On 7 Mar 2006 at 9:42, Silviu Marin-Caea wrote:
On Monday 06 March 2006 14:47, s.schmidt@avm.de wrote:
Even though people might do realtime DSP things in user space with Linux and soft modems might work pretty well in userspace, in the case of Fax G3 an extremely short latency is required.
So basically we have to choose between:
1. keeping a stable open source kernel and sticking to the principles that got Linux where it is now
and
2. Fax G3
Umm...
Hi! Active FAX cards would be a proper solution. However as it has to be cheap, the I/O cards hardly do anything (compare to GDI printers, winmodems, cheap SCSI HBAs, AC97 codecs), and the software (CPU) instead has to do the work. This requires fast CPUs and tight coupling of CPU and hardware. Multiple emulation layers with cooperative scheduling won't do in many cases. So the user has the alternative to spend real money for real devices, or get poor functionality cheap. In former times when buying hardware, you got full specifications from the vendor, because the hardware was the value you paid for. These days, you license some software, and the hardware is mostly just a dongle that makes sure the software doesn't run on anybody else's computer. As the hardware is cheap, and the needed software (well, it's cheap to distribute as well) was expensive to develop, "hardware vendors" don't want to make the software available for competitors (we know, China can make everything much cheaper). ITU is another thing: There's no public fax specification available, so no hobbyist can try to write a fax protocol driver (unless paying significant $$ for the specs). Probably ITU directly forbids writing any well-documented open source fax driver (as comments in the source would explain the protocol most likely). The only free lunch is that you cook yourself it seems ;-) Just some thoughts, Regards, Ulrich