From: erik quanstrom <quanstro@quanstro.net>
To: 9fans@9fans.net
Subject: Re: [9fans] i/o error reading large sata disk
Date: Sat, 5 Apr 2008 23:58:23 -0400 [thread overview]
Message-ID: <ee54f08125cd185f588cbaaa2c09804d@quanstro.net> (raw)
In-Reply-To: <140e7ec30804051950i4efa218fw80de2db93e1cf99b@mail.gmail.com>
> term% cat /dev/sdE0/ctl
> inquiry ST3300831AS
> config 0C5A capabilities 2F00 dma 00550020 dmactl 00000000 rwm 16
> rwmctl 0 lba48always off
> geometry 586072368 512 16383 16 63
> part data 0 586072368
> part plan9 63 293025600
> part plan9.1 293041665 586067265
> term% dd -if /dev/sdE0/plan9 -of /dev/sdE0/plan9.1 -bs 8192 -iseek 16777211
> read: i/o error
i think i see the problem. we're off by one bit.
in your case, i calculate h = 0xf. but since the head shares bits
with the device, there just isn't enough room for a head > 7. i think you
can fix this problem by
(a) setting lba48always on
; echo llba48always on>/dev/sd??/ctl
if this doesn't work, then i'm wrong.
(b) (the proper fix). apply this change to sdata
/n/sources/plan9//sys/src/9/pc/sdata.c:1344,1350 - sdata.c:1344,1350
};
static int
- atageniostart(Drive* drive, vlong lba)
+ atageniostart(Drive* drive, uvlong lba)
{
Ctlr *ctlr;
uchar cmd;
/n/sources/plan9//sys/src/9/pc/sdata.c:1351,1357 - sdata.c:1351,1357
int as, c, cmdport, ctlport, h, len, s, use48;
use48 = 0;
- if((drive->flags&Lba48always) || (lba>>28) || drive->count > 256){
+ if((drive->flags&Lba48always) || (lba>>27) || drive->count > 256){
if(!(drive->flags & Lba48))
return -1;
use48 = 1;
/n/sources/plan9//sys/src/9/pc/sdata.c:1359,1365 - sdata.c:1359,1365
}
else if(drive->dev & Lba){
c = (lba>>8) & 0xFFFF;
- h = (lba>>24) & 0x0F;
+ h = (lba>>24) & 7; /* tautology */
s = lba & 0xFF;
}
there's also a problem with disk > 2GB. but that's not your problem.
- erik
next prev parent reply other threads:[~2008-04-06 3:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-06 2:50 sqweek
2008-04-06 3:58 ` erik quanstrom [this message]
2008-04-06 16:19 ` sqweek
[not found] ` <b0541197023336a814de597a7abcaa66@quanstro.net>
2008-04-14 4:51 ` sqweek
2008-04-22 13:56 ` erik quanstrom
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