USB Mass Storage

[Graham Stevenson]

Hi,

I have a USB mass storage device being developed by
colleagues, and need to interface that to a Windows Forms
application (C#). The device is neither purely a storage
device nor an HID device, it is a combination of the two,
so it seems expedient to use files to communicate PC <->
Device.

The device can read AND WRITE files.

I can write and read the files, but they appear to be
cached ??. If the timestamp is changed by the device,
Windows does not see this change unless an 'Eject'
command is performed on the drive.

Have tried DirectoryInfo and FileInfo classes, as well as
a FileSystemWatcher (but I guess this uses the FileIO OS,
so won't see external changes). None of these can see the
new timestamp until the 'Eject' has been implemented.

How can I achieve this please - or how can I force the
cached file information to be refreshed, so that I can
see the change. Maybe do an 'Eject' programmatically ??? -
could be dangerous just to see a filestamp!!.

Thanks

Graham

Its just a drive.
"Graham Stevenson" <an*******@discussions.microsoft.com> wrote in message
news:02****************************@phx.gbl...

Hi,

I have a USB mass storage device being developed by
colleagues, and need to interface that to a Windows Forms
application (C#). The device is neither purely a storage
device nor an HID device, it is a combination of the two,
so it seems expedient to use files to communicate PC <->
Device.

The device can read AND WRITE files.

I can write and read the files, but they appear to be
cached ??. If the timestamp is changed by the device,
Windows does not see this change unless an 'Eject'
command is performed on the drive.

Have tried DirectoryInfo and FileInfo classes, as well as
a FileSystemWatcher (but I guess this uses the FileIO OS,
so won't see external changes). None of these can see the
new timestamp until the 'Eject' has been implemented.

How can I achieve this please - or how can I force the
cached file information to be refreshed, so that I can
see the change. Maybe do an 'Eject' programmatically ??? -
could be dangerous just to see a filestamp!!.

Thanks

Graham

[Graham Stevenson]

Thanks for the comment, but if its 'Just a Drive' - why
doesn't it update its timestamp, when the device changes
it ?? - until I select 'Eject' for the drive.

Device has a file with given timestamp.
Read this in a .Net app = fine.
Device changes the timestamp.
Read in .Net and it has not changed.
Eject.
Read in .Net and it now has changed.

The point being that the device itself can change the
file parameters - all I want to do is to force Windows to
recognise that change, so that I can monitor it.

Thanks

Graham

-----Original Message-----
Its just a drive.
"Graham Stevenson" <an*******@discussions.microsoft.com> wrote in messagenews:02****************************@phx.gbl...

Hi,

I have a USB mass storage device being developed by
colleagues, and need to interface that to a Windows Forms application (C#). The device is neither purely a storage device nor an HID device, it is a combination of the two, so it seems expedient to use files to communicate PC <-

Device.

The device can read AND WRITE files.

I can write and read the files, but they appear to be
cached ??. If the timestamp is changed by the device,
Windows does not see this change unless an 'Eject'
command is performed on the drive.

Have tried DirectoryInfo and FileInfo classes, as well as a FileSystemWatcher (but I guess this uses the FileIO OS, so won't see external changes). None of these can see the new timestamp until the 'Eject' has been implemented.

How can I achieve this please - or how can I force the
cached file information to be refreshed, so that I can
see the change. Maybe do an 'Eject' programmatically ??? - could be dangerous just to see a filestamp!!.

Thanks

Graham

.

You need to use AutoFlush or call .Flush() i guess as its not written
immediatlly its buffered, right?
"Graham Stevenson" <an*******@discussions.microsoft.com> wrote in message
news:08****************************@phx.gbl...

Thanks for the comment, but if its 'Just a Drive' - why
doesn't it update its timestamp, when the device changes
it ?? - until I select 'Eject' for the drive.

Device has a file with given timestamp.
Read this in a .Net app = fine.
Device changes the timestamp.
Read in .Net and it has not changed.
Eject.
Read in .Net and it now has changed.

The point being that the device itself can change the
file parameters - all I want to do is to force Windows to
recognise that change, so that I can monitor it.

Thanks

Graham

-----Original Message-----
Its just a drive.
"Graham Stevenson" <an*******@discussions.microsoft.com>

wrote in message

news:02****************************@phx.gbl...

Hi,

I have a USB mass storage device being developed by
colleagues, and need to interface that to a Windows Forms application (C#). The device is neither purely a storage device nor an HID device, it is a combination of the two, so it seems expedient to use files to communicate PC <-

Device.

The device can read AND WRITE files.

I can write and read the files, but they appear to be
cached ??. If the timestamp is changed by the device,
Windows does not see this change unless an 'Eject'
command is performed on the drive.

Have tried DirectoryInfo and FileInfo classes, as well as a FileSystemWatcher (but I guess this uses the FileIO OS, so won't see external changes). None of these can see the new timestamp until the 'Eject' has been implemented.

How can I achieve this please - or how can I force the
cached file information to be refreshed, so that I can
see the change. Maybe do an 'Eject' programmatically ??? - could be dangerous just to see a filestamp!!.

Thanks

Graham

.

