USB Flash Reader on Linux Fedora Core 1

With digital cameras so popular, the USB multi-format card readers are readily available, inexpensive, and supported on Linux.

The memory cards in the reader show up as SCSI disk devices. The digital camera manufacturers have standardized on the MSDOS FAT filesystem, so you can just read and write to the memory card through the reader as if it were a disk drive.

Many USB card readers show up in Linux as a multi-LUN SCSI device. This means that only the first slot is seen by default. You may see the compact-flash slot but not the SmartMedia or MMC slot. To fix this, your Linux kernel needs to scan for the extra LUNs.

For Fedora Core 1, I added the following line to /etc/modules.conf:

options scsi_mod max_scsi_luns=6

as mentioned on the Fedora mailing list. More information is on the Linux flash readers page, or using a USB card reader in Linux.

You can also recompile your kernel with the option “CONFIG_SCSI_MULTI_LUN=y” enabled, or you can add a “max_scsi_luns=6” option at boot time in Grub.


Submitted by amillar on Sat, 2005-01-22 23:48

Polaroid Fun! Flash 640 Digital Camera

Shooting Digital
B&N , Powells

This camera has 640×480 resolution with built-in memory and a serial interface, holding about 16 pictures. There is no USB nor memory card slot.

This camera was designed as Windows-only, with proprietary TWAIN drivers to talk to the camera over the serial port.

Work was done to reverse-engineer the serial protocol for GPhoto 2. It works, and I was able to get pictures from the camera as PPM files using gtkam and the gphoto command-line tool.

In my testing, the colors are slightly different in the gphoto output, compared to the Windows Twain driver output.

The Fun! Flash 640 is different from the PDC-640 and 640SE models. Web references for the Fun Flash 640 are hard to find in 2005. Most searches turn up information about the PDC model. I recommend GPhoto as the main resource for technical details.