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#41
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In article ,
Shailesh Humbad wrote: J. Clarke wrote: David Chien wrote: However, they won't operate for long. They have very limited number of write cycles. Tell that to my 800MB 2.5" flash drive I picked up cheap off ebay.com that's running just fine in my notebook. flash cells typically are rated in the 100,000 cycles per cell lifespan, and with automatic write balancing, drives can last years w/o any problems at all in most user environments. In "most user environments" Windows is constantly updating the swap file, which will kill a flash drive very quickly. If you're not running Windows that's another story but then you're not running anything characteristic of "most user environments". What if we disable the swap file? I wonder if anyone has actually tried running Windows on a flash disk, or if everyone has just been scared off by the write-cycle limitation. I have an extra 256MB flash card, maybe I will try running Win98 off it. A CF to IDE adapter goes for less about $20. WinXP embedded can run from flash disk: http://msdn.microsoft.com/library/de...s/xpehelp/html /xetbsCompactFlash.asp H**l; Winxp/embedded can run in a cell phone! (I think that's what Motorola uses) I know the poeple that write Pebble, a linux tailored to run from a 64 or 128MB CF card on a small mobo that has 64mb RAM. That's all there is. I've built a couple systems from the setup scripts.The Pebble package is a WiFI AP and web server that's widely used for the Free WiFi zones and local coffe shops. Neat stuff. www.nycwireless.com/pebble When Pebble Linux boots it makes some of RAM a memory-resident file system for run-time data. It runs the binaries of the CF card, but this file system is marked RO after booting is complete to protect the life of the CF card. It required some magic to make the Linux kernel happy running from a RO file system. There are MAKERW and MAKERO commands so that I can edit configuration files while the system is running and then make the system disk RO afterwords. Pebble is designed to run for years in remote locations. A couple years ago the guys were conservative about CF card write cycle lifetimes. I haven't heard that they have changed their mind(s). -- Al Dykes ----------- adykes at p a n i x . c o m |
#42
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Al Dykes wrote:
In article , Shailesh Humbad wrote: J. Clarke wrote: David Chien wrote: However, they won't operate for long. They have very limited number of write cycles. Tell that to my 800MB 2.5" flash drive I picked up cheap off ebay.com that's running just fine in my notebook. flash cells typically are rated in the 100,000 cycles per cell lifespan, and with automatic write balancing, drives can last years w/o any problems at all in most user environments. In "most user environments" Windows is constantly updating the swap file, which will kill a flash drive very quickly. If you're not running Windows that's another story but then you're not running anything characteristic of "most user environments". What if we disable the swap file? I wonder if anyone has actually tried running Windows on a flash disk, or if everyone has just been scared off by the write-cycle limitation. I have an extra 256MB flash card, maybe I will try running Win98 off it. A CF to IDE adapter goes for less about $20. WinXP embedded can run from flash disk: http://msdn.microsoft.com/library/de...s/xpehelp/html /xetbsCompactFlash.asp H**l; Winxp/embedded can run in a cell phone! (I think that's what Motorola uses) First, XP Embedded is not quite the same as XP Pro or XP Home. Yes, it can run from a flash disk, or a CD or a ROM for that matter--it purpose to existence in fact is that it can be burned into ROM--but it doesn't give the same functionality. And it's not something that the "average consumer" is going to have or want. Second, the cell phones do not run any flavor of XP, they run a variant the operating system that Microsoft developed to compete with PalmOS, which has gone through so many name changes that I've given up trying to keep track of what they call it this week. I know the poeple that write Pebble, a linux tailored to run from a 64 or 128MB CF card on a small mobo that has 64mb RAM. That's all there is. I've built a couple systems from the setup scripts.The Pebble package is a WiFI AP and web server that's widely used for the Free WiFi zones and local coffe shops. Neat stuff. www.nycwireless.com/pebble When Pebble Linux boots it makes some of RAM a memory-resident file system for run-time data. It runs the binaries of the CF card, but this file system is marked RO after booting is complete to protect the