OS X (lack of) tape support, was Re: [HECnet] tape image manipulations...

[Clem Cole]

below (in blue)


On Sun, Feb 16, 2014 at 11:00 PM, Dave McGuire <mcguire at neurotica.com> wrote:
On 02/16/2014 10:54 PM, John Wilson wrote:>
> Does it have any kind of raw SCSI interface, like /dev/sg* on Linux?
*BSD, Linux, Darwin, Mach, Tru64, and SVR4/Solaris all used a different ways to splice SCSI support into the kernel I/O system and user namespace [actually I liked the way Tru64 did the best - thank you Fred if you are listening].   


  
> It'd be easy to work around the lack of real tape drivers if so ...

   I think maybe it did not, but it's been awhile since I messed with OS X.
  
If you note when you run "system info" the parallel SCSI kernel sub-system is still listed in the I/O section.   Like Dave, it's been a while since I played with the Mach/Darwin kernel, but last I checked some of the pieces seem to be still there, i.e. a complete eradication of SCSI was not done by Apple.    But at the time, I realized it was more than I wanted to mess with it.

I have had some of the Darwin sources on my file server, and I'll try to take a peek later to see what is there.

The issue I ran into is that since you are pulling the >>kernel<< support in, the support for the driver has to be in the key of that kernel which takes some messing around.   The good news is from the user space all of them supported many of the same ioctl's and in particular used the *BSD tape interface - so I agree that in theory it should not be too hard.

Clem