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Re: SSD's and many edits of a single file

On Monday 09 April 2018 06:18:18 songbird wrote:

> Gene Heskett wrote:
> > Greetings folks;
> >
> > Updodate Wheezy, realtime kernel because machine is running
> > linuxcnc.
> >
> > Editor is geany and file is left open in the editor, and reloaded
> > into linuxcnc as changes are made to the file, and saved but not
> > closed.
> >
> > And eventually the updates made to the file are not actually saved,
> > geany does not report an error and does say success by changing the
> > filename font from red which tells me its been modified, back to
> > black in the window top border, but does not actually update the
> > file on the disk, and the only fix seems to be a reboot.
> >
> > Is this a known fault with some SSD's? Or???
>   i'm not familiar with geany or linuxcnc...  any options
> in geany for save interval?

I think 2 minutes.
>   what kind of file system? 

ext4 w/journaling on.
>   what are the mount options 


> in fstab?
UUID=54273d27-b48f-4a73-9b4d-d3cd13c6ba79 /             ext4 
errors=remount-ro 0        1

>type of SSD?
kernel: [    3.648318] scsi 0:0:0:0: Direct-Access     ATA      SPCC 
Solid State V3.7 PQ: 0 ANSI: 5

Cheap on sale special from newegg. Lots quicker than spinning rust. 
Currently 28% used ack df.

Thanks songbird.
>   a sync once in a while like other poster recommended
> may be a help as it would also clear out any waiting io
> but i'm not sure how much that may interfere with the
> realtime aspects if you have some large chunks waiting.
I can only guess.  These files are generally not long, 100 lines or so if 
I write it but if generated by a code generator, which has no knowledge 
of the looping abilities of linuxcnc's RS-274-D translator, could make a 
40 meg file out of what should be less than 100 properly constructed 
lines of gcode.

>   i've used ionice for some things to make sure they
> don't interfere on an older system with limited
> capacity.

The heart of linuxcnc runs on one core of a multicore cpu, and something 
like ionice would probably get locked out of that playpen and have no 
effect. Any effect would probably encourage it to wreck an otherwise 
purty part. It, LinuxCNC, supplies the motor signals to drive the 
machine to sub-micron accuracy, but to do that it has to be able to 
slice time into nanoseconds.

> my current machine is a screamer in comparison 
> so i've not had to do that.

Most of this stuff isn't the latest and greatest.  Old Dell's, or Atom 
powered shoeboxes even. What matters is how steady a heartbeat it can 
maintain when a beat of the heart might be needed every 25 nanoseconds, 
and the atoms are the fastest kid in town for that. The biggest machine 
is a 1500 lb lathe, and its being run by an r-pi-3b using mesa 
interfaceing cards. Might be the only one on the planet.

>   songbird

Thanks songbird.

Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>