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[Solved} 4.30 FileSize() on a RAM disk
Posted: Fri Jan 16, 2009 1:37 pm
by infratec
Hi together,
I tried to communicate between 2 programs and I use files to do this.
I simply check if a specific file exits and than I delete it.
For the check I use the FileSize() procedure as suggested.
On the normal filesystem (ext3) it works.
To avoid many harddisk accesses I installed a ramdisk with
mount -t tmpfs tmpfs /tmp/ramdisk -o size=64k,mode=01777
The disks works. I can read and write to the disk.
But FileSize("/tmp/ramdisk/test") hangs.
Any idea ???
Best regards,
Bernd
Posted: Fri Jan 16, 2009 1:47 pm
by Thalius
hmm just as a tought - are the permissions correctly set ( eg filesize needs +x iirc. ) ?
Posted: Fri Jan 16, 2009 1:52 pm
by infratec
Thanks for the fast response.
But why to hell needs FileSize() execution rights on the file?
So I never can use this function on a 644 file ???
But that's not true.
Because if I try it on /tmp/test which is ext3 it works.
Bernd
Posted: Fri Jan 16, 2009 7:41 pm
by flaith
hi,
i tried the same way under Debian etch but inside mnt directory :
Code: Select all
flaith@wooky:/mnt$ sudo mkdir ramdisk
flaith@wooky:/mnt$ sudo mount -t tmpfs tmpfs /mnt/ramdisk/ -o size=64k,mode=01777
flaith@wooky:/mnt$ cd ramdisk/
flaith@wooky:/mnt/ramdisk$ vi test.txt
Put everything you want inside "test.txt"
With Pb a
Code: Select all
Debug FileSize("/mnt/ramdisk/test.txt")
gives 22
so it works
Posted: Fri Jan 16, 2009 11:36 pm
by Thalius
the x part was just guessed. so it just needs read rights - had not too much time but in my case i had the wrong permissions set on the dir inside mnt while accessing from a non sudo'ed user ... :roll: -- clearly sometimes a day working with windows can hurt your thinking lol
Posted: Sat Jan 17, 2009 12:30 pm
by infratec
Now I'm at home and I checked it with my Kubuntu 8.10 installation.
Result:
FileSize() works correct!
I have an other problem:
Directly behind the filesize check I try to delete the file in an endless loop.
And that is my problem.
At work I can't see this, because the target PC has only 800x600 screen resolution,
and than I can not read the PureBASIC Menu and output: it is to small.
I have to check this now.
As normal user I can not delete a file from user root, but it has 666 as rights.
So it should be possible.
Bernd
Posted: Sat Jan 17, 2009 12:55 pm
by infratec
Hi ,
PROBLEM SOLVED !
It was the mount command!
I set the sticky bit, that was my fault.
With the sticky bit on a directory, only the owner can do a delete,
even when the rights are 666 or 777.
And when I tried it in /tmp, I didn't recognize that kubuntu also has the sticky bit on the
/tmp directory!
(I think on SuSE /tmp has no sticky bit set)
So:
If you want to use a RAM disk as information exchange directory, where the files should be fully accessible, use mode=0777 and not mode=01777
Best regards and thanks,
Bernd