[T10] Revisiting the RMB (Removable Medium) bit definition

Knight, Frederick Frederick.Knight at netapp.com
Thu Jul 16 19:09:51 PDT 2020


To me, RMB is only about media, and has nothing to do with removing the device server or task manager (or anything else that is not media).

Removal of the device server or task manager (and the associated LUR or I_T Nexus Loss) has nothing to do with the RMB bit.

This kind of description seems to mix those things together.  You also left out the case where RMB=0 indicates that the medium is not removable without resulting in a LOGICAL UNIT NOT SUPPORTED (you'll likely get this error long before you get the POR (29/00) UA notice).  There are probably others.  So it just seems problematic to try and build a list of all the errors that might result if/when an RMB=0 device is removed (because removing the media of an RMB=0 device means you're removing the whole device).

                Fred

From: t10-bounces at t10.org <t10-bounces at t10.org> On Behalf Of Ralph Weber
Sent: Thursday, July 16, 2020 7:27 PM
To: t10 at t10.org
Subject: [T10] Revisiting the RMB (Removable Medium) bit definition

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Regarding the Standard INQUIRY data RMB bit, SPC-6 r02 says...
"A removable medium (RMB) bit set to zero indicates that the medium is not removable. A RMB bit set to one indicates that the medium is removable."

An interesting debate has developed regarding whether a USB "memory stick" is an RMB=0 or an RMB=1 device.

One wag has suggested that the RMB bit definition be conditionalized on the presence/absence of a coincident Logical Unit Reset condition or I_T Nexus Loss condition, something along the lines of...
"A removable medium (RMB) bit set to zero indicates that the medium is not removable without resulting in a Logical Unit Reset condition (see SAM-6) or an I_T Nexus Loss condition (see SAM-6). A RMB bit set to one indicates that the medium is removable with no concurrent Logical Unit Reset condition or I_T Nexus Loss condition."

How says the T10 body politic?

Thanks,

.Ralph
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