[gphoto-devel] 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

[Damon Lynch]

Post by Damon Lynch
Hi,

Post by 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?

Post by Damon Lynch
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.

Post by Damon Lynch
In general it will most likely be single program access.

Post by Damon Lynch
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

[Marcus Meissner]

Post by Damon Lynch

Post by Damon Lynch
Hi,

Post by 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?

Post by Damon Lynch
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.

Post by Damon Lynch

Post by Damon Lynch
In general it will most likely be single program access.

Post by Damon Lynch
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

It is still not clear.

Post by Damon Lynch
$ 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