> I have the same problem!?
> The write speed is about 400 KB/s but read speed is very low (only 70 KB/s).
Yup. Writes will be done using DMA or programmed I/O if it can. Reads revert
to the software-emulated mode at the moment (due to the brokenness of the
hardware ECP reading code -- this is something I'm attempting to fix, albeit
> But how can I found out if I am using the ECP hardware or only software emulation of ECP?
The difference in speed is usually the best indication. I've only ever
seen around 70 k/s for software-emulated stuff. The best hardware speed
I've seen so far was around 800 k/s in EPP mode (both directions, using the
PARPORT_EPP_FAST flag (PP_SETFLAGS/PP_GETFLAGS for ppdev).
> I heard about a speed of 1 MB/s, how can I reach it?
Dunno. In some cases (zip drive for example) the driver can rely on certain
assumptions, such as the device always being ready to accept data, and a known
amount of data always being available in the reverse direction. The avoidance
of error-checking (timeouts, etc.) really speeds things up in this case.
After getting a digital logic analyser on the parport lines once, it was
discovered that the device was willing to go *much* faster (probably up to
2.5 m/s in ECP), but the PC was restricting it.. We never conclusively
discovered what the cause was (could be any number of things, but probably
related to a crappy (standard) parport). I would hope that some PCI cards
might be able to deliver faster data rates (iirc, warp9 (www.fapo.com) do
some PCI cards, and their chips are really rather good).
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This archive was generated by hypermail 2b29 : Mon May 28 2001 - 06:07:57 EDT