> Bret, you are one of the few people who know how > to write USB software. How did you learn to do it? > Are there any good books on the subject?
It's mostly been trial and error (with a heavy emphasis on the error). My main reading for USB is just the USB specifications. Unfortunately, almost none of the USB hardware is 100% compliant with the specifications (which, believe it or not, Microsoft seems to encourage, at least indirectly). So, in addition to the specifications, I need to occasionally do Internet searches for how problems are handled by others, and also occasionally look at Linux source code. I normally can't use the Linux source code directly, though, since it's written in C instead of ASM and the Linux architecture is completely different than DOS (Linux doesn't have TSR's and doesn't have the same kinds of memory limitations that DOS has). I don't know if you've really ever noticed, but TSR's that are written in high-level languages (like C or Pascal) usually have lots of in-line ASM since high-level languages don't work very well when manipulating hardware. But, the Linux code reveals a lot of experience in what doesn't work and some information about non-compliant or non-standard hardware and where the non-compliance occurs. The main USB-related web page I frequent is: http://janaxelson.com/usb.htm and she (Jan Axelson) has written some USB books, though I've never read them. A lot of the questions on the PORTS Forum have to do with how to get things to work with Windows and are not "general" USB-related as such, but are sometimes still interesting or relevant. _______________________________________________ Freedos-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freedos-user
