On 06/08/2010 20:48, Petr Jakeš wrote:
Is there some method how to check/detect presence of the device on the
bus much faster (say 1-2 seconds)?
Can, for example, the DS9097U RS-232 Serial Port Adapter
<http://www.maxim-ic.com/products/ibutton/products/readers.cfm#rs232>
or the DS9490R USB Port Adapter
<http://www.maxim-ic.com/products/ibutton/products/readers.cfm#rs232>
improve the speed of detection?
Or is there some SW trick (buffer etc..) how get results faster?
Please see the following results from the lead developer's tests:
---
Just did some quick tests, using a large passive network:
The first number is the number of devices.
LINK (serial)
p...@paul-desktop:~/owfs$ time (/opt/owfs/bin/owdir | wc -l)
112
real 0m5.021s
user 0m0.008s
sys 0m0.000s
DS9097U (serial)
p...@paul-desktop:~/owfs$ time (/opt/owfs/bin/owdir | wc -l)
113
real 0m6.297s
user 0m0.004s
sys 0m0.004s
DS9097 (passive circuit, serial)
p...@paul-desktop:~/owfs$ time (/opt/owfs/bin/owdir | wc -l)
112
real 0m55.456s
user 0m0.000s
sys 0m0.008s
This was with bus traffic turned on, so the noisier DS9097 get
penalized. Still, they all find the same number of devices, except the
DS9097U has an 09 chip in the adapter.
For comparison,
USB
p...@paul-desktop:~/owfs$ time (/opt/owfs/bin/owdir | wc -l)
113
real 0m0.016s
user 0m0.000s
sys 0m0.004s
p...@paul-desktop:~/owfs$ time (/opt/owfs/bin/owdir /uncached | wc -l)
112
real 0m1.940s
user 0m0.004s
sys 0m0.004s
Cached (the first one) cheats because the bus gets enumerated on startup
for USB, but /uncached should be a valid comparison.
And finally,
LinkUSB
p...@paul-desktop:~/owfs$ time (/opt/owfs/bin/owdir | wc -l)
112
real 0m4.919s
user 0m0.000s
sys 0m0.004s
-----------------------------
So, in terms of efficiency, the adapters that have better Search
algorythms do better (USB > LINK > DS9097U >> DS9097)
---
USB adaptors are definately the fastest. Hope this helps.
Chris
Chris
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