Windows Phone 7 - The filesystem and how it is presented to the user

Da_G

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Aug 20, 2007
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Windows Phone 7 represents a radical leap in the way the filesystem is presented to the user compared to WinMo. No longer will the user be able to access the true, underlying filesystem in any direct way - the OS will abstract the file system to a single view of all files - making no distinction between files stored on internal flash, or removable storage, or even striped across both similar to RAID0. The file system functions as a Virtual Unified Storage system.

WP7 will support SD cards, but the functionality is different now. The user data is striped across the SD card and the internal storage. This results in functionality similar to RAID0 - if a member disk is pulled from the set, the entire set ceases to function. Similarly, in WP7, if an SD card is pulled from a deployed device, the device will go into a "reduced functionality" mode - where you are only able to make emergency calls. Upon re-inserting the SD, the data is restored and the system functions normally as it would before the card was pulled. If the card or its data is not available (got corrupted, lost, eaten) - The phone must be "hard reset" to restore full functionality and all user data will be lost.

My guess is this was at least partly done as a method to lock down the security of marketplace apps.
 

l3v5y

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I can see some advantages in this, in that it doesn't matter to a user whether it's on the memory card or on device, but will this completely screw up using the device as a USB storage device?
 

TaurusBullba

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Thanks for the info! Would this have similar benefits of raid0 (increased performance w/sd card)? I guess if you want to upgrade your card it sounds like you'll have to give it a hard reset. That sounds like it could be a bit of an issue for many users. I wonder if, while it may allow support for an sd card, they may eventually only support non-removable cards because of that?
 

timmymarsh

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Makes me wonder why bother then? We all know that sd/micro/minis have a tendancy to corrupt after a year or so (depending on use) so surely its bloody pointless??

Just rely on the internal storage like iphone etc.
 

TehPenguin

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Makes me wonder why bother then? We all know that sd/micro/minis have a tendancy to corrupt after a year or so (depending on use) so surely its bloody pointless??

Just rely on the internal storage like iphone etc.
I'd rather have it user removable such that it can be upgraded\expanded.

Also, if the card isn't constantly removed\inserted and is of a decent quality, then it'll probably last the life of the phone.
 

vangrieg

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Makes me wonder why bother then? We all know that sd/micro/minis have a tendancy to corrupt after a year or so (depending on use) so surely its bloody pointless??
I think that this is just a new requirement, and OEMs had been developing devices with SD cards, so it accomodates this fact.
 

adamw79

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Mar 2, 2009
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Removable storage??

What do you mean removable storage? Last I heard it was all non removable?
Windows Phone 7 represents a radical leap in the way the filesystem is presented to the user compared to WinMo. No longer will the user be able to access the true, underlying filesystem in any direct way - the OS will abstract the file system to a single view of all files - making no distinction between files stored on internal flash, or removable storage, or even striped across both similar to RAID0. The file system functions as a Virtual Unified Storage system.

WP7 will support SD cards, but the functionality is different now. The user data is striped across the SD card and the internal storage. This results in functionality similar to RAID0 - if a member disk is pulled from the set, the entire set ceases to function. Similarly, in WP7, if an SD card is pulled from a deployed device, the device will go into a "reduced functionality" mode - where you are only able to make emergency calls. Upon re-inserting the SD, the data is restored and the system functions normally as it would before the card was pulled. If the card or its data is not available (got corrupted, lost, eaten) - The phone must be "hard reset" to restore full functionality and all user data will be lost.

My guess is this was at least partly done as a method to lock down the security of marketplace apps.
 

MHC48

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Jun 26, 2007
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WP7 will support SD cards, but the functionality is different now. The user data is striped across the SD card and the internal storage. This results in functionality similar to RAID0 - if a member disk is pulled from the set, the entire set ceases to function. Similarly, in WP7, if an SD card is pulled from a deployed device, the device will go into a "reduced functionality" mode - where you are only able to make emergency calls. Upon re-inserting the SD, the data is restored and the system functions normally as it would before the card was pulled. If the card or its data is not available (got corrupted, lost, eaten) - The phone must be "hard reset" to restore full functionality and all user data will be lost.
Is there anything which indicates how large of an SD card WP7 can use? Apparently initially phones will only come with 8 GB of memory, and that on an internal card. That seems way too small if you wanted to store music and videos.Would it concievably be possible, as soon as you bought the phone, before anything additional is loaded, to pull the card, copy everything to a 32 GB card and reinsert it?
 