I (or my PC app) are not writing to the file, so I don't
have anything to Flush.

The USB device is a two-way device, which is capable of
changing a file, hence why the device (not Windows)
changes the timestamp, and I am trying to get Windows
to 'see' this change - without the need for an 'Eject' -
or even with an 'Eject' if I can issue this from my
Windows app - but I don't know how to without the need
for a new device driver.

It must be possible for a windows app to send an 'Eject'
command - as Windows Explorer can do it, but I can't find
how to having trawled MSDN, Web etc.

Graham

-----Original Message-----
You need to use AutoFlush or call .Flush() i guess as its not writtenimmediatlly its buffered, right?
"Graham Stevenson" <an*******@discussions.microsoft.com> wrote in messagenews:08****************************@phx.gbl...

Thanks for the comment, but if its 'Just a Drive' - why
doesn't it update its timestamp, when the device changes it ?? - until I select 'Eject' for the drive.

Device has a file with given timestamp.
Read this in a .Net app = fine.
Device changes the timestamp.
Read in .Net and it has not changed.
Eject.
Read in .Net and it now has changed.

The point being that the device itself can change the
file parameters - all I want to do is to force Windows to recognise that change, so that I can monitor it.

Thanks

Graham

>-----Original Message-----
>Its just a drive.
>
>
>"Graham Stevenson" <an*******@discussions.microsoft.com>

wrote in message

>news:02****************************@phx.gbl...
>> Hi,
>>
>> I have a USB mass storage device being developed by
>> colleagues, and need to interface that to a Windows

Forms

>> application (C#). The device is neither purely a

storage

>> device nor an HID device, it is a combination of the

two,

>> so it seems expedient to use files to communicate

PC <- >
>> Device.
>>
>> The device can read AND WRITE files.
>>
>> I can write and read the files, but they appear to be >> cached ??. If the timestamp is changed by the device, >> Windows does not see this change unless an 'Eject'
>> command is performed on the drive.
>>
>> Have tried DirectoryInfo and FileInfo classes, as well as

>> a FileSystemWatcher (but I guess this uses the

FileIO OS,

>> so won't see external changes). None of these can

see the

>> new timestamp until the 'Eject' has been

implemented. >>
>> How can I achieve this please - or how can I force the >> cached file information to be refreshed, so that I can >> see the change. Maybe do an 'Eject'

programmatically ??? -

>> could be dangerous just to see a filestamp!!.
>>
>> Thanks
>>
>> Graham
>>
>
>
>.
>

.

Cant you use the File system watcher like a normal file? Then you can get
notified once its changed?


<an*******@discussions.microsoft.com> wrote in message
news:0a****************************@phx.gbl...

I (or my PC app) are not writing to the file, so I don't
have anything to Flush.

The USB device is a two-way device, which is capable of
changing a file, hence why the device (not Windows)
changes the timestamp, and I am trying to get Windows
to 'see' this change - without the need for an 'Eject' -
or even with an 'Eject' if I can issue this from my
Windows app - but I don't know how to without the need
for a new device driver.

It must be possible for a windows app to send an 'Eject'
command - as Windows Explorer can do it, but I can't find
how to having trawled MSDN, Web etc.

Graham

-----Original Message-----
You need to use AutoFlush or call .Flush() i guess as

its not written

immediatlly its buffered, right?
"Graham Stevenson" <an*******@discussions.microsoft.com>

wrote in message

news:08****************************@phx.gbl...

Thanks for the comment, but if its 'Just a Drive' - why
doesn't it update its timestamp, when the device changes it ?? - until I select 'Eject' for the drive.

Device has a file with given timestamp.
Read this in a .Net app = fine.
Device changes the timestamp.
Read in .Net and it has not changed.
Eject.
Read in .Net and it now has changed.

The point being that the device itself can change the
file parameters - all I want to do is to force Windows to recognise that change, so that I can monitor it.

Thanks

Graham

>-----Original Message-----
>Its just a drive.
>
>
>"Graham Stevenson" <an*******@discussions.microsoft.com> wrote in message
>news:02****************************@phx.gbl...
>> Hi,
>>
>> I have a USB mass storage device being developed by
>> colleagues, and need to interface that to a Windows
Forms
>> application (C#). The device is neither purely a
storage
>> device nor an HID device, it is a combination of the
two,
>> so it seems expedient to use files to communicate PC <- >
>> Device.
>>
>> The device can read AND WRITE files.
>>
>> I can write and read the files, but they appear to be >> cached ??. If the timestamp is changed by the device, >> Windows does not see this change unless an 'Eject'
>> command is performed on the drive.
>>
>> Have tried DirectoryInfo and FileInfo classes, as well as
>> a FileSystemWatcher (but I guess this uses the FileIO OS,
>> so won't see external changes). None of these can see the
>> new timestamp until the 'Eject' has been implemented. >>
>> How can I achieve this please - or how can I force the >> cached file information to be refreshed, so that I can >> see the change. Maybe do an 'Eject'
programmatically ??? -
>> could be dangerous just to see a filestamp!!.
>>
>> Thanks
>>
>> Graham
>>
>
>
>.
>

.