Browse Prior Art Database

Unconditional Installation of SCSI Device Drivers

IP.com Disclosure Number: IPCOM000111865D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 109K

Publishing Venue

IBM

Related People

Feriozi, DT: AUTHOR

Abstract

Disclosed is the unconditional installation of a device driver using the information stored in BIOS to determine the kind and number of SCSI devices present in the system. If an option flag used by this installation feature is set, the device driver installs itself, and installs all registered devices, even if the devices do not respond to commands.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 51% of the total text.

Unconditional Installation of SCSI Device Drivers

      Disclosed is the unconditional installation of a device driver
using the information stored in BIOS to determine the kind and number
of SCSI devices present in the system.  If an option flag used by
this installation feature is set, the device driver installs itself,
and installs all registered devices, even if the devices do not
respond to commands.

      Without this feature, device drivers do not install if no
associated devices are found during the initialization of the device
driver.  For external devices, the most common reason a device is not
found is that it has not been powered on at this time.  When this
occurs, the user must either turn the device on and reboot the system
to repeat the initialization process, or the user must continue to
operate the system without using the device.  This alternative may
cause additional problems to occur if drive letter assignments have
changed due to the missing device.  Batch files depending on drive
letter knowledge may fail.  These problems are exacerbated if this
condition occurs in a server.

      Machine configuration information is maintained in NVRAM for
use at power-on by the POST (Power-On Self-Test) process.  When the
system is started, the POST test determines the current
configuration, which is compared to the expected configuration for
which information is stored.  If a discrepancy is found, the user is
advised to run the Setup Utility to install new devices, or to test
possibly defective devices.

      However, the unconditional installation feature of the Setup
Utility provides an option to enable or to disable presence checking
of individual SCSI devices.  With presence checking enabled, if a
device listed in the stored configuration data does not respond to
the POST test, an error is reported.  With presence checking
disabled, such an error is not reported, so the device is registered
with BIOS, to be available for allocation and access through the BIOS
interfaces, even though the device is actually not present.  When
presence checking is disabled by the user, POST and BIOS lay
necessary groundwork for the unconditional installation of the device
by the device driver, which determines system configuration from the
information stored in BIOS.  At this point, the device driver can
install devices not responding to commands, without verifying the
operation of the device before installation.  The user indicates, by
an option flag, that the device driver is to install all devices
registered in BIOS, and to install itself, even if these devices do
not respond to the usual SCSI device inquiry or to other commands.

      The device driver initialization code sets the device-installed
flag to true or false when a device driver is initially loaded into
the system.  If the device is found to be present at initialization
time, the device- installed flag is set to true, resulting in the
traditional...