8K/4K sector size translation filter

NTDEV
1

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k sector
devices in Windows?

If there is no such support from windows, is it feasible to write a 8K to 4K
sector size translation filter that would sit just above the removable
device and present it as a 4K sector device to Windows? Where this filter
should be in the stack? Once the filter is plugged in, will i have FAT/NTFS
support also for the removable device?

Pls help me.

Regards,
Swati

2

Having a sector size > PAGE_SIZE = asking for major problems in Windows.
The cache manager is not designed for such sectors.

So, it is better to emulate the 4KB sectors (if not 512byte one).

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

----- Original Message -----
From: “Swati”
To: “Windows System Software Devs Interest List”
Sent: Wednesday, August 18, 2004 8:40 AM
Subject: [ntdev] 8K/4K sector size translation filter

> Hi Everyone,
>
> I need to write drivers for a removable device. The device supports 8k
> sector size. My question is that: Is there any native support for 8k sector
> devices in Windows?
>
> If there is no such support from windows, is it feasible to write a 8K to 4K
> sector size translation filter that would sit just above the removable
> device and present it as a 4K sector device to Windows? Where this filter
> should be in the stack? Once the filter is plugged in, will i have FAT/NTFS
> support also for the removable device?
>
> Pls help me.
>
> Regards,
> Swati
>
>
> —
> Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com

3

The maximum sector size for any randomly-accessible storage device
(cdrom/disk/WORM) is equal to PAGE_SIZE. Some versions of the OS may
also prevent functionality on sector sizes that are not equal to 512
bytes.

It’s a very good idea not to design these types of devices, or to have
the hardware implement read/modify/write. If you have the opportunity
to do this, please consider exposing 4k sectors from the device.

If the hardware is already shipping, the best place to put such a filter
is dependent upon the applications that you expect to work with. For
most purposes, a lower filter driver for storage will work.
Unfortunately, this happens to be one of the least-documented and
most-complex locations to insert a filter driver(*) – I’ve had to do
this a few times, and my next goal was always to find a way to remove
the filter driver. :slight_smile:

Things to be concerned about:

(1) To serialize or not to serialize? Serialization of all the IO makes
handling error cases easier.

(2) Performance, or it just works? For performance, you’d need to put
IO into a custom queue which collates any two 4k writes to the same
“real” sector into a single write. This is more complex, of course.

(3) Restore the original CDB (in the SRB) when you’re done.

(4) Consider IOCTL_SCSI_PASS_THROUGH and IOCTL_SCSI_PASS_THROUGH_DIRECT.
Either fail them, or do the same read/modify/write cycle as needed for
them. This is an easy area to have security bugs, so I suggest failing
them in the release version of the driver.

(5) Try very hard not to initiate any additional state-changing IO for
any read/write irp. Doing Read/Modify/Write directly using the original
irp is OK, as long as all errors are propogated back to the original
SRB.

(6) Forward progress. The storage stack ensure forward progress even in
zero-memory conditions (presuming that START_DEVICE succeeded). Make
sure that you have sufficient resources allocated to handle at least one
request. Serialization means you don’t need to have any fallback code
that serializes IO on allocation failures.

These are just the first things that popped into my head. I wish you
luck, as you are entering a particularly unfriendly area of the Windows
driver architecture. :frowning:

.

(*) At least, one which doesn’t just modify existing irps, and which
initiates additional IO for a single irp. You may be able to avoid this
problem, if you’re careful.

-----Original Message-----
From: Swati [mailto:xxxxx@tataelxsi.co.in]
Sent: Tuesday, August 17, 2004 9:41 PM
Subject: 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k
sector
devices in Windows?

If there is no such support from windows, is it feasible to write a 8K
to 4K
sector size translation filter that would sit just above the removable
device and present it as a 4K sector device to Windows? Where this
filter
should be in the stack? Once the filter is plugged in, will i have
FAT/NTFS
support also for the removable device?

Pls help me.

Regards,
Swati

4

Hmmmm… I have tried sector sizes up to 4K, but never went over a page. A
simple virtual disk driver would be easy to mock up and test.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 9:41 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k sector
devices in Windows?

