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

Ballard, Curtis C (HPE Storage) curtis.ballard at hpe.com
Fri Jul 17 07:53:46 PDT 2020


Ralph,

That bit is used with tape drives and was used with SCSI magneto optical drives, DVD drives, etc.

Even system I've used with that bit set to one, and I've worked with several devices from different manufacturers that set that bit to one, only use it in reference to the media with no device server disruption other than the expected Unit Attention condition transitions as the media is removed and re-loaded.

SCSI devices should only set that bit to one if they are able to report an 02h/3Ah/00h - NOT READY, MEDIUM NOT PRESENT

Curtis Ballard
Hewlett Packard Enterprise

From: t10-bounces at t10.org <t10-bounces at t10.org> On Behalf Of Ralph Weber
Sent: Thursday, July 16, 2020 5:27 PM
To: t10 at t10.org
Subject: [T10] Revisiting the RMB (Removable Medium) bit definition

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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