Corrupted files on Boot up

QNX Newsgroups (Archives) qdn.public.qnx4
1

I’m hoping you can help me out with this problem we are experiencing
with file corruption.
I was hoping you could tell me how files become Fragmented or Corrupted? And
if its part of our shut down procedure.

We had an instance where we Exit the program, then turn the power off on
the
unit. We waited about 30 seconds, then booted the system back up. We then
tried to copy files over to another directory when we received. Cannot copy
file Corrupted. We then tried to remove the file, and the same error
occurred.

I’m hoping you can help me out.

Thanks

Vince Aldrich
Neptec Design Group
613-599-7603 ext . 522

2

Previously, Vinnie wrote in qdn.public.qnx4:

I’m hoping you can help me out with this problem we are experiencing
with file corruption.
I was hoping you could tell me how files become Fragmented or Corrupted? And
if its part of our shut down procedure.

We had an instance where we Exit the program, then turn the power off on
the
unit. We waited about 30 seconds, then booted the system back up. We then
tried to copy files over to another directory when we received. Cannot copy
file Corrupted. We then tried to remove the file, and the same error
occurred.

Make sure you’re running “chkfsys” in your sysinit file. This will clean up some file system junk in the event of a sudden power loss. Other than that, you may want to try 1 of the following:

  1. Run “shutdown” or its equivalent before removing power or rebooting the device.

  2. Modify your call to Fsys with the -c and -d options. -c will let you reduce the file cache size. -d is the delay applied to asynchronous writes. Lowering these parameters may reduce overall filesystem performance, but it will be more fault-tolerant.

HTH,

  • Pete
3

You might want to run “sin files” before shutting down to see
if you’ve missed something.

Mitchell Schoenbrun --------- maschoen@pobox.com

4

I guess I was alittle vague on the question.

I just wanted to know how Files became fragmented or corrupted?

Thanks


Mitchell Schoenbrun wrote in message …

You might want to run “sin files” before shutting down to see
if you’ve missed something.

Mitchell Schoenbrun --------- > maschoen@pobox.com

5

Fragmented and corrupted are two quite different phenomena.
A file becomes fragmented when its allocated space is insufficient
and the “next” block in not free. If the disk isn’t full, Fsys
will provide blocks and add to list of extents. ls -hx will show
extent/fragmentation info.

Corruption means that there is an inconsistency between /.bitmap,
/.inodes and/or one or more directory entries. This usually is
caused by a power down or reboot when written files are not
completely flushed to disk, but can also be caused by a faulty
drive, memory, etc.

Read the docs. They go into fair detail about the disk layout,
so if what I said above doesn’t make much sense you will become
enlightened. See Installation & Configuration->Disk & File Recovery.
There is a section about the file system structure.


Vinnie wrote:

I guess I was alittle vague on the question.

I just wanted to know how Files became fragmented or corrupted?

Thanks

Mitchell Schoenbrun wrote in message …
You might want to run “sin files” before shutting down to see
if you’ve missed something.

Mitchell Schoenbrun --------- > maschoen@pobox.com