9.7. Boot considerations

PnP hosts are required to assign SCSI IDs in a consistent and repeatable manner through power cycles or resets using the algorithm specified in section 6.4.3, so long as the SCSI bus configuration remains static. Non-static environments, such as physically removing or powering down a device prior to a boot cycle, may affect drive ID assignment, which can lead to no-boot situations. Resolution of this issue is beyond the scope of this specification. The issue requires system level solutions possibly affecting the BIOS and the operating system.

The long-term solution to non-static configuration environments is PnP system extensions enabling the end user to select the boot device on multiple-device systems. Until such extensions are defined and implemented, the no-boot condition, which can occur in legacy systems today, may also occur in PnP systems. In both cases, the correct boot device may be recognized by adjusting the SCSI IDs through host adapter utilities or changing the device default ID. This is an interim solution which will be replaced when a broader PnP system solution is defined.