454 12
Sandisk 512M CF 1561 33 1321 6
Hitachi 4GB CF 1569 28 1682 9
Now we're getting the whole picture. Although the crippled SD interface is theoretically a limiting factor, it's actually the PXA255 that is the bottleneck. Not a huge surprise since it's a processor that wasn't really designed to move large amounts of data. SD performance is hurt badly by heavy CPU loads -- much worse than CF. For applications such as video, CF is clearly going to offer the best performance.
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kopsis/Dave,
That was AWESOME. Thanks for the benchmarks for us lazy people who don't check things out for ourselves
I guess the C3000 is more of a blessing than I realized for anyone needing decent IO for video or other applications. Personally, since I don't watch video on my Z, I think a 2GB SD card will serve me well. That said, I can't wait until it's time to upgrade (think about a year or two), at which point I'm sure my new handtop will have lots of storage, wifi, bluetooth and other neat things built in.
Thanks again!
-Daniel
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I should have also mentioned that despite the benchmark results, my 512 MB SD card is still my Zaurus' primary storage and I'll probably be shopping for a 2 GB SD card next spring I keep my microdrive filled with music, movies, and large documents (and the occasional swap file) but the stuff I use daily is on SD. SD may not be the speed king, but that doesn't mean it isn't very usable. And SD doesn't go away when you plug in a wireless card .
I've even gone as far as building the entire Python 2.3 project entirely on the SD card (with the source, intermediate files, and the zgcc tools cramfs image all on the card) and it went surprisingly fast. Linux caching algorithms are top-notch so large block transfer benchmarks, while indicative of multimedia performance, don't necessarily give a good feel for performance of other kinds of applications.
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People here point out at the speed of the mediums but ... mechanical hds are weak .... what if your brand new slc-3000 fall down ? Even taking really care of my 860 it fell down 2 or 3 times with -thank god- no problem... BUT a mechanical hd may get destroyed by falling down and you'll lose everything Besides even moving the hd while reading on it could cause bad sectors or whatever I think i'll stick to my 860 for now
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People here point out at the speed of the mediums but ... mechanical hds are weak .... what if your brand new slc-3000 fall down ? Even taking really care of my 860 it fell down 2 or 3 times with -thank god- no problem... BUT a mechanical hd may get destroyed by falling down and you'll lose everything Besides even moving the hd while reading on it could cause bad sectors or whatever I think i'll stick to my 860 for now
Is not a mini-iPOD or the 500 others mp3 players with 4-5 gigs HD the same thing ? I never heard of the HD stop working so much...
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Solid state cards are more durable than their microdrive cousins, but the microdrives can handle much more abuse than a traditional hard drive (due primarily to the very low mass of the components).
Dropping an operating device with a microdrive is a valid concern and could potentially damage the drive. However just moving a device (even abruptly) with an operating microdrive will not result in any damage or loss of data (unless you move the device by hitting it with a large hammer ). Current microdrives are rated for operating shock of 200G (equivalent to about a 30cm [1 ft]) drop onto a hard surface. When the drive is not actively reading or writing, it spins down and parks - at which point shock tolerance goes up to 2000G (a 3m [10 ft] drop) ... about the same as Sandisk's shock rating for their solid state CF cards.
It is important to keep in mind that *any* storage card in a PDA can suffer catastrophic failure (I have a small box of dead solid-state CF cards so I can say with some confidence that they're not indestructable) and should be backed up on a regular basis!
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The benchmarks for sd speed on oz 3.5.1 seem higher. Anyway, I haven't had any trouble playing video from my sd on either sharp or oz on my 5600 (pxa250). My el cheapo 2.2 gig microdrive is another story entirely.....
ADF
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kopsis, do you still have a binary for the benchmark program? If so, could you send me a copy please? I would like to run some tests of my own to compare sd and high speed sd, and to see if there is any difference if I put the sd card in a cf sd adapter.
If you don't have it could you tell me where and how to get it on my Z please?
What Zaurus did you use to do the tests?
I would like to try and keep my tests as close as possible to yours, so that they can be at least slightly comparable.
Thanks
Simon
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I think this post (https://www.oesf.org/forums/index.php?showtopic=8659&view=findpost&p=53208) will give you most of what you're looking for. Searching the forums for "bonnie" will yield you a reasonably concise list of threads where these benchmarks have been discussed.