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RustyGrom

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Is there anything which indicates how large of an SD card WP7 can use? Apparently initially phones will only come with 8 GB of memory, and that on an internal card. That seems way too small if you wanted to store music and videos.Would it concievably be possible, as soon as you bought the phone, before anything additional is loaded, to pull the card, copy everything to a 32 GB card and reinsert it?
8GB is the minimum spec. There will certainly be devices with larger amounts of storage. It should support at least 32GB.
 

mrcrassic

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How is this a performance benefit if most consumer SDs are rated Class 2 (i.e dog slow) and many people prefer to be able to swap cards at will? Class 6 cards are usually pretty expensive, and swapping SD cards on-the-fly is not uncommon...
 

rruffman

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Oct 31, 2007
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What do you mean removable storage? Last I heard it was all non removable?
WM7 phones will have an external storage card slot but it will become apart of the internal drive and not be used in the since of what we currently use it. when an external sd is inserted it is formatted to becomes part of the main internal drive something like a raid system so if you pull out the sd card phone will not boot until you put it back in, and i do believe this is also the same if you replace the card you might have to hard reset to get the phone to work.
 

pmxpmx

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A fred has a test device with 40g (8 internal and a 32g SD card)
You can access the filesystem with the "Remote Tools Framework" along with a filesystem plugin that wraps the Sirep services.
The sirep background services must be running on the device. Unfortunately these need to be flashed in or inserted via imageupdate.
Sirep is the sucesssor of rapi. Some tools include wpget, wpput, wprun etc.
 

cris_rowlands

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if a member disk is pulled from the set, the entire set ceases to function ......... Upon re-inserting the SD, the data is restored and the system functions normally as it would before the card was pulled. If the card or its data is not available (got corrupted, lost, eaten) - The phone must be "hard reset" to restore full functionality and all user data will be lost.
So, that being said.
Whilst Its a well known fact that "external media" such as Micro SD cards will not be user accessable, would it be possible to manually replace the cards?

For example, if a user dared to dismantle his/her device to access the card.
Then remove it, copy the partition on there to a larger piece of media, extend the partition to fill the card & then place that back before re-constructing the rest of the device.

Do you know if that could work, or are there measures put into place which prevent this? I guess some manufacturers may glue cards in, but that can be got around. I mean software wise, would doing this mess up the opperation of the device?

If that wouldnt work, then how about simply replacing the card & doing a hard reset? Any idea if it would simply accomodate the new card?

Im just trying to think of work-arounds as I know many people will be dissapointed with the variety of 8GB devices out there.
 

l3v5y

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So, that being said.
Whilst Its a well known fact that "external media" such as Micro SD cards will not be user accessable, would it be possible to manually replace the cards?

For example, if a user dared to dismantle his/her device to access the card.
Then remove it, copy the partition on there to a larger piece of media, extend the partition to fill the card & then place that back before re-constructing the rest of the device.

Do you know if that could work, or are there measures put into place which prevent this? I guess some manufacturers may glue cards in, but that can be got around. I mean software wise, would doing this mess up the opperation of the device?

If that wouldnt work, then how about simply replacing the card & doing a hard reset? Any idea if it would simply accomodate the new card?

Im just trying to think of work-arounds as I know many people will be dissapointed with the variety of 8GB devices out there.
From what I've heard, the last option there, with forcing a hard reset is likely to be the only one that works, but it should work. OEMs may well glue down the microSD cards though.

I think quite a few devices will be using microSD cards internally, as it lets you release 3 versions of a device with different storage sizes very easily (just slot in an 8GB, 16GB or 32GB uSD card and release it).

I also doubt there will be many only 8GB devices. I know we've only seen leaks of 8GB devices, but it makes sense to test on slightly cheaper hardware, and make sure the OS works on the bare minimum of hardware.