life of the CF card. It required some magic to make the Linux kernel happy running from a RO file system. There are MAKERW and MAKERO commands so that I can edit configuration files while the system is running and then make the system disk RO afterwords. Pebble is designed to run for years in remote locations. A couple years ago the guys were conservative about CF card write cycle lifetimes. I haven't heard that they have changed their mind(s). You can run MS-DOS from a ROM too. It is certainly possible to make a machine that uses a flash disk--Palm and Compaq and many others make such machines and you can buy them at any office supply store. That has never been the issue. The issue was the utility of a $40 IDE flash disk as a replacement for the magnetic disk in a notebook computer used by an "average" consumer. -- --John Reply to jclarke at ae tee tee global dot net (was jclarke at eye bee em dot net) |
#43
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"Shailesh Humbad" wrote in message J. Clarke wrote: David Chien wrote: However, they won't operate for long. They have very limited number of write cycles. Tell that to my 800MB 2.5" flash drive I picked up cheap off ebay.com that's running just fine in my notebook. flash cells typically are rated in the 100,000 cycles per cell lifespan, and with automatic write balancing, drives can last years w/o any problems at all in most user environments. In "most user environments" Windows is constantly updating the swap file, which will kill a flash drive very quickly. If you're not running Windows that's another story but then you're not running anything characteristic of "most user environments". What if we disable the swap file? I wonder if anyone has actually tried running Windows on a flash disk, or if everyone has just been scared off by the write-cycle limitation. I have an extra 256MB flash card, maybe I will try running Win98 off it. A CF to IDE adapter goes for less about $20. Is that a CF to CF-IDE adapter -that merely adds the CompactFlash IDE commandset- that you stick between a CF-card and a CF- slot or a CF to 40 pin IDE connector adapter? Is there any difference in running a flashcard like that and just running a ramdisk on a Flashcard? Aren't there drivers that allow you to run a FlashCard as a disk (emulating the command set)? WinXP embedded can run from flash disk: http://msdn.microsoft.com/library/de...mpactFlash.asp |
#44
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I was looking on froogle and these drives in stores go for upwards of
200? why are they so cheap on ebay He claims they're surplus to a project. Might have "fallen off a truck". works fine for me here. good seller, no problems with the drive. |
#45
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Folkert Rienstra wrote:
"Shailesh Humbad" wrote in message A CF to IDE adapter goes for less about $20. Is that a CF to CF-IDE adapter -that merely adds the CompactFlash IDE commandset- that you stick between a CF-card and a CF- slot or a CF to 40 pin IDE connector adapter? Is there any difference in running a flashcard like that and just running a ramdisk on a Flashcard? Aren't there drivers that allow you to run a FlashCard as a disk (emulating the command set)? AFAIK, you plug the compact flash card into the adapter, and then the adapter into an empty IDE port. I believe the adapter has minimal on-board logic, and is basically just a pass-through. After it's plugged in, it appears to the system just like any other regular hard disk drive. You have to format and partition it, and then the system assigns it a drive letter. No drivers are needed. http://www.acscontrol.com/Index_ACS....CF_Adapter.htm |
#46
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"Shailesh Humbad" wrote in message Folkert Rienstra wrote: "Shailesh Humbad" wrote in message A CF to IDE adapter goes for less about $20. Is that a CF to CF-IDE adapter -that merely adds the CompactFlash IDE commandset- that you stick between a CF-card and a CF- slot or a CF to 40 pin IDE connector adapter? Is there any difference in running a flashcard like that and just running a ramdisk on a Flashcard? Aren't there drivers that allow you to run a FlashCard as a disk (emulating the command set)? AFAIK, you plug the compact flash card into the adapter, and then the adapter into an empty IDE port. I believe the adapter has minimal on-board logic, and is basically just a pass-through. After it's plugged in, it appears to the system just like any other regular hard disk drive. You have to format and partition it, and then the system assigns it a drive letter. No drivers are needed. Which means that there must be some logic that imitates a real IDE bus (which apparently is not all that different from CF in the first place) and IDE command set and registers. http://www.acscontrol.com/Index_ACS....CF_Adapter.htm |
