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Author Topic: Backup Stuff
magefile
Highlie
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Icon 1 posted May 02, 2006 23:48      Profile for magefile     Send New Private Message       Edit/Delete Post   Reply With Quote 
So I have a USB hard drive that holds about 35 gigs. If I format it with HFS+, will I be able to read it on a machine running Windows XP? What about the "Unix File System" in Disk Utility (and *which* Unix fs is that, anyway?)?

Part two: if I have a rar file that's about 30 gb on said drive, is there any way to unzip it or otherwise check its integrity on the same drive? The decompressed size is about 32 gb, so it would fit by itself; I just don't have room for both the compressed and decompressed versions.

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Let them be stupid - the market will sort it out.

Posts: 743 | From: Massachusetts | Registered: Aug 2004  |  IP: Logged
GameMaster
BlabberMouth, a Blabber Odyssey
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Icon 1 posted May 03, 2006 03:30      Profile for GameMaster   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
Windows doesn't support HFS+, ext2 or ext3. You may be able to get 3rd party tools to read it, but the OS it's self doesn't.

Moreover, Flash has write limitations (after 10,000 flashes (that is times being erased)). It eventually becomes readonly. I don't know HFS+, but ext2 and ext3 use built in optimizations for writing to the hard disk and journaling... These optimizations make erases more common.

FAT12 or FAT32 is probably the best format for flash interopability and slowing the failure rate of the drive. Moreover, ext2 and ext3 (and I'd imagine HFS+) have permission bits which depend on the system the files are writen with -- moving it from system to system to another may create permission problems (or at least I'd imagine).

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Posts: 3038 | From: State of insanity | Registered: Mar 2002  |  IP: Logged
The Famous Druid

Gold Hearted SuperFan!
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Icon 1 posted May 03, 2006 04:34      Profile for The Famous Druid     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by magefile:
So I have a USB hard drive that holds about 35 gigs. If I format it with HFS+, will I be able to read it on a machine running Windows XP? What about the "Unix File System" in Disk Utility (and *which* Unix fs is that, anyway?)?

No, windoze won't read any of the above without help. I've heard about utilities to read 'foreign' file systems, but haven't used them m'self.

If you format as one of the FAT filesystems as GM suggests, OS X should be able to read/write it, but the maximum file size for the FAT systems is 4 Gig (minus one byte for the pedants) so you wouldn't be able to put your ginormous rar file on it.


Part two: if I have a rar file that's about 30 gb on said drive, is there any way to unzip it or otherwise check its integrity on the same drive? The decompressed size is about 32 gb, so it would fit by itself; I just don't have room for both the compressed and decompressed versions.

Most of the archivers have a command to 'verify' an archive (on 7-zip it's File->Test Archive). Typically these will go through the archive performing a CRC check on all the files, this'll detect most problems, but it's not unknown for an archive to pass these tests and still fail to do a real decompress.

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If you watch 'The History Of NASA' backwards, it's about a space agency that has no manned spaceflight capability, then does low-orbit flights, then lands on the Moon.

Posts: 10669 | From: Melbourne, Australia | Registered: Oct 2002  |  IP: Logged
ChildeRoland
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Icon 1 posted May 03, 2006 05:22      Profile for ChildeRoland     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by GameMaster:
Windows doesn't support HFS+, ext2 or ext3. You may be able to get 3rd party tools to read it, but the OS it's self doesn't.

Moreover, Flash has write limitations (after 10,000 flashes (that is times being erased)). It eventually becomes readonly. I don't know HFS+, but ext2 and ext3 use built in optimizations for writing to the hard disk and journaling... These optimizations make erases more common.

FAT12 or FAT32 is probably the best format for flash interopability and slowing the failure rate of the drive. Moreover, ext2 and ext3 (and I'd imagine HFS+) have permission bits which depend on the system the files are writen with -- moving it from system to system to another may create permission problems (or at least I'd imagine).

Where did this discussion of Flash drives come from?

