To:		Leif Neland <leifn_ERASE@darla.swimsuit.roskildebc.dk>,
cc:	tomppa_ERASE@fidata.fi,
        fabio_ERASE@cesar.unicamp.br, 
        gcrutchr_ERASE@nightflight.com, 
        j_ERASE@uriah.heep.sax.de, 
        jc_ERASE@irbs.com,  
        julian_ERASE@freebsd.org, 
        kuku_ERASE@gilberto.physik.rwth-aachen.de, 
        nikm_ERASE@ixa.net,
        tomppa_ERASE@fidata.fi,
        wilko_ERASE@yedi.iaf.nl, 
        Greg Lehey <grog_ERASE@lemis.com>,
        Julian H. Stacey <jhs@
        Leif Neland <leifn_ERASE@darla.swimsuit.roskildebc.dk>,
	scsi_ERASE@FreeBSD.ORG
bcc:		freebsd-questions_ERASE@FreeBSD.ORG
Subject:	Re: bytes gets substituted on write 
From:		Julian H. Stacey <jhs@

[ Moved from (but bcc'd to) freebsd-questions_ERASE@FreeBSD.ORG ]

Reference:
> From:		Greg Lehey <grog_ERASE@lemis.com> 
> Date:		Wed, 26 Nov 1997 13:10:32 +1030 
> Message-id:	<19971126131032.61824_ERASE@lemis.com> 

Greg Lehey wrote:
> On Wed, Nov 26, 1997 at 01:06:04AM +0100, Leif Neland wrote:
> > Here I go again:
> >
> > When copying a large file, suddenly 8 bytes in a row gets substituted
> > with 0xff!
> > When I repeat the copy, it's the same 8 bytes.
> 
> Where are they in the block?
> 
> > It also happens, when I either use ftp on this machine to get a file
> > or use ftp on another to put the file.
> > System: 486dx33Mhz, 8MB ram, Old Adaptec, 4 scsi's, the one with fbsd
> > is a maxtor "scsi-0".
> 
> Would the controller be a 154[02]A?  People have seen this before.  I
> can't recall, but I seem to think that 8 bytes is about the reconnect
> length for the controller.  Are they located on 8-byte boundaries?
> 
> Try tweaking your controller parameters.  I don't know if this would
> help, but it could help us work out what's wrong here.
> 
> Greg

Hi Leif,
cc Greg et all,

If it's a 1542A let me know !
I have a directory of notes on the 1542a & FreeBSD (see below).
Brief summary of symptoms:
	Intermittent burst of 8 * 0xFF bytes on occasional multiples of
	(I recall) 1or4K boundaries on drives >= sd1 ,
	mainly when multiple devices active (I think).
Others apart from me have seen similar.

I have an A, a B, and a C, but no complaints about the B or C.
If your problem is with a B or C, I have nothing useful to contribute,
in that case I suggest you just discuss with <scsi@freebsd.org>.

If you have an A with problems, please mail me, and also CC the following:
	tomppa_ERASE@fidata.fi,
	fabio_ERASE@cesar.unicamp.br,
	gcrutchr_ERASE@nightflight.com,
        j_ERASE@uriah.heep.sax.de,
	jc_ERASE@irbs.com,
	julian_ERASE@freebsd.org,
        kuku_ERASE@gilberto.physik.rwth-aachen.de,
        nikm_ERASE@ixa.net,
	tomppa_ERASE@fidata.fi,
	wilko_ERASE@yedi.iaf.nl,
	Greg Lehey <grog_ERASE@lemis.com>,
	Julian H. Stacey <jhs@
	Leif Neland <leifn_ERASE@darla.swimsuit.roskildebc.dk>
who all have, or have had an interest in FreeBSD & 1542A scsi cards.

I'm no scsi expert, just someone who's put a lot of time
into observing the 1542A 8 0xFF bytes bug, (& even ripped off cache chips
& replaced, & thrown out a perfectly good 500M drive, all seeking to track 
this down (It'd be cheaper to Axe my 1542A into final submission ;-).

If it's a 1542A card, please read my archive of mail, try my testblock/ & 8f/
& let us know your results, etc.

General data testing tool:
	http://........../~jhs/src/bsd/jhs/bin/public/testblock/
Specific 1542A corrupt data testing search tool (use with find):
	http://.........../~jhs/src/bsd/jhs/bin/public/8f/
Archive of mail (will upload in next days (as of 1997.11.26)):
	http://........./~jhs/1542a/

Julian
--
Julian H. Stacey       jhs@