Sometimes computers just crash - try using error-correcting RAM?

I quote: "It’s a well-documented fact that RAM in modern computers is susceptible to occasional random bit flips due to various sources of noise, most commonly high-energy cosmic rays. By some estimates, you can even expect error rates as high as one error per 4GB of RAM per day! Many servers these days have ECC RAM, which uses extra bits to store error-correcting codes that let them correct most bit errors, but ECC RAM is still fairly rare in desktops, and unheard-of in laptops." from http://blog.ksplice.com/2010/06/attack-of-the-cosmic-rays/

...

hello,

i need help to understand a major problem i had today.

i'm unsing a old computer for a project, running ubuntu linux 10.04, with a presonus FP10 fire wire soundcard with jack. everything was running fine for weeks when we worked on this project. i boot this computer 3 days ago, start pd and everything was working wey well for all rehearsal. (i did not close pd since)

the problem i've experience is that pd freeze during the performance.

(fortunately, it was 10 000 Km away from where i'm living so i have no friend on the audience) This is my 1st unexpected pd freeze (when i'm not on edit mode) since i begin using pd, 11 years ago. i'm running pd vanilla with almost no externals thanks to Murphy's law, it occur in performance, and not in rehearsal.

worst of all : i don't know what is the problem, and can't make things work again.

So, the 1st thing i could imagine is a hardware problem, since the software was tested for month. (This patch work for weeks without closing pd, and this pd installation run for 8 month for an installation).

fact are :

• after rebooting the computer/soundcard etc, jack start and works
• audacity can connect to jack.
• pd crash on start-up if started with jack.
• i do not change anything about pd
• i did not physically touch the computer for the last 10 minutes before

the freeze (everything is automatized)

• this computer is not connected to internet, i did not do any update

since it was stable.

• the soundcard works OK on an other computer on osX.

i'll use another computer for tomorrow performance, and i'll have more time to understand the problem when i'll be back home, however i would really appreciate to understand as soon as possible what could cause a huge problem like what i experience today.

So, with that mail i share my shame with you, but i also really apreciate to have some pointer about what to test in order to understand the problem. Why pd can't connect to jack anymore, since jack work and noting was change about pd? and why this occure during a live performance...

thanks for your consideration,

cheers Cyrille  (sad)

---

Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list

---

Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list

hello,

thanks all for your answer.

I'm now back home, and (thanks to Murphy's law), the problem can't be reproduced.

I noticed a bad (physical) Fire wire connection on the cable after the performance, but now it is ok. maybe my audio buffer was too small and any other computer activity could break the connection between pd and jack (but not between audacity and jack)

so the only valid hypothesis i can find is :

• too small buffer for jack configuration
• bad pd implementation of jack
• automatic script in ubuntu that start in bad timing (friday 19h30)
• bad priority between pd and ubuntu script

it's just discouraging that thing worked for 60h straight and crash during the 20 min performance.

The only lesson i can find is that "with computer, you can't prove things are working, you can only prove that things don't work".

did anyone ever experience a slow down due to ubuntu automatic script that should run on the background? how to easily disable them? (cron?)

thanks, Cyrille

Le 09/07/2011 22:31, Hans-Christoph Steiner a écrit :

Well, you have an amazing track record, so I wouldn't sweat too much. Hopefully the rest of the performances go smoothly.

Random freezes are often caused by bad memory, that sounds like the most likely cause here. It can just affect a single program if its only a small part of the memory that is bad. running memtest for a while might find something. If its not bad memory, it could be some other bad hardware. If its a dusty old computer, it would be worth while to blow all the dust out, and re-seat the cards and the RAM.

.hc

On Jul 8, 2011, at 12:57 PM, cyrille henry wrote:

...

hello,

i need help to understand a major problem i had today.

i'm unsing a old computer for a project, running ubuntu linux 10.04, with a presonus FP10 fire wire soundcard with jack. everything was running fine for weeks when we worked on this project. i boot this computer 3 days ago, start pd and everything was working wey well for all rehearsal. (i did not close pd since)

the problem i've experience is that pd freeze during the performance.

