Avago Technologies LSI53C1010 - Manual (Page 188)

8-2 Writing Device Drivers with SCRIPTS
Figure 8.1 The Role of the SCSI Device Drivers
The device driver itself contains two layers, illustrated in Figure 8.2 . The
top layer is the operating system interface. It accepts and interprets I/O
requests from the host operating system. These requests may vary,
depending on the type and vendor of the SCSI device. The formatted
requests are passed to the hardware interface, or lower layer of the
driver. The operating system interface must also schedule SCSI bus
accesses when more than one device is active. It schedules the I/O
requests and tracks the completed and outstanding I/Os based on status
passed back from the hardware interface. The SCRIPTS program is
compiled with the driver program and is loaded into host memory when
the device driver program starts.
Application Application Application
SCSI Device SCSI Device SCSI Device
Host Operating
SCRIPTS Processor
System
Device Driver