## Storage Device Driver Reference

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### SCSI-Specific Parameters

The following diagram illustrates a SCSI adapter device driver parameter structure:

    SCSI-Driver-Parameters::= ---- /<!>SN -------------------
                               |-- /<!>ET -
                               |-- /V     -|
                               \------------/

    SCSI-Adapter-Parameters::=
             --- /A:d ---- /S:d   ------- /<!>DM -----
                        |-- /P:hhhh- |-- /<!>SN -
                        \------------/ |-- /<!>SN -|
                                       |-- /<!>ET -|
                                       |-- /I     -|
                                       \------------/

    SCSI-Unit-Parameters::= ----- /<!>DM  ------------------
                             |-- /<!>SM  -         |
                             ||-- /<!>SN  -|         |
                             ||-- /<!>ET  -|         |
                             ||-- /<!>HCR -|         |
                             ||-- /<!>HCW -|         |
                             |\-------------/         |
                             \------------------------/

    SCSI-Target-IDs::=      ----- d     ------------ (d=0-7)
                             |\-- (d,d) --/|
                             \--- ,     ---/

Note: All SCSI adapter device drivers must support the following parameters:

/VVerbose
/AAdapter Identification
/DMEnable/Disable DASD Manager Support
/SMEnable/Disable SCSI Manager Support

To insure support of various CD-ROM drives the implementation of the following parameters is recommended:

/SNEnable/Disable Synchronous Negotiation
/ETEnable/Disable Embedded Target Support

Support of the remaining parameters is optional.

SCSI Adapter Device Driver Parameters

/SNSynchronous Negotiation

This parameter indicates a SCSI Host Adapter should attempt to initiate synchronous data transfers. Negating this parameter (/!SN) indicates that the SCSI Host Adapter must not attempt to initiate synchronous data transfers.

/ETEmbedded Targets

This parameter indicates that the adapter device driver must search each SCSI Target for logical units. Negating this parameter (/!ET) indicates that the adapter device driver should only check LUN 0 on each SCSI Target regardless of whether additional Logical Units are present.

/VVerbose

This parameter indicates that the adapter device driver must display diagnostic information during the OS/2 system initialization. The DevHlp_ Save_Message device help routine should be used to display this information .

The following format for the displayed information is recommended:

    --------------------------------------------------------------------------

    XYZ-2010 OS/2 2.0 Driver (yymmdd)
    Copyright (c) 1993 XYZ Inc. All Rights Reserved
     Adapter: 0 Base Port: 0123  IRQ: 10
      Target: 0 LUN: 0  SCSI_Inquiry_Data (Bytes 8-35)
      Target: 1 LUN: 0  SCSI_Inquiry_Data
      Target: 2 LUN: 0  SCSI_Inquiry_Data

    --------------------------------------------------------------------------

/A:dAdapter Index

This parameter specifies the ordering of adapters in the DEVICETABLE returned by the adapter device driver. Normally, adapters are numbered consecutively, starting at 0.

/S:dAdapter Slot ID

For host systems with individually addressable slots, the adapter device driver can designate the location of a host adapter by its slot number, according to the host system's slot addressing scheme. Typically <d> is a small 0-based number specifying the host system slot.

/P::hhhhAdapter Base I/O Port Address

For host systems with non-addressable slots, the adapter device driver can designate the location of a host adapter by its base I/O port address. Typically, <hhhh> is a 3-4 digit hexadecimal number.

Note: In cases where a specific adapter designation is not made, the adapter device driver can apply its own ordering, based on either the base I/O port address or the physical slot address.

Note: In general, an adapter device driver should choose to support only one of the above addressing methods. If an adapter device driver supports more than one addressing method, it must not permit a mix of addressing methods on a single line.

/DMDASD Manager Support

This parameter indicates that this unit must be supported by the IBM- supplied DASD device manager ( OS2DASD.DMD). If this parameter is not specified, the default is to permit DASD device manager support. If this parameter is negated, the adapter device driver must set the UF_NODASD_SUPT flag in the UnitFlags field of the DEVICETABLE entry for the device. This parameter is used in conjunction with an OEM-supplied device manager to permit control of specific DASD and SCSI targets.

/SMSCSI Manager Support

This parameter indicates that this unit must be supported by the IBM- supplied SCSI device manager (OS2SCSI.DMD). If this parameter is not specified, the default setting is to permit SCSI device manager support. If this parameter is negated, the adapter device driver must set the UF_ NOSCSI_SUPT flag in the UnitFlags field of the DEVICETABLE entry for the device. This parameter is used in conjunction with an OEM-supplied device manager to permit control of specific non-DASD and non-SCSI targets.

/IIgnore Adapter

This parameter indicates that adapter device driver should treat the indicated adapter as an uninstalled adapter. The purpose of this parameter is to allow third party software to manage an entire adapter that would normally be managed by the adapter device driver. When specified, the driver must not create a device table entry for the indicated adapter.

/HCWEnable Hardware Write Caching

This parameter is used to control adapter-implemented deferred-write caching for those adapters that support it. If this parameter is not specified, this feature must be enabled. If this parameter is negated, deferred write caching must be disabled on the specified units. Host adapters that do not implement on-board caching, or that do not have direct control over the operation of the cache, must ignore this parameter if specified.

/HCREnable Hardware Read Caching

This parameter is used to control adapter-implemented Read caching for those adapters that support it. If this parameter is not specified, this feature must be enabled. If this parameter is negated, Read caching must be disabled on the specified units. Host adapters that do not implement on -board caching, or do not have direct control over the operation of the cache, must ignore this parameter if specified.

d,d...SCSI Embedded Target ID

The above parameters can be followed by a colon (:) with a list of SCSI target IDs, separated by commas. The logical unit number (LUN) for the specified SCSI target is presumed to be 0.

(d,d),(d,d)...SCSI Target/LUN ID

The above parameters can be followed by a colon (:) with a list of SCSI target/LUN pairs in parentheses.