(fortunately, it was 10 000 Km away from where i'm living so i have no friend on the audience) This is my 1st unexpected pd freeze (when i'm not on edit mode) since i begin using pd, 11 years ago. i'm running pd vanilla with almost no externals thanks to Murphy's law, it occur in performance, and not in rehearsal. worst of all : i don't know what is the problem, and can't make things work again.

So, the 1st thing i could imagine is a hardware problem, since the software was tested for month. (This patch work for weeks without closing pd, and this pd installation run for 8 month for an installation).

fact are :

• after rebooting the computer/soundcard etc, jack start and works
• audacity can connect to jack.
• pd crash on start-up if started with jack.
• i do not change anything about pd
• i did not physically touch the computer for the last 10 minutes before the freeze (everything is automatized)
• this computer is not connected to internet, i did not do any update since it was stable.
• the soundcard works OK on an other computer on osX.

i'll use another computer for tomorrow performance, and i'll have more time to understand the problem when i'll be back home, however i would really appreciate to understand as soon as possible what could cause a huge problem like what i experience today.

So, with that mail i share my shame with you, but i also really apreciate to have some pointer about what to test in order to understand the problem. Why pd can't connect to jack anymore, since jack work and noting was change about pd? and why this occure during a live performance...

thanks for your consideration,

cheers Cyrille (sad)

---

Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list

---

I spent 33 years and four months in active military service and during that period I spent most of my time as a high class muscle man for Big Business, for Wall Street and the bankers. - General Smedley Butler

---

Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list

Like I said I have been frustrated with jack and pd crashes, especially during a show, sorry that happened to you. I think though it is settling down again in 11, that whole pulseaudio stuff made things overly complicated for no reason. I have had issues with ffado & alsa, sometimes jack fires right up, sometimes I have to run it from command line first. I can never tell, but once it's up and running I no touch.

On 7/13/11 5:56 AM, "cyrille henry" ch@chnry.net wrote:

hello,

thanks all for your answer.

I'm now back home, and (thanks to Murphy's law), the problem can't be reproduced.

I noticed a bad (physical) Fire wire connection on the cable after the performance, but now it is ok. maybe my audio buffer was too small and any other computer activity could break the connection between pd and jack (but not between audacity and jack)

so the only valid hypothesis i can find is :

• too small buffer for jack configuration
• bad pd implementation of jack
• automatic script in ubuntu that start in bad timing (friday 19h30)
• bad priority between pd and ubuntu script

it's just discouraging that thing worked for 60h straight and crash during the 20 min performance.

The only lesson i can find is that "with computer, you can't prove things are working, you can only prove that things don't work".

did anyone ever experience a slow down due to ubuntu automatic script that should run on the background? how to easily disable them? (cron?)

thanks, Cyrille

Le 09/07/2011 22:31, Hans-Christoph Steiner a écrit :

...

Well, you have an amazing track record, so I wouldn't sweat too much. Hopefully the rest of the performances go smoothly.

Random freezes are often caused by bad memory, that sounds like the most likely cause here. It can just affect a single program if its only a small part of the memory that is bad. running memtest for a while might find something. If its not bad memory, it could be some other bad hardware. If its a dusty old computer, it would be worth while to blow all the dust out, and re-seat the cards and the RAM.

.hc

On Jul 8, 2011, at 12:57 PM, cyrille henry wrote:

...

hello,

i need help to understand a major problem i had today.

i'm unsing a old computer for a project, running ubuntu linux 10.04, with a presonus FP10 fire wire soundcard with jack. everything was running fine for weeks when we worked on this project. i boot this computer 3 days ago, start pd and everything was working wey well for all rehearsal. (i did not close pd since)

the problem i've experience is that pd freeze during the performance.

