Template Version: @(#)sac_nextcase 1.64 07/13/07 SMI
This information is Copyright 2007 Sun Microsystems
1. Introduction
1.1. Project/Component Working Name:
Tape Self Identification
1.2. Name of Document Author/Supplier:
Author: Larry Liu
1.3 Date of This Document:
23 October, 2007
4. Technical Description
Problem
-----------
Today in Solaris, there are two methods to support a tape drive:
adding entries in st.conf, or adding entries in st_conf.c.
Both of them are static mechanisms and cost tape users or developers
time to figure out what the configuration data is. To support
a new tape drive, the developer needs to refer to the manual,
find the configuration data, add a static entry in st_conf.c,
test, then integrate it into solaris. This takes at least 2 months.
Sometimes, the official tape reference manual is not available
before it's RR date. So there is no way for us to find out what
the configuration data should be. This influences the Solaris'
official support for the tape drives and influences Sun's revenue.
Solution
------------
We propose to let the st driver query the configuration from tape
drives if there is no static entry in st.conf and st_conf.c. By
sending SCSI-3 commands, some of which are optional, during
attach time, the tape drives which support those commands are
automatically configured.
There are four methods to configure a tape drive.
1. add entry in st.conf
2. add entry in st_conf.c
3. tape self identification
4. default
st driver tries to configure the tape device in order proceeding
from method 1 to method 4 and will finish the configuration when
the first of these methods completes successfully. The default
configuration is always available.
Querying the configuration from a tape drive is performed only
after failing to read the configuration properties in st.conf and
st_conf.c. So this method has no influence on the tape drives
SUN already supports and customers can still add their own
configuration data in st.conf which will override entries in
st_conf.c and avoid querying the configuration from the tape drive.
Interface Binding
-------------------
This change imports the following interfaces between operating system
and SCSI tape devices.
_______________________________________________________________
| Interface Name | Proposed Stability | Specified in What |
| | Classification | document |
|___________________|______________________|____________________|
| | | |
| REPORT DENSITT | Committed | ssc3r03c, page 102 |
| SUPPORT | | |
| | | |
| | | |
| REPORT SUPPORTED | Committed | spc4r06, page 229 |
| OPERATION CODES | | With Command |
| | | timeouts descriptor|
| | | in spc4r06, |
| | | page 234 |
|___________________|______________________|____________________|
Man page of changes
----------------------------------
This man page will be integrated into st(7D)
Write Operation
Writing from the beginning of tape is performed in the
user-specified format. The original tape format is used for
appending onto previously written tapes.
Tape Configuration
| The st tape driver has a built-in configuration table for most
| Sun supported tape drives. For those tape drives that are not
| in the table, st driver tries to read the configuration from a
| tape drive through optional SCSI-3 commands. To support the
| addition of third party tape devices which are either not in
| the built-in configuration table or not able to report their
| configuration, device information can be supplied in st.conf
| as global properties that apply to each node, or as properties
| that are applicable to one node only. By supplying the
| information in st.conf, the built-in configuration is overridden
| and st driver will not query the configuration from tape drives.
| The st driver looks for the property called "tape-config-list."
| The value of this property is a list of triplets, where each
| triplet consists of three strings.
The formal syntax is:
tape-config-list = <triplet> [, <triplet> *];
6. Resources and Schedule
6.4. Steering Committee requested information
6.4.1. Consolidation C-team Name:
ON
6.5. ARC review type: Automatic
6. Resources and Schedule
6.4. Steering Committee requested information
6.4.1. Consolidation C-team Name:
ON
6.5. ARC review type: Automatic
6.6. ARC Exposure: open
