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

Ralph Weber Ralph.Weber at wdc.com
Wed Jul 29 06:47:56 PDT 2020


Proposal 20-082r0<http://www.t10.org/cgi-bin/ac.pl?t=d&f=20-082r0.pdf> SPC-6: Removable Medium Bit Expectations has been posted to bring this discussion thread to the attention of CAP.

Resisting the ongoing calls to put as many words as possible into every standard, the proposal includes only one of the methods for defining a “real” removable medium device discussed in this thread. For the purposes discussed here, only one method is necessary to sufficiently define the standard.

All the best, .Ralph

From: t10-bounces at t10.org <t10-bounces at t10.org> On Behalf Of Michael Webster
Sent: Tuesday, July 21, 2020 7:57 PM
To: t10 at t10.org
Subject: Re: [T10] Revisiting the RMB (Removable Medium) bit definition

I would like to add one other tidbit:  A device reporting RMB=1 in addition to being capable of a state that reports MEDIUM NOT PRESENT, such a device should also properly support and execute an ejection operation of that media when sent a START/STOP UNIT command with Power_Condition=0, LoEj=1, & Start=0.

Mike Webster
Western Digital

From: <t10-bounces at t10.org<mailto:t10-bounces at t10.org>> on behalf of Mike Webster <Mike.Webster at wdc.com<mailto:Mike.Webster at wdc.com>>
Date: Friday, July 17, 2020 at 10:30 AM
To: "t10 at t10.org<mailto:t10 at t10.org>" <t10 at t10.org<mailto:t10 at t10.org>>
Subject: Re: [T10] Revisiting the RMB (Removable Medium) bit definition

I would expect a USB memory stick to report RMB=0 and ejection causes the whole device to be removed from the operating system’s driver stack.  Afterward, such an ejected device would require an unplug/re-plug for the device to respond to anything on USB.

Unless that USB memory stick included a slot for media (e.g. an SD slot) then I would expect the USB memory stick to report RMB=1 and ejection would only cause the device to remove the media, the device would remain in the operating system’s driver stack, and the device would begin reporting CHECK CONDITION, NOT READY, MEDIUM NOT PRESENT for TEST UNIT READY.

Mike Webster
Western Digital

From: <t10-bounces at t10.org<mailto:t10-bounces at t10.org>> on behalf of Curtis Stevens <curtis.stevens at seagate.com<mailto:curtis.stevens at seagate.com>>
Date: Friday, July 17, 2020 at 10:05 AM
To: Kevin D Butt <kdbutt at us.ibm.com<mailto:kdbutt at us.ibm.com>>, Paul Suhler <Paul.Suhler at kioxia.com<mailto:Paul.Suhler at kioxia.com>>
Cc: "t10 at t10.org<mailto:t10 at t10.org>" <t10 at t10.org<mailto:t10 at t10.org>>, "t10-bounces at t10.org<mailto:t10-bounces at t10.org>" <t10-bounces at t10.org<mailto:t10-bounces at t10.org>>
Subject: Re: [T10] Revisiting the RMB (Removable Medium) bit definition

We had this descussion during the original specification development.  For USB, the device controller is removed along with the media.  There is nothing present to respond with an RMB bit.  If however, you plug in a USB floppy, you can have an RMB bit that enables eject function reporting.


---------------------------------------------
Curtis E. Stevens
Technologist
Seagate Technology

E-Mail: Curtis.Stevens at Seagate.com<mailto:Curtis.Stevens at Seagate.com>
Phone: 949-307-5050

________________________________
From: t10-bounces at t10.org<mailto:t10-bounces at t10.org> <t10-bounces at t10.org<mailto:t10-bounces at t10.org>> on behalf of Kevin D Butt <kdbutt at us.ibm.com<mailto:kdbutt at us.ibm.com>>
Sent: Friday, July 17, 2020 9:40 AM
To: Paul Suhler <Paul.Suhler at kioxia.com<mailto:Paul.Suhler at kioxia.com>>
Cc: t10 at t10.org<mailto:t10 at t10.org> <t10 at t10.org<mailto:t10 at t10.org>>; t10-bounces at t10.org<mailto:t10-bounces at t10.org> <t10-bounces at t10.org<mailto:t10-bounces at t10.org>>
Subject: Re: [T10] Revisiting the RMB (Removable Medium) bit definition

I concur with Curtis and Paul.

Kevin D. Butt
SCSI Architect, Tape Firmware, Data Retention Infrastructure
T10 Standards
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt at us.ibm.com<mailto:kdbutt at us.ibm.com>

=========== Interesting Links ===========
[ IBM Tape Storage ]  https://www.ibm.com/it-infrastructure/storage/tape<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ibm.com_it-2Dinfrastructure_storage_tape&d=DwMFAw&c=IGDlg0lD0b-nebmJJ0Kp8A&r=nwHemJnAMSpX8_5V-KnVO4RC6Gz7LepZjtJQCJYPS9M&m=qmU_OTHLUD7JxHe4TLeA_f-Xsszh2_ocvORlu7T4Hs0&s=HnDfWpp9WX_LW5d3u_7ts9PkvrrZjHPwS1fiGXS-WXQ&e=>
[ SSIC - HBA/OS/Switch/Product interoperation ] https://www-304.ibm.com/systems/support/storage/ssic/interoperability.wss<https://urldefense.proofpoint.com/v2/url?u=https-3A__www-2D304.ibm.com_systems_support_storage_ssic_interoperability.wss&d=DwMFAw&c=IGDlg0lD0b-nebmJJ0Kp8A&r=nwHemJnAMSpX8_5V-KnVO4RC6Gz7LepZjtJQCJYPS9M&m=qmU_OTHLUD7JxHe4TLeA_f-Xsszh2_ocvORlu7T4Hs0&s=z-vuLx4Brz9iFumSir-8ol8Hx58dPp2DCikkaF6hkrU&e=>
[ LTO & 3592 ISV Support Matrix ] www.ibm.com/systems/resources/lto_isv_matrix.pdf<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.ibm.com_systems_resources_lto-5Fisv-5Fmatrix.pdf&d=DwMFAw&c=IGDlg0lD0b-nebmJJ0Kp8A&r=nwHemJnAMSpX8_5V-KnVO4RC6Gz7LepZjtJQCJYPS9M&m=qmU_OTHLUD7JxHe4TLeA_f-Xsszh2_ocvORlu7T4Hs0&s=rrZSTuEQ7GAq_7XEwi8xuTtdmPf59IJBwoYpFPYjbLs&e=>
[ LTO SCSI Reference ] http://www-01.ibm.com/support/docview.wss?uid=ssg1S7003556<https://urldefense.proofpoint.com/v2/url?u=http-3A__www-2D01.ibm.com_support_docview.wss-3Fuid-3Dssg1S7003556&d=DwMFAw&c=IGDlg0lD0b-nebmJJ0Kp8A&r=nwHemJnAMSpX8_5V-KnVO4RC6Gz7LepZjtJQCJYPS9M&m=qmU_OTHLUD7JxHe4TLeA_f-Xsszh2_ocvORlu7T4Hs0&s=qWvhXBnECJy0mEu2mPFbqIb3rlui0n-kbb5_SmYra60&e=>
[ 3592 SCSI Reference ] http://www-01.ibm.com/support/docview.wss?uid=ssg1S7003248<https://urldefense.proofpoint.com/v2/url?u=http-3A__www-2D01.ibm.com_support_docview.wss-3Fuid-3Dssg1S7003248&d=DwMFAw&c=IGDlg0lD0b-nebmJJ0Kp8A&r=nwHemJnAMSpX8_5V-KnVO4RC6Gz7LepZjtJQCJYPS9M&m=qmU_OTHLUD7JxHe4TLeA_f-Xsszh2_ocvORlu7T4Hs0&s=-8_Imy5S2joab1z2FxWD4ZGaPIHBmDYMAOJJ-q9HDTk&e=>
===================================



From:        Paul Suhler <Paul.Suhler at kioxia.com<mailto:Paul.Suhler at kioxia.com>>
To:        "Ballard, Curtis C (HPE Storage)" <curtis.ballard at hpe.com<mailto:curtis.ballard at hpe.com>>, Ralph Weber <Ralph.Weber at wdc.com<mailto:Ralph.Weber at wdc.com>>, "t10 at t10.org<mailto:t10 at t10.org>" <t10 at t10.org<mailto:t10 at t10.org>>
Date:        07/17/2020 09:19
Subject:        [EXTERNAL] Re: [T10] Revisiting the RMB (Removable Medium) bit definition
Sent by:        t10-bounces at t10.org<mailto:t10-bounces at t10.org>
________________________________


I agree with Curtis about the need to be able to report NOT READY, MEDIUM NOT PRESENT. I’ve worked on both SSC and SBC devices like that.



Paul

Kioxia



From:t10-bounces at t10.org <t10-bounces at t10.org<mailto:t10-bounces at t10.org>> On Behalf Of Ballard, Curtis C (HPE Storage)
Sent: Friday, July 17, 2020 9:54 AM
To: Ralph Weber <Ralph.Weber at wdc.com<mailto:Ralph.Weber at wdc.com>>; t10 at t10.org<mailto:t10 at t10.org>
Subject: Re: [T10] Revisiting the RMB (Removable Medium) bit definition



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<mailto:t10-bounces at t10.org><t10-bounces at t10.org<mailto:t10-bounces at t10.org>> On Behalf Of Ralph Weber
Sent: Thursday, July 16, 2020 5:27 PM
To: t10 at t10.org<mailto: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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