Using the writeread[x] procedures – HP Integrity NonStop H-Series User Manual
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Interfacing With the Open SCSI I/O Process (IOP)
Using the WRITEREAD[X] Procedures
sync-depth
This parameter is optional. The Open SCSI IOP does not support the sync-ID
mechanism. Even if a nonzero value is assigned to
sync-depth
, the IOP treats it
as 0.
options
This parameter is not handled directly by the Open SCSI IOP.
seq-buffer-id
The Open SCSI IOP does not perform sequential block buffering.
seq-buffer-len
The Open SCSI IOP does not perform sequential block buffering.
primary-processhandle
The Open SCSI IOP does not directly support the
primary-processhandle
parameter.
Using the WRITEREAD[X] Procedures
The Guardian WRITEREAD[X] procedures write data to a device from a buffer in the
application process and then wait for data to be transferred back (read) from the
device. The data from the read operation is returned in the same buffer as that used for
the write operation.
WRITEREAD is intended for use with 16-bit addresses, and WRITEREAD[X] is
intended for use with 32-bit extended addresses. Therefore, the data buffer for the
WRITEREAD[X] procedures can be in either the caller’s stack segment or any
extended data segment. For simplicity, in the remainder of this subsection, this
procedure call is referred to as WRITEREAD.
The syntax of the WRITEREAD procedure call is:
filenum
When an application or driver successfully opens a SCSI device, a file-number
value
is returned. This value should be passed to the
filenum
parameter when
you call WRITEREAD to send SCSI commands to the device.
CALL WRITEREAD [x] (filenum !
i
,buffer !
i,o
,write-count !
i
,read-count !
i
,[count-read] !
o
,[tag]); !
i