Aspi stands for Advanced SCSI Programming Interface which is an application programming interface created by Adaptec, which institutionalises correspondence with a SCSI (Small Computer System Interface) gadget through a typical SCSI gadget driver. ASPI gives a lot of capacities that are normal to any SCSI gadget.
The ASPI administrator programming gives an interface between ASPI modules (gadget drivers or applications with direct SCSI support), a SCSI has a connector, and SCSI gadgets associated with the host connector.
The ASPI director is explicit to the host connector and working framework; its essential job is to extract the host connector points of interest and give a conventional programming interface to SCSI gadgets.
The ASPI for Win32 was intended to expand similarity and rearrange the association of SCSI fringe gadgets like tape, CD-ROM, WORM, magneto-optical, scanners, and different gadgets.
ASPI appears as a character gadget driver. The driver introduces the ASPI director, a gadget named $SCSIMGR. At startup, the ASPI chief surveys the SCSI transport, searching for joined gadgets. A gadget must be turned on before boot-up with the end goal for ASPI to remember it.
The main time you get to the ASPI driver through DOS is the point at which you introduce it. At different occasions, a far call to the ASPI-chief passage point offers access to the ASPI work set. This makes ASPI capacities safe to use from inside a gadget driver or memory-inhabitant program.
Using ASPI requires information of the SCSI direction set and capacities for the gadget you wish to help. Remember that ASPI gives interface capacities, not abnormal state SCSI capacities. The ASPI administrator simply goes information through to the SCSI gadget without changing or investigating it.
The ASPI work set is little, however amazing. A portion of the capacities return data about the driver and condition, while others really speak with the SCSI gadget.
To instate the ASPI director, get a document handle to the ASPI driver by issuing a DOS open call to the $SCSIMGR gadget. Next, use a DOS IOCTL read to acquire the ASPI passage point address.
This is a far location you call to execute any of the ASPI capacities. Finally, close the document handle. You won’t have to get to the driver through DOS once more. Posting One (page 159) represents this means.
All ASPI capacities normally use a SCSI ask for square (SRB). The SRB has a typical 8-byte header for each capacity, containing an ASPI order code (see Table 2), have connector number, and demand banners. The header additionally contains a status byte that the ASPI supervisor uses to restore the result of the ASPI ask.
Capacities that just access the ASPI administrator return right away. Capacities that speak with the SCSI gadget may come back with the status byte set to 0, showing that the demand is still in advancement.
ASPI offers two strategies for deciding if a SCSI ask for has finished: surveying and posting. Surveying, as the name suggests, basically implies occasionally checking the status byte for nonzero esteem. Posting, then again, advises the ASPI supervisor to execute a post-handling routine when the SCSI ask for has finished.
You empower posting by setting the Post bit in the demand banners and passing the location of the daily schedule in the SRB. The ASPI documentation prescribes that applications use surveying, holding posting for gadget drivers or TSR programs, which might be hinder driven.