Ioscan command

[Amit Jawalkar]

What for "u" option used in ioscan command, I have already gone through the Man page of ioscan but still not clear.

Can anybody help me explain it more clearly?

Thanks in advance.

Regards
Amit jawalkar

[Steven Haywood (SA)]

-u Scan and list usable I/O system devices instead
of the actual hardware. Usable I/O devices are
those having a driver in the kernel and an
assigned instance number. The -d, -C, -I, and
-H options can be used to restrict listings.
The -u option cannot be used with -k.

[Peter Godron]

Amit,
for example, if you have added a brand new type of tape drive, for which there is no driver in the kernel, ioscan may show the device, but will not be able to use it.

ioscan -u will only show you the devices the machine can use. So the difference between the ioscan -u and ioscan would indicate (amongst other things) that a driver may be missing in the kernel.

Hope this answers the initial question.

Please also read:
http://forums1.itrc.hp.com/service/forums/helptips.do?#33 on how to reward any useful answers given to your questions.

[deepakinit]

hai,

amit

-u option in ioscan command is used to list the devices that are in use.(ie) it is used to list the devices that r installed in the system which has the driver in the os kernel

[Raj D.]

Amit,

As mentioned above ,with -u option it will scan the devices with the kernel drivers that have been loaded in the system , and not the actual hardware that is present on the system, Suppose you have a tape device connected in the system but the stape driver is not loaded , so with -u option it will not scan that device. Check # strings /etc/ioconfig to see the kernel device drivers loaded in the system, At boot time this file is read and the information is stored in the io_tree kernel data structure. To scan all the hardware in real time do not use -u or -k option ,and can be filtered it with the specific requirement like disk or tape or fc.(# ioscan -fnC disk , to list all disks with (f)full listing with device number (n) and (C) for Class=disk)

Cheers,
Raj.

[Peter Godron]

Amit,

Could you please complete the thread by awarding points to helpful answers and summarising the solution for you.

This will help resolution of similar problems in the future.

Please see:
http://forums1.itrc.hp.com/service/forums/helptips.do?#33 on how to reward any useful answers given to your questions.

[Reshma Malusare · Accepted solution]

Hi Amit,
Ioscan command with "u" option will scan only devices with their associated drivers present.