If there is no such support from windows, is it feasible to write a 8K to 4K
sector size translation filter that would sit just above the removable
device and present it as a 4K sector device to Windows? Where this filter
should be in the stack? Once the filter is plugged in, will i have FAT/NTFS
support also for the removable device?

Pls help me.

Regards,
Swati

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

This message was checked by NOD32 antivirus system.
http://www.nod32.com

5

You’ll end with testing all of the hard disk management tools available
on the market. I think you’re too old to see
the finial result of your test :slight_smile:

And I’ve seen too many of disk management tools in source code to know
quite a lot of people were too lazy just
to think about sector size can be something different from 512 bytes.

Jeffry told already “try to stay away from non-512 byte sectors” and
trying to add/argue something to this is simply stupid…

P.S. We were experimenting with large sector sizes. Just wanted to have
volume snapshot implementation where
every single sector would be represented with two ULONG record – image
file index and basic offset in sectors. So having
large sectors allowed to keep comparably small “clean/dirty” sector
location map and not to mess with partically written sector
groups. Good idea, but 64K-128K sectors just don’t work :slight_smile: And even 4K
ones are too small to have 1:1 map acceptable in size.

Regards,
Anton A. Kolomyeytsev

RocketDivision.Com – Toolkits for Network and Storage Kernel Software
Developers

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 12:21 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

Hmmmm… I have tried sector sizes up to 4K, but never went over a page.
A simple virtual disk driver would be easy to mock up and test.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 9:41 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k
sector devices in Windows?

If there is no such support from windows, is it feasible to write a 8K
to 4K sector size translation filter that would sit just above the
removable device and present it as a 4K sector device to Windows? Where
this filter should be in the stack? Once the filter is plugged in, will
i have FAT/NTFS support also for the removable device?

Pls help me.

Regards,
Swati

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

This message was checked by NOD32 antivirus system. http://www.nod32.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cooldev.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

6

My God man, have you heard of clusters?

:slight_smile:

P.S. That was a smile on the previous line; I am not poo pooing anyone.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Anton A.
Kolomyeytsev (CoolDev.Com)
Sent: Wednesday, August 18, 2004 3:20 PM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

You’ll end with testing all of the hard disk management tools available
on the market. I think you’re too old to see
the finial result of your test :slight_smile:

And I’ve seen too many of disk management tools in source code to know
quite a lot of people were too lazy just
to think about sector size can be something different from 512 bytes.

Jeffry told already “try to stay away from non-512 byte sectors” and
trying to add/argue something to this is simply stupid…

P.S. We were experimenting with large sector sizes. Just wanted to have
volume snapshot implementation where
every single sector would be represented with two ULONG record – image
file index and basic offset in sectors. So having
large sectors allowed to keep comparably small “clean/dirty” sector
location map and not to mess with partically written sector
groups. Good idea, but 64K-128K sectors just don’t work :slight_smile: And even 4K
ones are too small to have 1:1 map acceptable in size.

Regards,
Anton A. Kolomyeytsev

RocketDivision.Com – Toolkits for Network and Storage Kernel Software
Developers

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 12:21 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

Hmmmm… I have tried sector sizes up to 4K, but never went over a page.
A simple virtual disk driver would be easy to mock up and test.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 9:41 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k
sector devices in Windows?

If there is no such support from windows, is it feasible to write a 8K
to 4K sector size translation filter that would sit just above the
removable device and present it as a 4K sector device to Windows? Where
this filter should be in the stack? Once the filter is plugged in, will
i have FAT/NTFS support also for the removable device?

Pls help me.

Regards,
Swati

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

This message was checked by NOD32 antivirus system. http://www.nod32.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cooldev.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

This message was checked by NOD32 antivirus system.
http://www.nod32.com

7

>>P.S. We were experimenting with large sector sizes. Just wanted to have
volume snapshot implementation where every single sector would be
represented with two ULONG record – image file index and basic offset in
sectors. So having large sectors allowed to keep comparably small
clean/dirty" sector location map and not to mess with partically written
sector groups. Good idea, but 64K-128K sectors just don’t work :slight_smile: And even
4K ones are too small to have 1:1 map acceptable in size.<<

Why do you need an index into the image file for your dirty bitmap? Also,
using clusters will reduce the count you can also… I better shut up before
I give away the store :slight_smile:

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 12:21 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

Hmmmm… I have tried sector sizes up to 4K, but never went over a page.
A simple virtual disk driver would be easy to mock up and test.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 9:41 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k
sector devices in Windows?

