VHBA module
~~~~~~~~~~~


Table of Contents:
~~~~~~~~~~~~~~~~~~

1. Introduction
2. Requirements
3. Installation
4. Debugging
5. Contact information


1. Introduction
~~~~~~~~~~~~~~~

This is VHBA (Virtual SCSI Host Bus adapter), a Linux kernel module which
acts as a low-level SCSI driver and which provides the SCSI layer with a
virtual SCSI adapter which can have multiple virtual devices. It is part of
the cdemu suite, a free, GPL CD/DVD-ROM device emulator for linux.
It is written in C.

Its typical use in the CDEmu software suite is to provide virtual devices
that emulates real SCSI Optical (CD-ROM) devices. It works in cooperation with
the CDEmu daemon and libMirage to emulate an Optical (CD-ROM) drive and disc
with information contained in a disc image. For your information, a disc image
is just a copy of the information stored on an actual disc.


2. Requirements:
~~~~~~~~~~~~~~~~

 - Kernel development headers >= 3.0


3. Installation:
~~~~~~~~~~~~~~~~

Please read the INSTALL file.


4. Debugging:
~~~~~~~~~~~~~

Should you experience problems with the kernel module, there may be a need to
collect information for a bugreport so you can submit to the developers.
Like other kernel modules VHBA makes use of a feature called dynamic debugging.
This essentially toggles extra debug information on/off during runtime.

There are several ways to do this, one way is when you load the module:

$ modprobe vhba dyndbg==pflmt

If you need to manually enable debugging, which might be the case if you
compile the module yourself and load it with insmod, first identify where your
debugfs is mounted, then send your enable command to the control node.

$ mount -t debugfs
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
$ echo -n "module vhba +pflmt" > /sys/kernel/debug/dynamic_debug/control

Once dynamic debug is enabled you may try to provoke a crash or go about your
normal routine. You can then inspect the debug information like so:

$ dmesg

You can collect this information into a text file with:

$ dmesg > dmesg.log

Which you can attach to any bugreport you send the developers. For more
information consult "The Linux kernel user’s and administrator’s guide".
It should be included in the Linux kernel Documentation package.


5. Contact information:
~~~~~~~~~~~~~~~~~~~~~~~

CDEmu project's web page: http://cdemu.sourceforge.net
CDEmu project's mailing list: cdemu-devel@lists.sourceforge.net

Author can be directly contacted via e-mail address listed in AUTHORS file.

