The store blog from EverythingHerePlus.com answers questions regarding U111M compatibility with Mac OS X in Store EverythingHerePlus.com: U111-M Q&A, Compatibility with Mac OS X?. Of interest is the OpenBSD work around testing we did. U111M units with the most current firmware (1.05 above) work just fine with OpenBSD, with the exception of PCMCIA PC Card hot-swapping. As long as the card is inserted in the U111-M prior to connecting, the OpenBSD kernel recognizes it. In fact, there's no need to reboot between PCMCIA PC Card exchanges. Unplugging and plugging in the U111M on the USB bus is all that's necessary to recognize a new card.
Using OpenBSD, we were able to read, write, format, create binary images from, and write binary images to PCMCIA PC Card SRAM and ATA Flash. These capabilities, using just standard command line Unix utilities, are features once exclusively part of expensive, proprietary, Windows software packages. Now, using the U111-M with OpenBSD or Linux provides important low level features often needed with equipment from Honeywell, Canon, Epson, and others.
EverythingHerePlus.com will soon have detailed instructions for these operations.