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iPod Shuffle RAID
ricercar writes "So, what do you do when you and some friends are all getting iPod Shuffles? You make a RAID array out of them, of course! The original intent was to actually install OS X on the RAID and boot from that, but the OS X (Panther, 10.3.5) Installer wouldn't allow it."
Uh, hard-drives actually have faster transfer rates than most flash memory.
This and other hacks can be found at hackaday.com
"If it has screws, it was meant to be taken apart."
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I tried this a number of years ago. In fact, there's an CF->IDE interface board that is very inexpensive that I purchased. Turned out that CF was much slower than my hard drive.
Might be interesting to try it again with today's professional flash memory, but with readily available CF memory from about 3 years ago, I was able to install a Windows OS on it but it was slower than my hard drive.
If you really want something like this, there are memory drives that use actual battery-backed up RAM (take your pick of varities) that are as you would expect lightning quick. Last I checked though Bitmicro's Site, they were very expensive.
I'm a big tall mofo.
most CF cards don't do DMA. That's part of the speed problem right there. Also flash is fast to seek, but slow to stream reads and really slow to stream writes.
Some of the newer cards do support better transfer modes. These are usually cards marked as 44x or 40x or whatever CF. And they usually cost $10 more.
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tiny IDE/CF interface recommended (and sold) by DSL
Stop Computers/Cars Analogies on S
Like here?
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They just need to follow this hint
Most NOR-flash is rated for at least 100,000 erase cycles. And some of the newer AMD flash devices have a minimum 1,000,000 erase cycle guarantee per sector. Even erasing the entire flash 100 times a day would give you about 27 years of life.
I don't think Macs can boot off of USB 2.0. That would be one reason.
I understand Apple went with USB 2.0 to cater to the PC crowd, but making the drive firewire would have been revolutionary.
The Kangaru Fire flash drives KILL USB 2.0 in transfer speeds and CAN boot a Mac OR a PC.
A raid would have been possible otherwise.
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http://mirrordot.org/stories/b810b5b7bf18eb8d82adf 1137dae0587/index.html
Assuming you have some Xsan licenses lying around (you bought Xsan or are part of the seed program), you can install Xsan http://apple.com/xsan on your shuffle. You need to initialize the shuffle as being one big free space partition using disk utility, then use Xsan Admin to label the shuffle as a LUN.
;-)
Instant iPod Shufle SAN. Of course, only one machine can access it... and it is really slow. Throw in a powered USB hub and some more shuffles and you may be able to get a few meg a second.
Take that floppy disk RAID!
Word to the wise: running your iPod drive that hot, that frequently causes your battery to lose its longevity pretty severely. I regret having done it last year.
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Ha ha! No, seriously, I (almost) feel your pain. I was in the same boat 24 hours ago. Had my mind made up I was getting the wife a 1 GB shuffle for V-day. Knew I'd waited way too long, as the initial buying rush had sucked up every shuffle in the known universe.
:)
But this was one time I'm actually glad I live in the hellhole called southern California. 9 Apple Stores within an hour's drive, and 2 more within 100 miles. I started calling them one by one... "No, we're all out and we don't know when we'll get more in. We're not doing a waiting list because the supply is so scarce." Ditto. Ditto, ditto, "we have 512 MB but not 1 GB," ditto. Then the glorious answer I was waiting for... "We have both in stock. We'll hold one for you for 2 hours." Yes!!
It took me damn near 2 hours to fight traffic and get down there, but I got it. None on the shelves, but mine (er, my wife's) was waiting in the back for me. Thank you Apple Store South Coast Plaza!
So, like, if you have a lot of Apple Stores around you, keep calling. Or call other stores - I heard CompUSA has had some briefly, maybe Micro Center, Best Buy, etc. You never know!
Um, actually you don't. Linear flash went out of style years ago, as any Newton owner can tell you. With the exception of flash cards for older Cisco gear, all flash cards these days use an ATA interface. Anything that uses a non-PCMCIA slot (CF, MMC, SD, XD, SonyStick) is 100% ATA.
--
"Open source is good." - Steve Jobs
"Open source is evil." - Microsoft
Crappy terrorist plans, at that. If lose two drives, the remaining data doesn't magically *poof* out of existence. You'll certainly lose information, but a lot can be learned from the rest. There are real cryptosystems for requiring N out of M keys to be present for information to be recovered. This is not one of them.
This is just confusion caused by the x86-centric world's definition of "DMA".
NAND flash natively cannot be randomally accessed like ordinaly memory. It's treated more like a hard drive - you read entire sectors at a time (528 byte in this case), and erase/rewrite entire pages at a time (128KB for type II).
On the other hand, NOR flash is designed to be randomly readable like ordinary external memory, but writes still require an entire page erase/rewrite. But NOR is typically only used for boot ROMs in PCs and some embedded devices. They're small - up to about 4MB, whereas NAND flash is anything up to 512MB in a single chip. Any CF FLASH card you buy will be NAND (or MLC, which is similar) based.
CF cards supposedly don't have "DMA" because they don't support IDE DMA or UDMA modes. That limits them to PIO modes, which maxes at around 16MB/sec. For some hair brained reason, the x86 IDE interface infers this as meaning that the CPU must also access in PIO mode, and doesn't provide a DMA interface from the CF to memory, which is another speed impact. On most modern embedded devices I've used, even if the CF card doesn't support DMA, you are still presented with a DMA interface to access the card in PIO mode! It's just x86 which does it wrong.
In fact, CF can support DMA. You get DMA support on some of the 4GB/5GB hard CF type II hard disks - it's just not standardised (or documented...)