How to invalidate CD-ROM cache

NTDEV
1

I have written a filter driver in order to cipher CDROM burning in real time
but I have the problem that I don’t know how to invalidate the cache and
when, for example, I change the ciphering key with the CDROM inserted in the
drive, I have to eject it and reload it in order to force the reading of the
PVD (Primary Volume Descriptor) with the new kay. My driver is a LowerFilter
of the CDROM class and I have tried to set the DeviceObject flag
DO_VERIFY_VOLUME and then complete an IRP with STATUS_VERIFY_REQUIRED but it
doesn’t work. Does anybody know how to acomplish this task? I’m using
Windows XP for more information.

Thanks in advance a Happy New Year for all the people.

Jos? Vicente.

2

Joe,

you need to initiate file system unmount process to invalidate OS cache.
FSCTL_DISMOUNT_VOLUME does what you want. If you want to invalidate
CD-ROMs internal (hardware) cache memory you need to read the media in
reversed order with the large gaps between starting LBAs. Like 8000 - 7500

  • … - 500.

Regards,
Anton Kolomyeytsev

I have written a filter driver in order to cipher CDROM burning in real t=
ime
but I have the problem that I don’t know how to invalidate the cache and
when, for example, I change the ciphering key with the CDROM inserted in =
the
drive, I have to eject it and reload it in order to force the reading of =
the
PVD (Primary Volume Descriptor) with the new kay. My driver is a LowerFil=
ter
of the CDROM class and I have tried to set the DeviceObject flag
DO_VERIFY_VOLUME and then complete an IRP with STATUS_VERIFY_REQUIRED but=
it
doesn’t work. Does anybody know how to acomplish this task? I’m using
Windows XP for more information.

Thanks in advance a Happy New Year for all the people.

Jos=E9 Vicente.

3

You’re on right way, you must also support IOCTL_STORAGE_CHECK_VERIFY
and increment the number in this IOCTL.

Max

----- Original Message -----
From: “José Vicente Sánchez Ortega”
To: “NT Developers Interest List”
Sent: Wednesday, January 01, 2003 8:19 PM
Subject: [ntdev] How to invalidate CD-ROM cache

I have written a filter driver in order to cipher CDROM burning in
real time
but I have the problem that I don’t know how to invalidate the cache
and
when, for example, I change the ciphering key with the CDROM inserted
in the
drive, I have to eject it and reload it in order to force the reading
of the
PVD (Primary Volume Descriptor) with the new kay. My driver is a
LowerFilter
of the CDROM class and I have tried to set the DeviceObject flag
DO_VERIFY_VOLUME and then complete an IRP with STATUS_VERIFY_REQUIRED
but it
doesn’t work. Does anybody know how to acomplish this task? I’m using
Windows XP for more information.

Thanks in advance a Happy New Year for all the people.

José Vicente.

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