UDO drives and 8K sector media

Swati_Chawdhary-2 · August 18, 2004, 1:26am

Am writing drivers for a UDO drive with 8K sector media.
My question: 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.

Regards,
Swati

OSR_Community_User · August 26, 2004, 11:25pm

Today Windows does not properly support devices whose sector size is
greater then the page size of the system. For x86 systems the page size
is 4K.

These types of devices have been an issue and some work is being done to
support them at a basic level so the system does not crash when it sees
this type of device. We are not planning on fixing MM, the cache
manager, or our file systems to handle these types of devices. They are
fixing NtLoader and the kernel so these devices can be mounted by RAW
and you can do direct IO to them.

I have requested some information on what OS’s they are going to release
this fix for. I will let you know what they say.

I don’t know if it is feasible to write a storage stack filter to do
this (not my area of expertise) but I know you can write a driver for
your hardware that handles the 4K to 8K conversions because I know other
companies have done this. If you want to use Microsoft supplied file
systems you will need to write your own driver that handles this.

Neal Christiansen
Microsoft File System Filter Group Lead
This posting is provided “AS IS” with no warranties, and confers no
rights

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Swati
Sent: Tuesday, August 17, 2004 10:25 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] UDO drives and 8K sector media

Am writing drivers for a UDO drive with 8K sector media.
My question: 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.

Regards,
Swati

Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

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OSR_Community_User · August 29, 2004, 1:00pm

I have confirmed that they are going to fix this for Windows 2000,
Windows XP, and Server 2003.

I did make a mistake in my description of what will be supported. These
types of devices will NOT be mountable by the RAW file system. That was
the original plan but it has since changed. You will only have SCSI
pass-through access to devices whose sector size is greater then the
page size of the OS.

Neal Christiansen
Microsoft File System Filter Group Lead
This posting is provided “AS IS” with no warranties, and confers no
rights

-----Original Message-----
From: Neal Christiansen
Sent: Thursday, August 26, 2004 8:24 PM
To: Windows File Systems Devs Interest List
Subject: RE: [ntfsd] UDO drives and 8K sector media