Re: Sending SCSI commands in Mac OS X
Re: Sending SCSI commands in Mac OS X
- Subject: Re: Sending SCSI commands in Mac OS X
- From: rohan a <email@hidden>
- Date: Thu, 23 Jul 2009 17:23:48 +0530
Will an ioctl() enable me to do this ?
Hence, any SCSI commands on a standalone device can be sent without
the need for a seperate driver?
On 7/23/09, Terry Lambert <email@hidden> wrote:
> Did you go to <http://developer.apple.com> and read the document "SCSI
> Architecture Model Device Interface Guide"?
>
> It states:
>
> "By design, Mac OS X does not allow applications to send SCSI or ATA
> commands to storage devices unless the application developer also provides
> an in-kernel device driver that supports the commands."
>
> One of the intents if this is to allow the driver to model state for such
> coomands such that the state if the device is known to the driver at all
> times.
>
> For standard tape devices, you should not need to write your own driver; if
> you plug the device in, it will show up in /dev, and you can at least issue
> reads, writes, and standard commands, such as causing a rewind, via the
> device file. For non-standard commands, such as you would use to control
> loading and unloading tapes in a tape robot, etc., you will need to write an
> in-kernel driver that knows how to talk to the hardware and subclasses the
> more generic device (i.e. the IOKit model lets you write only the missing
> pieces implementing the missing control commands; you don't write a whole
> driver that implements read/write/etc.).
>
> -- Terry
>
>
> On Jul 23, 2009, at 3:10 AM, rohan a <email@hidden> wrote:
>
> >
> > Also, can ioctl() be used in any way to send SCSI commands to devices?
> >
> > On 7/23/09, rohan a <email@hidden> wrote:
> >
> > > Hello,
> > > I am trying to learn SCSI programming on Mac OS X.
> > > While reading a document "Working with Sam" I read that only INQUIRY
> > > and TEST_UNIT_READY commands can be sent using the IO registry.
> > > Does that mean even sending SCSI Read or Write commands is not
> > > possible without writing a driver for the device?
> > >
> > > So if I need to write a backup/restore tool that backups to SCSI tape
> > > devices, will I also need to write drivers for the tape?
> > >
> > > Thanks
> > >
> > >
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