who can clearly tell the difference of ioscan -fu and ioscan -fk

[常有慈悲心]

i read the man page again and again,but can't get it clearly.
please help.

[RAC_1 · Accepted solution]

ioscan -fu

-f full listing of devices(give details about class, drive and some other details.)
-u usable device

ioscan -fk

As said above -f stand for full listing.
-k Look in the kernel (do not actullay do a llokup, just list what is there in kernel)

Anil

[Geoff Wild]

Anil has it...

If ioscan -k is used, the kernel I/O system data structures are scanned instead of the actual hardware, and the results are listed.

If ioscan is invoked with the -u option, usable I/O system devices (those with a driver in the kernel that have a logical unit number assigned) are listed.

You can alos use -C for class, like disk, or lan

Rgds...Geoff

[Prashant Zanwar_4]

ioscan -fk shall give you all devices which are attached to your system, claimed by kernel...


while -u will scan and list usable IO system devices for example disks. CD and HBA etc.

Thanks
Prashant

[Victor BERRIDGE]

Hi,
I would add that both options do not rescan the hardware
So you may see with e.g. ioscan -funC disk
all the disks installed since the last hardware scan even though some may not be reachable ( deactivated one HBA or a scsi controller...)
The same is true if you have just added new hardware (disks): They will not show up till a full hardware scan is performed...
All the best
Victor

[常有慈悲心]

according this ,ioscan -u ,find usable device,
but ioscan -k ,find process and memory,
are these device not usable?

[Geoff Wild]

The outputs are very similiar - by usable - it means items like disks, lan, audio...

-k shows those as well as items like system bus adapters, the "target" class, processor.

memory does NOT have a logical unit number assigned - that's why it doesn't show up in a -u

Rgds...Geoff

[Pete Randall]

No, the -k option simply scans the kernel rather than the actual devices. Scanning the devices themselves can take a long time so the -k option simply provides a quick way to run ioscan. The only time you would not want to use -k is when you've recently attached a new device and want to see it.


Pete