lkml.org 
[lkml]   [2006]   [Nov]   [2]   [last100]   RSS-feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
Complete thread (EXPERIMENTAL)
/
DateFri, 03 Nov 2006 00:10:20 +0100
FromEric Dumazet <>
SubjectRe: New filesystem for Linux
Digg This
Grzegorz Kulewski a écrit :
Hi,

On Thu, 2 Nov 2006, Mikulas Patocka wrote:
As my PhD thesis, I am designing and writing a filesystem, and it's now in a state that it can be released. You can download it from http://artax.karlin.mff.cuni.cz/~mikulas/spadfs/

"Disk that can atomically write one sector (512 bytes) so that the sector contains either old or new content in case of crash."
Well, maybe I am completly wrong but as far as I understand no disk currently will provide such requirement. Disks can have (after halted write):
- old data,
- new data,
- nothing (unreadable sector - result of not full write and disk internal checksum failute for that sector, happens especially often if you have frequent power outages).


I believe some vendors have such devices. Mikulas called them 'disk', but it's in fact a (disk(s), controler, ram, battery)

Some controlers are even able to write into flash memory the un-written data when/if the battery/power is about to fail. When power goes up, controler can finaly do the writes on disks.


And possibly some broken drives may also return you something that they think is good data but really is not (shouldn't happen since both disks and cables should be protected by checksums, but hey... you can never be absolutely sure especially on very big storages).

So... isn't this making your filesystem a little flawed in design?

Well... even RAM can fail :) In this case isnt linux flawed in design ?

\
ISP Services
Valid XHTML 1.0!\ /
Valid CSS! Last update: 2006-11-02 23:15    [W:1.160 / U:0.290 seconds]
©2003-2005 Jasper Spaans