If there is no such support from windows, is it feasible to write a 8K
to 4K sector size translation filter that would sit just above the
removable device and present it as a 4K sector device to Windows? Where
this filter should be in the stack? Once the filter is plugged in, will
i have FAT/NTFS support also for the removable device?

Pls help me.

Regards,
Swati

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

This message was checked by NOD32 antivirus system. http://www.nod32.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cooldev.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

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This message was checked by NOD32 antivirus system.
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8

At SCSI hard disk device firmware level? NO!

You just don’t treat this topic (no only this one but virtually every
one) seriously. I wonder why
you keep writing to this list? Just for fun?

Regards,
Anton A. Kolomyeytsev

RocketDivision.Com – Toolkits for Network and Storage Kernel Software
Developers

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 1:50 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

My God man, have you heard of clusters?

:slight_smile:

P.S. That was a smile on the previous line; I am not poo pooing anyone.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Anton A.
Kolomyeytsev (CoolDev.Com)
Sent: Wednesday, August 18, 2004 3:20 PM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

You’ll end with testing all of the hard disk management tools available
on the market. I think you’re too old to see the finial result of your
test :slight_smile:

And I’ve seen too many of disk management tools in source code to know
quite a lot of people were too lazy just
to think about sector size can be something different from 512 bytes.

Jeffry told already “try to stay away from non-512 byte sectors” and
trying to add/argue something to this is simply stupid…

P.S. We were experimenting with large sector sizes. Just wanted to have
volume snapshot implementation where every single sector would be
represented with two ULONG record – image file index and basic offset
in sectors. So having large sectors allowed to keep comparably small
“clean/dirty” sector location map and not to mess with partically
written sector
groups. Good idea, but 64K-128K sectors just don’t work :slight_smile: And even 4K
ones are too small to have 1:1 map acceptable in size.

Regards,
Anton A. Kolomyeytsev

RocketDivision.Com – Toolkits for Network and Storage Kernel Software
Developers

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 12:21 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

Hmmmm… I have tried sector sizes up to 4K, but never went over a page.
A simple virtual disk driver would be easy to mock up and test.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 9:41 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k
sector devices in Windows?

If there is no such support from windows, is it feasible to write a 8K
to 4K sector size translation filter that would sit just above the
removable device and present it as a 4K sector device to Windows? Where
this filter should be in the stack? Once the filter is plugged in, will
i have FAT/NTFS support also for the removable device?

Pls help me.

Regards,
Swati

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

This message was checked by NOD32 antivirus system. http://www.nod32.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cooldev.com
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unsubscribe send a blank email to xxxxx@lists.osr.com

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9

B/s there is unlimited number of the “rollbacks”. You can have only
single shapshot (your way)
to recover. Or you can have unlimited sectors “history” (so you can
backtrace every
volume mount sequence). Would you prefer one “If I could turn back time”
(c) … or have a
possibility to start the game over and over again from the different
places? Who knows, maybe
last backup you’ve created already has DAMAGED data?

We’ve ended with “sector groups” (OK, you can call them clusters but I’d
prefer to use this term
with file system only) but having “cluster” partially written forces the
code write all the blocks current
“cluster” has. B/s there is single entry for them all! With small writes
performance is far from perfect…

Whoops… The movie stopped at the most interesting place :slight_smile:

Regards,
Anton A. Kolomyeytsev

RocketDivision.Com – Toolkits for Network and Storage Kernel Software
Developers

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 1:52 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

>P.S. We were experimenting with large sector sizes. Just wanted to
>have
volume snapshot implementation where every single sector would be
represented with two ULONG record – image file index and basic offset
in sectors. So having large sectors allowed to keep comparably small
clean/dirty" sector location map and not to mess with partically written
sector groups. Good idea, but 64K-128K sectors just don’t work :slight_smile: And
even 4K ones are too small to have 1:1 map acceptable in size.<<

Why do you need an index into the image file for your dirty bitmap?
Also, using clusters will reduce the count you can also… I better shut
up before I give away the store :slight_smile:

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 12:21 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

Hmmmm… I have tried sector sizes up to 4K, but never went over a page.
A simple virtual disk driver would be easy to mock up and test.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 9:41 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k
sector devices in Windows?

