choosing hardware
07 Apr 2009 08:20 - 07 Apr 2009 16:50 #55
by luminize
choosing hardware was created by luminize
Hi guys,
I've installed EMC/Ubuntu on an old computer (P4, 2,6GHz, 1GB ram, 5 years old) and can't run 'latency-test'. I'm getting some segmentation fault and the keyboard input didn't work anymore.So.....
I dug up an old P3 (667Mhz, 385MB ram, about 8 years old) and latency test ran, but was not very good (max jitter base thread 195712, max jitter servo thread 202572).
For testing and playing around, the P3 works for me now, but i want a good system when i'm going to produce chips.
I've ordered an Mesa 5i20 card (should be here in 2 weeks).
Since every computer you buy is shipped with windows (I'm a windows user, I have to use windows for SolidWorks) and i don't want another OEM windows install, I'm thinking of configuring one.
- Is it worth the trouble to try to get the P4 running (or do you suspect even then the latency is bad, the P3 and P4 are the same brand)
- For a new system, should i look for multi-cores or should i be searching for a single core processor. (If multicores don't add anything, why buy them)
- 64 bit or 32 bit?
- Can the video card be the simpelest (cheapest) version available? or spend 40 euro more for something better.
- Any pitfalls i should know about?
- Is there a big chance on errors in a brand new system?
- What considerations should i take for chosing hardware that is stable and balanced (in respect with the other hardware).
Thanks, Bas
I've installed EMC/Ubuntu on an old computer (P4, 2,6GHz, 1GB ram, 5 years old) and can't run 'latency-test'. I'm getting some segmentation fault and the keyboard input didn't work anymore.
luminize@lumi-P4:~$ latency-test
/etc/init.d/realtime: line 148: 5688 Segmentation fault $INSMOD $MOD
RTAPI: ERROR: could not open shared memory (errno=2)
HAL: ERROR: rtapi init failed
halcmd: hal_init() failed: -9
NOTE: 'rtapi' kernel module must be loaded
RTAPI: ERROR: could not open shared memory (errno=2)
HAL: ERROR: rtapi init failed
halcmd: hal_init() failed: -9
NOTE: 'rtapi' kernel module must be loaded
RTAPI: ERROR: could not open shared memory (errno=2)
HAL: ERROR: rtapi init failed
halcmd: hal_init() failed: -9
NOTE: 'rtapi' kernel module must be loaded
ERROR: Module hal_lib does not exist in /proc/modules
ERROR: Module rtapi does not exist in /proc/modules
ERROR: Module rtai_math does not exist in /proc/modules
ERROR: Module rtai_sem does not exist in /proc/modules
ERROR: Module rtai_fifos does not exist in /proc/modules
ERROR: Module rtai_sched does not exist in /proc/modules
ERROR: Module rtai_hal is in use
luminize@lumi-P4:~$I dug up an old P3 (667Mhz, 385MB ram, about 8 years old) and latency test ran, but was not very good (max jitter base thread 195712, max jitter servo thread 202572).
For testing and playing around, the P3 works for me now, but i want a good system when i'm going to produce chips.
I've ordered an Mesa 5i20 card (should be here in 2 weeks).
Since every computer you buy is shipped with windows (I'm a windows user, I have to use windows for SolidWorks) and i don't want another OEM windows install, I'm thinking of configuring one.
- Is it worth the trouble to try to get the P4 running (or do you suspect even then the latency is bad, the P3 and P4 are the same brand)
- For a new system, should i look for multi-cores or should i be searching for a single core processor. (If multicores don't add anything, why buy them)
- 64 bit or 32 bit?
- Can the video card be the simpelest (cheapest) version available? or spend 40 euro more for something better.
- Any pitfalls i should know about?
- Is there a big chance on errors in a brand new system?
- What considerations should i take for chosing hardware that is stable and balanced (in respect with the other hardware).
Thanks, Bas
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14 Apr 2009 08:19 - 14 Apr 2009 11:28 #87
by alex_joni
Replied by alex_joni on topic Re:choosing hardware
luminize wrote:
Both can be equally bad or good (depending on how much luck you have)
I have an AMD Athlon XP 1600+ which works great (needless to say it's quite old).
Also Intel P3's are known to be pretty good with respect to latency. So are some recent Core 2 Duo's (but the chance it works great/doesn't work at all is more pronounced on these).
Take a look at some submitted numbers: wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Latency-Test
Regards,
Alex
I had a conversation with a guy from a computer store, and his advice was:
Choose a motherboard with an 'older' processor, there could be bugs for the newest processors because when the motherboard was made, they were not yet available.
Also, if something runs in an old P3 or P4, today, anything should run fine on newer systems.
This makes sense to me.
He couldn't tell me if i should choose AMD or INTEL though, Any suggestions?
Bas
Both can be equally bad or good (depending on how much luck you have)
I have an AMD Athlon XP 1600+ which works great (needless to say it's quite old).
Also Intel P3's are known to be pretty good with respect to latency. So are some recent Core 2 Duo's (but the chance it works great/doesn't work at all is more pronounced on these).
Take a look at some submitted numbers: wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Latency-Test
Regards,
Alex
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