Disk simulator driver

Disk simulator driver

[Sean Bruno]

Is there a project/driver that would take a disk/file/lvm partition as
an argument(/dev/sda, /tmp/my_big_file.bin /dev/Mapper/MYLVMPART eg.)
and then create a new /dev entry that could be read/written to as though
it were a disk?

I think I want to look at sg, but I wasn't sure if that is what I want.

Just poking around for fun and education.

Sean

Re: Disk simulator driver

[Matt Domsch]

On Sun, Oct 29, 2006 at 12:19:19PM -0800, Sean Bruno wrote:
> Is there a project/driver that would take a disk/file/lvm partition as
> an argument(/dev/sda, /tmp/my_big_file.bin /dev/Mapper/MYLVMPART eg.)
> and then create a new /dev entry that could be read/written to as though
> it were a disk?
> 
> I think I want to look at sg, but I wasn't sure if that is what I want.
> 
> Just poking around for fun and education.
> 
> Sean

You want something different than losetup and /dev/loop ?
e.g. something you can issue disk-like ioctls to?

-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

Re: Disk simulator driver

[Sean Bruno]

On Sun, 2006-10-29 at 17:02 -0600, Matt Domsch wrote:
> On Sun, Oct 29, 2006 at 12:19:19PM -0800, Sean Bruno wrote:
> > Is there a project/driver that would take a disk/file/lvm partition as
> > an argument(/dev/sda, /tmp/my_big_file.bin /dev/Mapper/MYLVMPART eg.)
> > and then create a new /dev entry that could be read/written to as though
> > it were a disk?
> > 
> > I think I want to look at sg, but I wasn't sure if that is what I want.
> > 
> > Just poking around for fun and education.
> > 
> > Sean
> 
> You want something different than losetup and /dev/loop ?
> e.g. something you can issue disk-like ioctls to?
> 
Precisely.  I am interested in capturing the data that would be sent to
the device and copying it somewhere before it is written to the disk.
Kind of like the way target mode drivers accept a file/disk as a target
for their operations.

Sean

Re: Disk simulator driver

[Aboo Valappil]

Hi Sean,

I have posted some messages before with the subject "About SG Elements 
of request_buffer" and "SCSITAP, Virtual SCSI HBA and user space SCSI 
initiators". Can you please read them and tell me what you think?
I have exactly what you wanted, and other people in the email group 
either said it is already there or not seems to be very much interested.

Basically, i built to impliment some user space SCSI engines and 
initiators. If you want i can email you a working copy of it where you 
can present the normal files as disks.

Aboo

Sean Bruno wrote:
> On Sun, 2006-10-29 at 17:02 -0600, Matt Domsch wrote:
>   
>> On Sun, Oct 29, 2006 at 12:19:19PM -0800, Sean Bruno wrote:
>>     
>>> Is there a project/driver that would take a disk/file/lvm partition as
>>> an argument(/dev/sda, /tmp/my_big_file.bin /dev/Mapper/MYLVMPART eg.)
>>> and then create a new /dev entry that could be read/written to as though
>>> it were a disk?
>>>
>>> I think I want to look at sg, but I wasn't sure if that is what I want.
>>>
>>> Just poking around for fun and education.
>>>
>>> Sean
>>>       
>> You want something different than losetup and /dev/loop ?
>> e.g. something you can issue disk-like ioctls to?
>>
>>     
> Precisely.  I am interested in capturing the data that would be sent to
> the device and copying it somewhere before it is written to the disk.
> Kind of like the way target mode drivers accept a file/disk as a target
> for their operations.
>
> Sean
>
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>   

Re: Disk simulator driver

[Sean Bruno]

On Mon, 2006-10-30 at 23:42 +1100, Aboo Valappil wrote:
> Hi Sean,
> 
> I have posted some messages before with the subject "About SG Elements 
> of request_buffer" and "SCSITAP, Virtual SCSI HBA and user space SCSI 
> initiators". Can you please read them and tell me what you think?
> I have exactly what you wanted, and other people in the email group 
> either said it is already there or not seems to be very much interested.
> 
> Basically, i built to impliment some user space SCSI engines and 
> initiators. If you want i can email you a working copy of it where you 
> can present the normal files as disks.
> 
> Aboo

It would be very good if you could send me the code you have written.

I would like to see where your code hooks into the /dev/ tree and how it
handles write requests.


Sean