If there is no such support from windows, is it feasible to write a 8K
to 4K sector size translation filter that would sit just above the
removable device and present it as a 4K sector device to Windows? Where
this filter should be in the stack? Once the filter is plugged in, will
i have FAT/NTFS support also for the removable device?

Pls help me.

Regards,
Swati

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

This message was checked by NOD32 antivirus system. http://www.nod32.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cooldev.com
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unsubscribe send a blank email to xxxxx@lists.osr.com

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10

Of course

Jamey
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Anton A.
Kolomyeytsev (CoolDev.Com)
Sent: Wednesday, August 18, 2004 4:06 PM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

At SCSI hard disk device firmware level? NO!

You just don’t treat this topic (no only this one but virtually every
one) seriously. I wonder why
you keep writing to this list? Just for fun?

Regards,
Anton A. Kolomyeytsev

RocketDivision.Com – Toolkits for Network and Storage Kernel Software
Developers

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 1:50 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

My God man, have you heard of clusters?

:slight_smile:

P.S. That was a smile on the previous line; I am not poo pooing anyone.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Anton A.
Kolomyeytsev (CoolDev.Com)
Sent: Wednesday, August 18, 2004 3:20 PM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

You’ll end with testing all of the hard disk management tools available
on the market. I think you’re too old to see the finial result of your
test :slight_smile:

And I’ve seen too many of disk management tools in source code to know
quite a lot of people were too lazy just
to think about sector size can be something different from 512 bytes.

Jeffry told already “try to stay away from non-512 byte sectors” and
trying to add/argue something to this is simply stupid…

P.S. We were experimenting with large sector sizes. Just wanted to have
volume snapshot implementation where every single sector would be
represented with two ULONG record – image file index and basic offset
in sectors. So having large sectors allowed to keep comparably small
“clean/dirty” sector location map and not to mess with partically
written sector
groups. Good idea, but 64K-128K sectors just don’t work :slight_smile: And even 4K
ones are too small to have 1:1 map acceptable in size.

Regards,
Anton A. Kolomyeytsev

RocketDivision.Com – Toolkits for Network and Storage Kernel Software
Developers

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 12:21 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

Hmmmm… I have tried sector sizes up to 4K, but never went over a page.
A simple virtual disk driver would be easy to mock up and test.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 9:41 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k
sector devices in Windows?

If there is no such support from windows, is it feasible to write a 8K
to 4K sector size translation filter that would sit just above the
removable device and present it as a 4K sector device to Windows? Where
this filter should be in the stack? Once the filter is plugged in, will
i have FAT/NTFS support also for the removable device?

Pls help me.

Regards,
Swati

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

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11

We can do that too.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Anton A.
Kolomyeytsev (CoolDev.Com)
Sent: Wednesday, August 18, 2004 4:22 PM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

B/s there is unlimited number of the “rollbacks”. You can have only
single shapshot (your way)
to recover. Or you can have unlimited sectors “history” (so you can
backtrace every
volume mount sequence). Would you prefer one “If I could turn back time”
(c) … or have a
possibility to start the game over and over again from the different
places? Who knows, maybe
last backup you’ve created already has DAMAGED data?

