lkml.org 
[lkml]   [1997]   [Sep]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: safe file systems
Date
From
--------
> > Also, your writes have to be very strictly ordered. Some intelligent IO
> > subsystems will reorder your write operations on you, which I guess could
> > cause lots of really obscure hard to track down funnies if you were unaware
> > of you IO doing this.
>
> SCSI itself has flags to stop that happening. We don't appear to have any way
> right now to mark a request ordered let alone tell the scsi layer to tell
> the card to order it.

IDE doesn't have this problem as long as there is no write cacheing enabled
on the drive itseslf. SCSI can get around the problem by disabling tagged
queueing (as an immediate fix), or by adding an ordered tag flag for
commands on tagged queueing devices. However, to truly gaurantee ordered
writes on SCSI you would have to disable drive write cacheing here as well.

--
*****************************************************************************
* Doug Ledford * Unix, Novell, Dos, Windows 3.x, *
* dledford@dialnet.net 873-DIAL * WfW, Windows 95 & NT Technician *
* PPP access $14.95/month *****************************************
* Springfield, MO and surrounding * Usenet news, e-mail and shell account.*
* communities. Sign-up online at * Web page creation and hosting, other *
* 873-9000 V.34 * services available, call for info. *
*****************************************************************************



\
 
 \ /
  Last update: 2005-03-22 13:40    [W:0.097 / U:0.708 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site