usbscsi, libgphoto2 & access

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usbscsi, libgphoto2 & access

Damon Lynch
Hi Marcus,

The venerable Nikon D100 uses the usbscsi interface. Can more than one process access the camera simultaneously when its connected using usbscsi? Or does the usbscsi interface present the same limitation as the PTP/MTP interface, i.e. only one process may access the device at a time?

As an aside, I don't know if it's a known characteristic or not, but a Nikon D800, there are no storage descriptions returned by libgphoto2. At least that was the case with one user; I don't know if it's a widespread phenomena with the D800.

Best,
Damon

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Re: usbscsi, libgphoto2 & access

Marcus Meissner
Hi,

On Tue, Jun 06, 2017 at 03:02:40PM -0500, Damon Lynch wrote:
> Hi Marcus,
>
> The venerable Nikon D100 uses the usbscsi interface. Can more than one
> process access the camera simultaneously when its connected using usbscsi?
> Or does the usbscsi interface present the same limitation as the PTP/MTP
> interface, i.e. only one process may access the device at a time?

I was not aware of the D100 going over usbscsi... I have it listed here as PTP over USB?

Does it speak PTP?

In general it will most likely be single program access.
 
> As an aside, I don't know if it's a known characteristic or not, but a
> Nikon D800, there are no storage descriptions returned by libgphoto2. At
> least that was the case with one user; I don't know if it's a widespread
> phenomena with the D800.

What storage description specifically? Got with what API / cmdline?

It does not seem to be common, I have not heard about that.

Ciao, Marcus

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Re: usbscsi, libgphoto2 & access

Damon Lynch


On Thu, Jun 8, 2017 at 2:50 AM, Marcus Meissner <[hidden email]> wrote:
Hi,

On Tue, Jun 06, 2017 at 03:02:40PM -0500, Damon Lynch wrote:
> Hi Marcus,
>
> The venerable Nikon D100 uses the usbscsi interface. Can more than one
> process access the camera simultaneously when its connected using usbscsi?
> Or does the usbscsi interface present the same limitation as the PTP/MTP
> interface, i.e. only one process may access the device at a time?

I was not aware of the D100 going over usbscsi... I have it listed here as PTP over USB?

Does it speak PTP?

I have no idea. I'll ask the user who uses that camera. I'll also ask him if gPhoto2 can access the camera while it is mounted in his file browser using the usbscsi interface.


In general it will most likely be single program access.

> As an aside, I don't know if it's a known characteristic or not, but a
> Nikon D800, there are no storage descriptions returned by libgphoto2. At
> least that was the case with one user; I don't know if it's a widespread
> phenomena with the D800.

What storage description specifically? Got with what API / cmdline?

I found this problem of the missing storage description because my application (Rapid Photo Downloader, which uses Jim Easterbrook's python bindings) collects storage info using the API, and it was getting an empty result for storageinfo_description. Here is some gPhoto2 output, from the command line:

$ gphoto2 --storage-info
[Storage 0]                                                                  
label=NIKON D800  [Slot 1]
basedir=/store_00010001
access=2 Nur Lesen und Bilder löschen
type=4 Entfernbarer RAM
fstype=4 Kamera Struktur (DCIM)
totalcapacity=7878464 KB
free=7393472 KB
freeimages=1604
[Storage 1]
label=NIKON D800  [Slot 2]
basedir=/store_00020001
access=2 Nur Lesen und Bilder löschen
type=4 Entfernbarer RAM
fstype=4 Kamera Struktur (DCIM)
totalcapacity=31248384 KB
free=13976416 KB
freeimages=179 


Best,
Damon

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Re: usbscsi, libgphoto2 & access

Marcus Meissner-4
On Thu, Jun 08, 2017 at 03:03:35AM -0500, Damon Lynch wrote:

> On Thu, Jun 8, 2017 at 2:50 AM, Marcus Meissner <[hidden email]> wrote:
>
> > Hi,
> >
> > On Tue, Jun 06, 2017 at 03:02:40PM -0500, Damon Lynch wrote:
> > > Hi Marcus,
> > >
> > > The venerable Nikon D100 uses the usbscsi interface. Can more than one
> > > process access the camera simultaneously when its connected using
> > usbscsi?
> > > Or does the usbscsi interface present the same limitation as the PTP/MTP
> > > interface, i.e. only one process may access the device at a time?
> >
> > I was not aware of the D100 going over usbscsi... I have it listed here as
> > PTP over USB?
> >
> > Does it speak PTP?
> >
>
> I have no idea. I'll ask the user who uses that camera. I'll also ask him
> if gPhoto2 can access the camera while it is mounted in his file browser
> using the usbscsi interface.
 
Some more greps later ... it might be talking in "sierra" mode over USBSCSI, yes.



 

> > In general it will most likely be single program access.
> >
> > > As an aside, I don't know if it's a known characteristic or not, but a
> > > Nikon D800, there are no storage descriptions returned by libgphoto2. At
> > > least that was the case with one user; I don't know if it's a widespread
> > > phenomena with the D800.
> >
> > What storage description specifically? Got with what API / cmdline?
> >
>
> I found this problem of the missing storage description because my
> application (Rapid Photo Downloader, which uses Jim Easterbrook's python
> bindings) collects storage info using the API, and it was getting an empty
> result for storageinfo_description. Here is some gPhoto2 output, from the
> command line:

It is still not clear.

> $ gphoto2 --storage-info
> [Storage 0]
>
> label=NIKON D800  [Slot 1]
> basedir=/store_00010001
> access=2 Nur Lesen und Bilder löschen
> type=4 Entfernbarer RAM
> fstype=4 Kamera Struktur (DCIM)
> totalcapacity=7878464 KB
> free=7393472 KB
> freeimages=1604
> [Storage 1]
> label=NIKON D800  [Slot 2]
> basedir=/store_00020001
> access=2 Nur Lesen und Bilder löschen
> type=4 Entfernbarer RAM
> fstype=4 Kamera Struktur (DCIM)
> totalcapacity=31248384 KB
> free=13976416 KB
> freeimages=179

If the description is empty, it will not get reported... the software should handle it, the GP_STORAGEINFO_DESCRIPTION
will not be set then.

Ciao, Marcus

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