(fortunately, it was 10 000 Km away from where i'm living so i have no friend on the audience) This is my 1st unexpected pd freeze (when i'm not on edit mode) since i begin using pd, 11 years ago. i'm running pd vanilla with almost no externals thanks to Murphy's law, it occur in performance, and not in rehearsal. worst of all : i don't know what is the problem, and can't make things work again.

So, the 1st thing i could imagine is a hardware problem, since the software was tested for month. (This patch work for weeks without closing pd, and this pd installation run for 8 month for an installation).

fact are :

• after rebooting the computer/soundcard etc, jack start and works
• audacity can connect to jack.
• pd crash on start-up if started with jack.
• i do not change anything about pd
• i did not physically touch the computer for the last 10 minutes

before the freeze (everything is automatized)

• this computer is not connected to internet, i did not do any update

since it was stable.

• the soundcard works OK on an other computer on osX.

i'll use another computer for tomorrow performance, and i'll have more time to understand the problem when i'll be back home, however i would really appreciate to understand as soon as possible what could cause a huge problem like what i experience today.

So, with that mail i share my shame with you, but i also really apreciate to have some pointer about what to test in order to understand the problem. Why pd can't connect to jack anymore, since jack work and noting was change about pd? and why this occure during a live performance...

thanks for your consideration,

cheers Cyrille (sad)

---

Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list

---

---

I spent 33 years and four months in active military service and during that period I spent most of my time as a high class muscle man for Big Business, for Wall Street and the bankers. - General Smedley Butler

---

Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list

---

Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list

Hi Cyrille,

désolé pour toi, c'est super vexant ce genre de crash.

cyrille henry wrote:

did anyone ever experience a slow down due to ubuntu automatic script that should run on the background? how to easily disable them? (cron?)

You could set up a runlevel for performance, that runs only the necessary daemons : udev, jack, dbus. No syslog/ssh/avahi/cron/at/cups/acpid/ftp/networkmanager/bluez/whatever... Also you can run a minimalistic X session, with screensaver/dpms/screnblanking disabled and a lightweight window manager.

Hello,

thanks for this suggestion.

Yes, i could spend my time to optimized ubuntu to be more real-time. or i could use an optimized OS for real time stuf. i could install a dual boot or something like this.

But i don't like this solution. mainly because it's an endless work that have to be done every time i change computer. and also because i use lot's of computer that are not mine. and because my computer is dedicated to lot's of different task, i don't want to reboot to use pd.

so i prefer starting pd with a script that stopall unwanted stuff, and start them when i close pd.

so, i made a script like this :

gksudo stop atd gksudo stop cron pasuspender -- pd -noprefs -noautopatch -lib Gem -mididev 1,2,3 -listdev -r 48000 gksudo start atd gksudo start cron

i don't know if is enough, did anyone already made something like this?

thanks Cyrille

Le 13/07/2011 17:33, Charles Goyard a écrit :

Hi Cyrille,

désolé pour toi, c'est super vexant ce genre de crash.

cyrille henry wrote:

...

did anyone ever experience a slow down due to ubuntu automatic script that should run on the background? how to easily disable them? (cron?)

You could set up a runlevel for performance, that runs only the necessary daemons : udev, jack, dbus. No syslog/ssh/avahi/cron/at/cups/acpid/ftp/networkmanager/bluez/whatever... Also you can run a minimalistic X session, with screensaver/dpms/screnblanking disabled and a lightweight window manager.

---

Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list

To me it sounds like maybe in performance you had better bass speakers hooked to your installation that could have shook the firewire connector/cable so much that it dropped connection?

I would pull the cable once while running to see if the effect is similar ;)

-- buZz

On Fri, 15 Jul 2011, Charles Goyard wrote:

my pd startup script has: xset -dpms xset s 0 xset s off exec pdextended -font-size 12 $@

oubliez pas d'éteindre gnome-screensaver ou xscreensaver ou équivalent...

| Mathieu Bouchard ---- tél: +1.514.383.3801 ---- Villeray, Montréal, QC