#47
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Eric Gisin wrote:
"P.T. Breuer" wrote in message news or simply drop in a flash hard drive drive. These 2.5" flash drives have 100% no moving parts, and are 100% silent in operation. You can However, they won't operate for long. They have very limited number of write cycles. Nonsense. Flash hard drives are designed for harsh environments, and have ECC and sector remapping just like hard drives. So what? Any flash chip will have in its datasheet the allowable number of rewrites. If you're using it in an environment in which writes are frequent (for example Windows with its page file) then you will use up the allowable writes in a remarkably short time. They can use other tricks like rotating frequently written sectors. Which delay the inevitable. buy them cheap off www.ebay.com (eg. 800MB for ~$40) and they turn any laptop into a silent notebook (assuming CPU fan doesn't make sounds, if Unfortunately, also a dead deadbook, very shortly, if you expect the flash drive to hold up. Flash memory cards have no smarts, yet I don't see them dropping like flies. Flash memory cards are not normally used as primary storage. -- --John Reply to jclarke at ae tee tee global dot net (was jclarke at eye bee em dot net) |
#48
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"J. Clarke" wrote in message ... Eric Gisin wrote: Nonsense. Flash hard drives are designed for harsh environments, and have ECC and sector remapping just like hard drives. So what? Any flash chip will have in its datasheet the allowable number of rewrites. If you're using it in an environment in which writes are frequent (for example Windows with its page file) then you will use up the allowable writes in a remarkably short time. Then you detect the error and remap the bad sector. Sound familiar? They can use other tricks like rotating frequently written sectors. Which delay the inevitable. Nope. You have millions of sectors, some of them spares. Flash memory cards have no smarts, yet I don't see them dropping like flies. Flash memory cards are not normally used as primary storage. They all have frequently written areas, the FAT and root dir. Why aren't they dying? |
#49
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Eric Gisin wrote:
"J. Clarke" wrote in message ... Eric Gisin wrote: Nonsense. Flash hard drives are designed for harsh environments, and have ECC and sector remapping just like hard drives. So what? Any flash chip will have in its datasheet the allowable number of rewrites. If you're using it in an environment in which writes are frequent (for example Windows with its page file) then you will use up the allowable writes in a remarkably short time. Then you detect the error and remap the bad sector. Sound familiar? They can use other tricks like rotating frequently written sectors. Which delay the inevitable. Nope. You have millions of sectors, some of them spares. Flash memory cards have no smarts, yet I don't see them dropping like flies. Flash memory cards are not normally used as primary storage. They all have frequently written areas, the FAT and root dir. Why aren't they dying? Hello, Eric: "Flash memory cards" will wear out, physically, after a comparatively brief number of write cycles (100,000 is typical). Are "flash hard drives" any more durable? Cordially, John Turco |
#50
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"John Turco" wrote in message
... Eric Gisin wrote: "J. Clarke" wrote in message ... Eric Gisin wrote: Nonsense. Flash hard drives are designed for harsh environments, and have ECC and sector remapping just like hard drives. So what? Any flash chip will have in its datasheet the allowable number of rewrites. If you're using it in an environment in which writes are frequent (for example Windows with its page file) then you will use up the allowable writes in a remarkably short time. Then you detect the error and remap the bad sector. Sound familiar? They can use other tricks like rotating frequently written sectors. Which delay the inevitable. Nope. You have millions of sectors, some of them spares. Flash memory cards have no smarts, yet I don't see them dropping like flies. Flash memory cards are not normally used as primary storage. They all have frequently written areas, the FAT and root dir. Why aren't they dying? "Flash memory cards" will wear out, physically, after a comparatively brief number of write cycles (100,000 is typical). Are "flash hard drives" any more durable? I already answered that. Twice. Learn to read. |
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