Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Programming
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Databases
Mail Systems
openSolaris
Eclipse Documentation
Techotopia.com
Virtuatopia.com
Answertopia.com

How To Guides
Virtualization
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Windows
Problem Solutions
Privacy Policy

  




 

 

Writing Device Drivers
Previous Next

Support for Queuing

For a definition of tagged queuing, refer to the SCSI-2 specification. To support tagged queuing, first check the scsi_options flag SCSI_OPTIONS_TAG to see whether tagged queuing is enabled globally. Next, check to see whether the target is a SCSI-2 device and whether the target has tagged queuing enabled. If these conditions are all true, attempt to enable tagged queuing by using scsi_ifsetcap(9F).

If tagged queuing fails, you can attempt to set untagged queuing. In this mode, you submit as many commands as you think necessary or optimal to the host adapter driver. Then the host adapter queues the commands to the target one command at a time, in contrast to tagged queuing. In tagged queuing, the host adapter submits as many commands as possible until the target indicates that the queue is full.

Previous Next

 
 
  Published under the terms fo the Public Documentation License Version 1.01. Design by Interspire