FLASH market collapses

That reminds me. Does anyone know of a suitable way to patch the internal drive descriptor for thumb drives to make them appear as non-removable devices to the OS? The motivation is that on a Windows box they can then be configured as a RAID array (which for some random lookup table intensive problems would be an advantage). It is assumed they would be locked in place to avoid user interference.

Regards, Martin Brown

** Posted from **

Compact Flash was an earlier technology. Early adopters of digital still have a fair investment in both CF flash drives and IBM microdrives. There is a fairly complex controller in them. And the connector technology is vulnerable to bending delicate pins inside the kit.

SD cards by comparison are pretty dumb and cheaper, smaller to make. Also the connectors are more difficult for the ham fisted to permanently damage (although getting finger grease on them is easy enough).

Biggest problem is that as memory sizes increase so does current consumption and the amount of data you could lose if things go pear shaped. Some older gear may find it hard to cope with devices that cross certain magic boundary lines too - eg 32 bit addressability.

But I have had my Pentax istD camera (original firmware) play up with a

2GB card. Easily fixed, but the failure mode was extremely annoying - flashes message up on rear view screen on an SLR and continues to "work" as normal but no more images are saved.

Regards, Martin Brown

** Posted from **

On a sunny day (Tue, 22 Jul 2008 17:10:04 -0500) it happened "Tim Williams" wrote in :

That is easily tested: Lets grab Andromeda I recorded from ITV4 last night, it is a digital TV transport stream, not modified in any way. I will put it from the main PC into a 4GB USB flash. We do this the Linux way, FYI: Insert USB stick, test if detected: dmesg sda: assuming drive cache: write through sda: sda1 sd 0:0:0:0: Attached scsi removable disk sda

OK, detected, let's mount it: mount /dev/sda1 /mnt/sda1 Copy 100MB of Andromeda for test: dd if=andromeda_x.ts of=/mnt/sda1/test.ts bs=1000000 count=100 Type 'sync' to actually flush it to the USB stick (else it stays in RAM). sync This takes a while, flash write is slow...

Unmount the stick: umount /dev/sda1 Now let's take the USB stick to an other PC, my eeePC, so I can watch Andromeda on the train:

Start eeePC Open a terminal window with ctrl alt T. become root sudo su - Insert USB stick. Ignore stupid pop up of auto mount that does not work anyways, mount by hand: mount /dev/sdc1 /mnt/sdc1 (yes disk numbering is different here) Logout as root ctrl D Now here we go: mplayer -vf scale=1200:960 -fs -vop pp=0x20000 -monitoraspect 800:480 -cache

8192 /mnt/sdc1/test.ts Of course I already had most of this scripted, not sure you need the 'scale', the large cache helps to play fluently. The '-vop' forces de-interlace, the '-monitoraspect' fits it to the wide screen eeePC display. The '-fs' means full screen.

The answer to your question is YES, even on a low power low speed processor device as the eeePC. Plays with no irregularities, sound also OK (is mp2 encoded on sat), aspect OK, everything fine. Picture is mpeg2 encoded and yes the eeePC uses hardware acceleration in decoding it (top shows hardly any CPU use). And this was the cheapo 4GB USB stick.

It also shows how that eeePC can be a great movie player for for example kids in the back of the car. Much more versatile then those (just as expensive) portable DVD players, you just copy the DVD to the USB stick on the main PC. So what I am saying is: Perhaps the time of the rotating media (disks) has come to an end...

In case that is .dv, then yes the stream is made up of a series of .jpeg pictures, and used much more bandwidth. You have to re-code it to H264 perhaps (or mpeg2). My digital camera records directly into mpeg4 on SDcard, and plays no problem.

More times, yes.

Oh, it saves as .AVI, but some bigass mostly-uncompressed thing. A typical minute is, well let's see... 38MB for 56 seconds in one case. Just about

40MB/min, which is, well that's around 0.67 MB/s, which is more than enough for USB to sink, even crappy USB (probably like I have, or cheap thumbdrives would use..). But then, it occurs to me that AVI isn't a streaming format, which might be why it's misbehaving. But then but then, it should still be able to load the whole thing in a few seconds, even while it's playing, even if AVI isn't streaming. So I don't get it.

Hmm, I'd make reference to the PNY card reader I have ... but it doesn't exist. Long ago superseded I'm sure. It has a transparent purple front bezel and beige plastic case, in case that sounds familiar.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

On a sunny day (Wed, 23 Jul 2008 11:24:52 -0500) it happened "Tim Williams" wrote in :

AVI is a 'container' format, it can contain many things (formats).

There is however USB1 and USB2, USB2 is faster, no tsure if USB1 can do 670kbps.

This is what I get for USB1 with the 4GB stick: grml: ~ # hdparm -t /dev/sda1 /dev/sda1: Timing buffered disk reads: 4 MB in 4.51 seconds = 907.28 kB/sec

This is what I get when connected to USB2 (same USB stick): eeepc-unknown:/root> ./hdparm -t /dev/sdc1 /dev/sdc1: Timing buffered disk reads: 82 MB in 3.02 seconds = 27.18 MB/sec As you can see there is a _HUGE_ difference in speed.

( The avid reader and eeePC owner will notice there is no hdparm on the eeePC, well you can find all those magical binaries here: ftp://panteltje.com/pub/eeepc/ )

Maybe you have an old PC with USB1, or an old card reader with USB1 support only, or both?

Does anyone do a SATA connector/adapter for a pile of SDs etc to turn them into a cheap SSD? The latter are way overpriced.

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
Remote Viewing classes in London

ott

20Euro,

ry,

new

ice.

