I have just installed/tested linux-2.2.0-pre8.
There seem to be a very old error in
linux/drivers/scsi/sd.c
.
It appears in kernel v2.0.33 and 2.1.128 also.
I've an Adaptec 2940 UW SCSI controller and a IBM DDRS-39130 HD conected to it.
The capacity of the HD is:
9,138,286,080 bytes
8,924,107.500 KB
8,714.949 MB
8.510 GB !!! (remember: 1024 instead of 1000) !!!
The SCSI driver sd.c (linux/drivers/scsi/sd.c) reports:
=== cut ===
SCSI device sda: hdwr sector= 512 bytes. Sectors= 17850000 [8715 MB] [8.7 GB]
=== end cut===
-------------------------------------------------------> !!!!!!! !!!!!!
The 2nd value is wrong!
8,715MB are 8.5GB - and not 8.7GB!!!
This seems not to be a major bug, but it would be nice to see the correct
values at kernel boot of a clean 2.2.0 ;-)
The following diff should explain how to correct the bug:
diff -u --recursive --new-file linux-2.2.0-pre8.orig/drivers/scsi/sd.c
linux-2.2.0-pre8/drivers/scsi/sd.c
=== cut ===
--- linux-2.2.0-pre8.orig/drivers/scsi/sd.c Wed Jan 20 18:05:04 1999
+++ linux-2.2.0-pre8/drivers/scsi/sd.c Wed Jan 20 19:51:31 1999
@@ -1378,7 +1378,7 @@
* Jacques Gelinas ([EMAIL PROTECTED])
*/
int m, mb;
- int sz_quot, sz_rem;
+ /* int sz_quot, sz_rem; not used anymore - calculation was wrong */
int hard_sector = rscsi_disks[i].sector_size;
/* There are 16 minors allocated for each major device */
for (m=i<<4; m<((i+1)<<4); m++){
@@ -1387,12 +1387,25 @@
mb = rscsi_disks[i].capacity / 1024 * hard_sector / 1024;
/* sz = div(m/100, 10); this seems to not be in the libr */
m = (mb + 50) / 100;
+
+ /* This calculated/printed the wrong GB size!
sz_quot = m / 10;
sz_rem = m - (10 * sz_quot);
printk ("SCSI device %s: hdwr sector= %d bytes."
" Sectors= %d [%d MB] [%d.%1d GB]\n",
nbuff, hard_sector, rscsi_disks[i].capacity,
mb, sz_quot, sz_rem);
+ -- end of wrong section */
+ /*
+ * