REPORT LUNs command

gop at us.ibm.com gop at us.ibm.com
Tue Jan 26 12:03:23 PST 1999


* From the T10 Reflector (t10 at symbios.com), posted by:
* gop at us.ibm.com
*
Berrie,
The answer to your questions are as follows:

1-The LUN list length = (number of LUNs) * 8
Note that the number of LUNs could be the number of supported LUNs or the
number of installed LUNs that is up to the implementation.

2-The maximum length of the page is something like 4000 MBytes. This could
occur if you supported 500 Mega LUNs. This is possible because of the
8-byte LUN address. Only non-SCC parallel devices are limited to 64 LUNs.
SCC devices and other serial interfaces allow more devices to be attached.
So the length is only limited if you system is a single level non-SCC
device running parallel SCSI.

3- The structure of the 8-byte LUN field is defined in SAM-2 section 4.1.
The 8-byte address for LUN 0 is always 00h 00h 00h 00h 00h 00h 00h 00h. As
an example LUN 1 would be 00h 01h 00h 00h 00h 00h 00h 00h if your system
used the Peripheral Device Addressing Method.  Again this is all defined in
section 4.11 of SAM-2.

Bye for now,
George Penokie

Dept EGB  114-2 N212
E-Mail:    gop at us.ibm.com
Internal:  553-5208
External: 507-253-5208   FAX: 507-253-5208




"Barrie Mullins" <bmullins at eurologic.com> on 01/08/99 04:12:22 AM

To:   t10 at Symbios.COM
cc:   "Barrie Mullins" <bmullins at eurologic.com> (bcc: George
      Penokie/Rochester/IBM)
Subject:  REPORT LUNs command





* From the T10 Reflector (t10 at symbios.com), posted by:
* "Barrie Mullins" <bmullins at eurologic.com>
*
I am at present implementing a unit that is going to support multiple LUNs
and I would like to support the REPORT LUN command specified in the SPC-3
Revision 11a.

My question deals with the LUN reporting parameter list format.

1. Is the following correct?
The LUN list length = (the number of supported LUNs) * 8.

2. If the above is correct then the maximum length of the page = 8 + 64 * 8
= 520 bytes.

3. What information is to be stored in the 8 byte location for each LUN.
Bytes 8 to 15 are used to describe LUN 0.
3.1 Should I insert the LUN number in the LSB?
3.2 The 8 bytes consist of 64 bits, does this relate to the LUN number,
should I set the relevant bit for the LUN that I am dealing with? for LUN 0
should the bytes 8  to 15 be as shown below.

Byte
8 = 0000 0000
9 = 0000 0000
10 = 0000 0000
11 = 0000 0000
12 = 0000 0000
13 = 0000 0000
14 = 0000 0000
15 = 0000 0001

Regards,
Barrie Mullins.


Barrie Mullins,
Firmware Design Engineer
Eurologic Systems Ltd.
PHONE: +353-1-2061200
FAX:   +353-1-2061299, 2061291/92
Email:    bmullins at eurologic.com

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