Negative feedback? Is that another word for "DRAM price fixing"? :-)

Not SD cards (that I'm aware of), but compact flash (CF) cards have a regular old IDE interface and just need a different connector to directly plug into a PATA adapter (such things can be found on eBay for PATA adapter boards, if you really wanted to.

Note that "real" SSDs are not as overpriced as you may think: While there certainly is some extra cost meant to recoup R&D (the "early adopter" penalty), a good SSD often has considerably better read/write speeds and often better endurance than most CF/USB/SD cards.

Folks like Lenovo and Apple are really pushing the SSD idea, so you can bet that with the millions of units per year they're buying, they're exerting as much pressure as they can to get the pricepoints to be more competitive with rotating media.

---Joel

I would like to use a SSD in place of a HDD in a RAID server to hold the OS. Only need 32MB. That would be about $128 of USB flash.

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
Remote Viewing classes in London

You probably mean 32GB?

Definitely doable. I setup a machine that gets knocked around a lot (hard drive had been damaged previously) with Windows XP on a 32GB CF card for a total cost of

Windows keeps telling me I can "run this device faster with USB 2.0", but it neglects to tell me where that port happens to be installed. ;o( Motherboard manual says 4 x USB 1.1 ports, which Google suggests goes up to

12Mb/s, which should seem like just enough (yeah, in theory..).

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

Not entirely, as flash is still at least an order of magnitude slower than the main system memory.

You're right about the swap file, though -- people do debate it a lot, although I've seen a few calculations where making "reasonable" assumptions the expected life was still much better than a decade, by which point the machine will be woefully obsolete anyway. Hence, I kept the swap file around... and don't expect it to be used much, as the machine has 2GB of RAM.

Like regular hard drives, AIUI flash drives also have a certain number of spare sectors that get used up as the "regular" sectors die. Conceivably, if the flash drive exhausted those if could start using unused "regular" sectors and marking them "bad" in the file system's map of used/free/bad sectors, but I doubt if that's currently practical since the flash drive would have to know what file system was in use to pull this off (or have a protocol to tell the file system driver what was going on.

It's not pretty when regular hard drives run out of spare sectors: You can usually still read from the drive, but the moment you try to write the drive usually hangs and often the operating system crashes shortly thereafter.

---Joel

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
Remote Viewing classes in London

It's even more sophisticated than that, in most of the flash drives used today (e.g. drives connected via USB, SCSI, or ATA).

The drives do have a substantial number of spare sectors, and their on-board controller implements sophisticated block-remapping and "wear levelling" algorithms. Any given sector (from the host's point of view) is likely to be written to a different spot in the flash every time it's written... the on-board controller writes the data to an unused (and pre-erased) block in the flash, and then updates its internal "map" which gives the "logical sector number to actual flash position" correspondence.

The mapping and wear-levelling is efficient enough that the flash's life tends to be proportional to the *total* number of sectors written to the drive over time, and is rather independent of *which* logical sectors you're writing. Writing 10,000 different sectors, one time each, actually puts just about the same amount of wear-life on the flash as writing a single sector 10,000 times.

In effect, the whole flash tends to wear out almost simulaneously, as every block in the internal flash chip reaches its write-cycle limit.

And, yes, the controllers do detect and then avoid (spare out) bad sectors in the flash. NAND-flash chips *all* come from the factory with some bad blocks... it's inevitable. The controllers find these during the initial formatting and eliminate them from the wear-levelled block rotation.

Neither the initial "sparing out", nor the wear levelling, nor the automatic replacement of "grown" defective blocks with good ones, requires fiddling around with the operating system's filesystem structures at all. As far as the OS is concerned, the flash device is "perfect" - no bad blocks. The defect and wear management is being performed "below the waterline" and the OS is unaware that it is taking place.

--
Dave Platt                                    AE6EO
Friends of Jade Warrior home page:  http://www.radagast.org/jade-warrior
  I do _not_ wish to receive unsolicited commercial email, and I will
     boycott any company which has the gall to send me such ads!

Not so at all. The embedded market uses them for disk drives.

On a sunny day (Wed, 23 Jul 2008 19:37:16 -0500) it happened "Tim Williams" wrote in :

I think I have once seen USB2 PCI plugin boards for sale, but that was many years ago. These days a new motherboard with embedded graphics, and H264 hardware acceleration, need not be that expensive, less then 80$ (estimate). Add a processor, for video 1GHz is already plenty (my experience with Linux), unless you want to do high resolution, then you need a dual core 3.5GHz perhaps. Perhaps a new power supply, for less then 500$ one should be able to put together a new box that is 'state of the art'. Of course MS Window users may need to buy a new OS as well, maybe yet an other reason to go Linux.

Or just live with the USB1, and compress your movies to mpeg2 or H264, or wmv? Does not MS windows come with a a program for that? Linux users can use ffmpeg and or mjpegtools.

Ya, technically I need a new motherboard *anyway*. USB 1.1 is just more proof that I do. :^)

As is, this thing runs Windows XP SP2 at 1600x1200 just fine, and I was just playing Doom 3 comfortably at 1024x768. I suspect Doom bogs down more for processor-intensive things (like monsters and lots of lights) than for the most complex scenes; my video card is painfully newer than the mobo is!

Probably. I use something else, which lets me "crop" too, and some other stuff I haven't the least clue how to use (evidently *nobody* makes a usable video editor, so I guess I shouldn't be surprised how useless this one is). I find WMVs compress the best for a given quality; that same clip I mentioned (1 minute) goes down to < 5MB with noticable degredation in picture quality.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms