Microsoft Hybrid Disc Proposal -- Updates

Takaharu Ai ai.takaharu at
Fri Oct 7 03:51:29 PDT 2005

* From the T10 Reflector (t10 at, posted by:
* Takaharu Ai <ai.takaharu at>
Hello Henry, David,

I understand IOCTL_CDROM_RAW_READ is usable to access to the CD Format-layer
even if the Format-layer is assigned to other than the online
Format-layer. But I cannot find any IOCTL for READ command. Could you
teach me the exact name of the IOCTL for READ?

Best Regards,

Harry Ai
Panasonic AVC Networks Company
Osaka, Japan

---------------- Start of the original message ----------------
>From: Henry Gabryjelski <Henry.Gabryjelski at>
>To: mtfuji5 at, t10 at
>Date: Thu, 06 Oct 2005 14:00:16 -0700
>Subject: Microsoft Hybrid Disc Proposal -- Updates
> Dear all,
> Microsoft would like to officially withdraw its remaining multi-session
> hybrid disc proposal.  As you know, this proposal was created to avoid
> data corruption issues when a hardware reset occurs.  We have analyzed
> the situations in which this would occur, and believe that proper
> firmware design (specifically events during initialization) will prevent
> this from being an issue for read-only media for the vast majority of
> customers.
> In addition, my previous e-mail regarding normal READ operation
> restrictions on CDROM media was incorrect.  This information was based
> on my looking at new Microsoft Windows Vista sources.  So, while reads
> past the end of capacity are acceptable for Win2k/XP/Server2003, Windows
> Vista will have different restrictions based on the current media type
> inserted.  In all cases (including Windows Vista), the READ_CD command
> (IOCTL_CDROM_RAW_READ) is never checked for valid LBAs, and must be
> properly handled by the drive firmware.  So, there will always be a
> method to read from past the capacity of the media.
> Thank you for allowing us the extra time to verify that the
> layer-switching proposal from Panasonic/Toshiba will not cause the data
> corruption issue in a majority of cases.
> Sincerely,
> Henry Gabryjelski

----------------- End of the original message -----------------

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