[t13] Fwd: why not H = C = D ModeSense6 for just the header
Thomas Colligan
tcolligan at apple.com
Wed Feb 12 11:41:21 PST 2003
* From the T10 Reflector (t10 at t10.org), posted by:
* Thomas Colligan <tcolligan at apple.com>
*
Jim;
I see the same thing while doing firmware updaters for optical drives. Some
drives use 10 bytes and other use 12 bytes. There are a number of issues
forcing this direction.
Tom Colligan
> From: "Eschmann, Michael K" <michael.k.eschmann at intel.com>
> Date: Wed, 12 Feb 2003 10:52:36 -0800
> To: forum at t13.org, t10 at t10.org
> Subject: RE: [t13] Fwd: why not H = C = D ModeSense6 for just the header
>
> This message is from the T13 list server.
>
>
> Hi Jim,
>
> I'll leave the tape domain to you, but I've seen many CD-ROM's fail on the
> 6-byte format. It may not fail on all, which may be why you see them working
> fine.
>
> 6-byte mode sense:
> struct _MODE_SENSE {
> UCHAR OperationCode;
> UCHAR Reserved1 : 3;
> UCHAR Dbd : 1;
> UCHAR Reserved2 : 1;
> UCHAR LogicalUnitNumber : 3;
> UCHAR PageCode : 6;
> UCHAR Pc : 2;
> UCHAR Reserved3;
> UCHAR AllocationLength;
> UCHAR Control;
> } MODE_SENSE, *PMODE_SENSE;
>
> 10-byte mode sense:
> struct _MODE_SENSE10 {
> UCHAR OperationCode;
> UCHAR Reserved1 : 3;
> UCHAR Dbd : 1;
> UCHAR Reserved2 : 1;
> UCHAR LogicalUnitNumber : 3;
> UCHAR PageCode : 6;
> UCHAR Pc : 2;
> UCHAR Reserved3[4];
> UCHAR AllocationLength[2];
> UCHAR Control;
> } MODE_SENSE10, *PMODE_SENSE10;
>
> You'll see that the allocation length (or Parameter List Length)data doesn't
> line up, so good drivers will convert from 6-to-10 and pad the CDB out (with
> zeros) to a 12 or 16 byte CDB so bad drives (many, I suppose) will function.
>
>
>
> -----Original Message-----
> From: James.C.Hatfield at seagate.com [mailto:James.C.Hatfield at seagate.com]
> Sent: Tuesday, February 11, 2003 3:32 PM
> Cc: forum at t13.org; t10 at t10.org
> Subject: RE: [t13] Fwd: why not H = C = D ModeSense6 for just the header
>
>
> This message is from the T13 list server.
>
>
>
> Most ATAPI tape drives understand the 6-byte CDB.
> Some support the 10-byte format, as well.
>
> ATAPI CD-ROM drives support 6- and 10-byte forms.
>
> The act of supporting the 10-byte CDB implies to <some> drivers that the
> device
> is a CD-ROM type of device.... leading to the driver getting confused.
>
> Halve Phun !!!
> -----------------------------------------------------------------
> Jim Hatfield
> ATA Interface Firmware & T13 (ATA/ATAPI) Standards Representative
> Seagate Technology - PSG
> e-mail: James.C.Hatfield at seagate.com
> s-mail: 389 Disc Drive; Longmont, CO 80501 USA
> voice: 720-684-2120
> fax : 720-684-2711
> ====================================================
>
>
>
> "Eschmann, Michael
> K" To: <t10 at t10.org>,
> <forum at t13.org>
> <michael.k.eschmann@ cc:
> intel.com> Subject: RE: [t13] Fwd: why
> not H = C = D ModeSense6 for just the header
> Sent by:
> owner-forum at t13.org
> No Phone Info
> Available
>
> 02/11/2003 04:19 PM
>
>
>
>
>
>
> This message is from the T13 list server.
>
>
> FYI, this is an issue with the Microsoft driver (supplied with their
> Windows 2000 OS) is not converting the SCSI 6-byte CDB to the 10-byte CDB
> format. ATAPI drives don't understand the 6-byte format of "Mode Sense"
> (am I wrong?), so I believe this issue that MS reported has nothing to do
> with odd "byte" issues that you've been, er, peddling. MKE.
>
>
>
> -----Original Message-----
> From: Pat LaVarre [mailto:LAVARRE at iomega.com]
> Sent: Monday, February 10, 2003 8:22 AM
> To: t10 at t10.org; forum at t13.org
> Subject: [t13] Fwd: why not H = C = D ModeSense6 for just the header
>
>
> This message is from the T13 list server.
>
>
> Newsgroups: microsoft.public.vc
> Date: 2003-02-07 13:39:51 PST
> ...
> http://support.microsoft.com/default.aspx?scid=kb;en-us;Q813908
> SCSI Pass-Through Mode Sense Command May Crash the Computer
> ...
> If a SCSI Mode Sense command (operation code 0x1A) is
> sent by using SCSI pass-through to an ATAPI CD-ROM
> device, you may receive a "Stop" error message on a
> blue screen and the computer may then stop responding
> or may restart. This may occur if the value of the
> Data Length field in the Mode Sense command is less
> than 8. Note that this problem occurs only with the
> 6-byte Mode Sense command (operation code 0x1A), not
> with the 10-byte Mode Sense command (operation code
> 0x5A).
> ...
>
>
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