We’ve ended with “sector groups” (OK, you can call them clusters but I’d
prefer to use this term
with file system only) but having “cluster” partially written forces the
code write all the blocks current
“cluster” has. B/s there is single entry for them all! With small writes
performance is far from perfect…

Whoops… The movie stopped at the most interesting place :slight_smile:

Regards,
Anton A. Kolomyeytsev

RocketDivision.Com – Toolkits for Network and Storage Kernel Software
Developers

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 1:52 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

>P.S. We were experimenting with large sector sizes. Just wanted to
>have
volume snapshot implementation where every single sector would be
represented with two ULONG record – image file index and basic offset
in sectors. So having large sectors allowed to keep comparably small
clean/dirty" sector location map and not to mess with partically written
sector groups. Good idea, but 64K-128K sectors just don’t work :slight_smile: And
even 4K ones are too small to have 1:1 map acceptable in size.<<

Why do you need an index into the image file for your dirty bitmap?
Also, using clusters will reduce the count you can also… I better shut
up before I give away the store :slight_smile:

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 12:21 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

Hmmmm… I have tried sector sizes up to 4K, but never went over a page.
A simple virtual disk driver would be easy to mock up and test.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 9:41 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k
sector devices in Windows?

If there is no such support from windows, is it feasible to write a 8K
to 4K sector size translation filter that would sit just above the
removable device and present it as a 4K sector device to Windows? Where
this filter should be in the stack? Once the filter is plugged in, will
i have FAT/NTFS support also for the removable device?

Pls help me.

Regards,
Swati

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

This message was checked by NOD32 antivirus system. http://www.nod32.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cooldev.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

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http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

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http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cooldev.com
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12

Also, you can track clusters in the bitmap and do sector stores. I know this
for sure.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Anton A.
Kolomyeytsev (CoolDev.Com)
Sent: Wednesday, August 18, 2004 4:22 PM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

B/s there is unlimited number of the “rollbacks”. You can have only
single shapshot (your way)
to recover. Or you can have unlimited sectors “history” (so you can
backtrace every
volume mount sequence). Would you prefer one “If I could turn back time”
(c) … or have a
possibility to start the game over and over again from the different
places? Who knows, maybe
last backup you’ve created already has DAMAGED data?

We’ve ended with “sector groups” (OK, you can call them clusters but I’d
prefer to use this term
with file system only) but having “cluster” partially written forces the
code write all the blocks current
“cluster” has. B/s there is single entry for them all! With small writes
performance is far from perfect…

Whoops… The movie stopped at the most interesting place :slight_smile:

Regards,
Anton A. Kolomyeytsev

RocketDivision.Com – Toolkits for Network and Storage Kernel Software
Developers

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 1:52 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

>P.S. We were experimenting with large sector sizes. Just wanted to
>have
volume snapshot implementation where every single sector would be
represented with two ULONG record – image file index and basic offset
in sectors. So having large sectors allowed to keep comparably small
clean/dirty" sector location map and not to mess with partically written
sector groups. Good idea, but 64K-128K sectors just don’t work :slight_smile: And
even 4K ones are too small to have 1:1 map acceptable in size.<<

Why do you need an index into the image file for your dirty bitmap?
Also, using clusters will reduce the count you can also… I better shut
up before I give away the store :slight_smile:

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jamey Kirby
Sent: Thursday, August 19, 2004 12:21 AM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] 8K/4K sector size translation filter

Hmmmm… I have tried sector sizes up to 4K, but never went over a page.
A simple virtual disk driver would be easy to mock up and test.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 9:41 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] 8K/4K sector size translation filter

Hi Everyone,

I need to write drivers for a removable device. The device supports 8k
sector size. My question is that: Is there any native support for 8k
sector devices in Windows?

If there is no such support from windows, is it feasible to write a 8K
to 4K sector size translation filter that would sit just above the
removable device and present it as a 4K sector device to Windows? Where
this filter should be in the stack? Once the filter is plugged in, will
i have FAT/NTFS support also for the removable device?

Pls help me.

Regards,
Swati

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

This message was checked by NOD32 antivirus system. http://www.nod32.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cooldev.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
unsubscribe send a blank email to xxxxx@lists.osr.com

__________ NOD32 1.847 (20040818) Information __________

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Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cooldev.com
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Questions? First check the Kernel Driver FAQ at
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You are currently subscribed to ntdev as: xxxxx@storagecraft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

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