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Motion LS800 table HD failure at 14,000 feet
In rec.aviation.misc Peter wrote:
Flash alternatives (I believe it is a 1.8" HD inside) are extremely costly, around USD 2000 for 8GB, and I wonder how successful it would be to put in a 4GB SD card (for which there is a slot), put all maps on that, etc. I recently did something like this at work, for somewhat the same reason. In my case, I had a couple of accelerometers connected to a data acquisition card in an old desktop PC. The accelerometers got bolted into a car that was going to be crash-tested, and the PC got to go along for the ride. We decided that a rotating-platter drive probably wouldn't cut it, and looked for alternatives. What we ended up using was an "IDE 4000" series flash drive from M-Systems. This is flash memory in a package with an IDE connector; it looks and works just like a regular hard drive to the operating system. M-Systems sells a couple of different lines of drives - the ones that support the latest and fastest interfaces (Ultra ATA and SATA) are indeed expensive - about US$850-$900 for 2 GB. The IDE 4000 series is not quite as fast but is much cheaper; around $200- $250 for 2 GB in a 3.5" drive. We bought a 2 GB drive from Digi-Key, http://www.digi-key.com/ - current catalog page http://dkc3.digikey.com/PDF/T063/0865.pdf . This system was so old that it was running Windows 98. With the regular hard drive still in the system, I uninstalled all unneeded programs and got the total installed size of the system down to well under 1 GB. I then installed the flash drive and did a drive image copy from the hard drive to the flash drive (think Norton Ghost or similar). Then I removed the hard drive and let the system boot up on the flash drive... no problem. Benchmarking programs showed that the flash drive was indeed slower than the hard drive, but neither Windows nor the data-acquisition software seemed to care - I could still log data to the flash drive as fast as I needed to. The computer and the flash drive survived the wreck and everyone was happy. The problem is that Windoze itself accesses various bits of the HD anyway, and does anyone know which bits, and can they be moved to the SD card? Microsoft knows but they ain't tellin'. I think it's possible to split things up like this, but it will take a lot of trial and error to make sure you've got everything you need on the SD card. Even then, if you accidentally click on the wrong icon or something, Windows may still try to spin up the hard drive. If you have a real Windows installation CD (not a "restore" CD provided by the computer manufacturer), it might be interesting to remove the hard drive from the PC, install the SD card, boot up the Windows install CD, and see if you can convince it to install onto the SD card instead. If that doesn't work, then buying a flash drive that has an IDE interface, installing it along with your current hard drive, and doing a disk copy from your current drive to the flash drive (assuming you can fit everything onto the flash drive) will probably work. If there aren't enough hard drive connections on your portable PC, you may have to temporarily install both drives on a desktop PC to do the drive copy, then put the flash drive back in the portable. I hope this helps! Matt Roberds |
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Motion LS800 table HD failure at 14,000 feet
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Motion LS800 table HD failure at 14,000 feet
In rec.aviation.misc Peter wrote:
I need at least 8GB and in 1.8" format, and it doesn't seem to be available. I think M-Systems has flash disks in 1.8", but Digi-Key doesn't carry that line. I don't know how much storage they offer in 1.8". An alternative might be to buy a 2.5" or 3.5" IDE flash disk and put it in an external USB enclosure. This will probably work a lot better if your portable PC has USB 2.0 ports and you use a USB 2.0 enclosure. The other thing is that the BIOS doesn't support the SD slot as a bootable block device, so one couldn't (AFAIK) install windoze on the SD card directly. You might have to install it somewhere else, image it over to the SD card, and then use something like Smart Boot Manager http://btmgr.sourceforge.net/about.html to boot from the SD card. I've used SBM on a floppy to boot various installation CDs on an older PC that didn't have a BIOS setting for booting from CD. Of course your PC probably doesn't have a floppy, so you'll have to be creative. I am just curious what "altitude" solutions the GA vendors are offering... they can't all pack up at 14k, or can they???? I can think of a few reasons this wouldn't work, like condensation, poking holes in it with the stylus, and dying of embarrasment if anyone sees it, but how about a big Ziploc-type plastic bag? Wait until 10000 or so, put the PC in the bag, seal it up, and the PC has a nice little pressurized compartment to live in. OK, having a bag failure take out all of your navigation information probably isn't the best idea. Maybe put a normal hard drive in a USB enclosure, then put the USB enclosure in a Pelican case or similar and figure out a way to seal around the cable. Matt Roberds |
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Motion LS800 table HD failure at 14,000 feet
Peter wrote:
snip Yesterday I got another copy of the U.S. Flying magazine through my door and looking through it I see loads of vendors selling aviation related software products (Anywheremap etc etc) on the ls800. I just cannot believe that this issue has not come up before. It is as if nobody in the USA flies unpressurised above 14k feet, which I am sure has to be rubbish. The reason more EFBs don't support a flash drive is that merely replacing the hard drive with a big flash drive is not the proper solution. The problem is compounded by the fact that most EFB vendors are not embedded systems engineers. They simply want to treat the EFB platform as a standard PC on which they install the OS (Windows), their application software (flight planner, etc), and be done with it. If you want a reliable EFB solution, that is clearly not the answer. The problem is flash memory excels only as a read-only medium due to its write cycle limitations (both in terms of speed and number of cycles). If you're updating your application data on the flash every 28 days (or even once a week), that's no problem, but if you install the OS such that it operates directly from the flash drive, the constant writes to the swap file and other meta data will kill the flash in short order. The benefits and limitations of flash memory are nicely outlined he http://en.wikipedia.org/wiki/Flash_memory In order for a flash drive to effectively replace a hard drive in this application, you have to do some engineering to load an OS image from flash and execute it entirely in ram. AFAIK, Windows (the consumer version at least) cannot do this. -Doug -------------------- Doug Vetter, ATP/CFI http://www.dvatp.com -------------------- |
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Motion LS800 table HD failure at 14,000 feet
"Peter" wrote in message ...
.... but it is a consequence of the lousy windoze memory management: no matter how much RAM you give it, it still uses the swapfile. The vintage Win3.1 didn't do this but everything since has done. Samsung have just announced a range of laptops which will use flash drives, and they are running standard windoze XP. I don't know what they do about the swapfile... Did you intend to say that WinXP cannot run without a paging file? That's would be incorrect, of course. |
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