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Childe Roland

Posts: 311 | Registered: Apr 2005  |  IP: Logged
magefile
Highlie
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Icon 1 posted May 03, 2006 05:51      Profile for magefile     Send New Private Message       Edit/Delete Post   Reply With Quote 
Thanks, guys. It isn't a flash drive, by the way - just a USB enclosure.

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Let them be stupid - the market will sort it out.

Posts: 743 | From: Massachusetts | Registered: Aug 2004  |  IP: Logged
csk

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Icon 1 posted May 03, 2006 06:03      Profile for csk     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by The Famous Druid:
If you format as one of the FAT filesystems as GM suggests, OS X should be able to read/write it, but the maximum file size for the FAT systems is 4 Gig (minus one byte for the pedants) so you wouldn't be able to put your ginormous rar file on it.

Actually, you should be able to create a fat filesystem to fill the whole disk, as long as you use FAT32 or whichever the most advanced FAT is. There is however a limit to how big a FAT filesystem most Windows variants will let you format (32G from memory), but it will quite happily interact with one that big as long as something else has formatted it.

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Posts: 4455 | From: Sydney, Australia | Registered: Jan 2003  |  IP: Logged
dragonman97

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Icon 1 posted May 03, 2006 06:25      Profile for dragonman97   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by csk:
quote:
Originally posted by The Famous Druid:
If you format as one of the FAT filesystems as GM suggests, OS X should be able to read/write it, but the maximum file size for the FAT systems is 4 Gig (minus one byte for the pedants) so you wouldn't be able to put your ginormous rar file on it.

Actually, you should be able to create a fat filesystem to fill the whole disk, as long as you use FAT32 or whichever the most advanced FAT is. There is however a limit to how big a FAT filesystem most Windows variants will let you format (32G from memory), but it will quite happily interact with one that big as long as something else has formatted it.
Weird aside: I've found many USB hard drives that seem to ship with FAT32 that are much larger than the normal limit of FAT32...even though XP will not allow you to format a drive this big. What's up with that? More to the point, can I trust it to be correctly formatted and to operate correctly. Common practice dictates one should reformat a disk when they first receive it, to be very sure it's good - in this case, it would render it less usable (you'd have to partition it).

Also, I'd add that recent comments on /. suggest that modern flash devices can be written to many more times than in the past (>100k, if not 1M times) - and that's per sector/logical division. It's been suggested that the flash drives' controllers may have the intelligence to balance usage, to prevent areas from 'dying' prematurely.

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There are three things you can be sure of in life: Death, taxes, and reading about fake illnesses online...

Posts: 9331 | From: Westchester County, New York | Registered: May 2001  |  IP: Logged
MacManKrisK

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Icon 1 posted May 03, 2006 06:46      Profile for MacManKrisK     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
Originally posted by csk:
There is however a limit to how big a FAT filesystem most Windows variants will let you format (32G from memory), but it will quite happily interact with one that big as long as something else has formatted it.

If you have access to a Win98 machine, Win98's fdisk (in "large disk mode") can make a FAT32 partition up to 127G.

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"Buy low, sell high
get rich and you still die"


Posts: 2331 | From: Southwest Michigan, USA | Registered: Oct 2001  |  IP: Logged
The Famous Druid

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Icon 1 posted May 03, 2006 13:53      Profile for The Famous Druid     Send New Private Message       Edit/Delete Post   Reply With Quote 
Please note that my previous posting gave the maximum file size not the maximum partition size.
The maximum file size is 4 G (minus 1 byte) on FAT32 and FAT16, while magefile needs to put a 30G file on his drive, so none of the FAT filesystems will work for him.

btw - why all this talk about flash? Magefile talks about a 32G USB drive, no mention of flash anywhere, and while flash keys are getting bigger, I haven't seen any 32G ones yet.

btw2 - the disk size of 32 G makes me suspicious, that's the official maximum partition size for FAT32. Could it be that you have a 200 G drive that's just had a single FAT32 partition put on it? Worth checking.

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If you watch 'The History Of NASA' backwards, it's about a space agency that has no manned spaceflight capability, then does low-orbit flights, then lands on the Moon.

Posts: 10669 | From: Melbourne, Australia | Registered: Oct 2002  |  IP: Logged


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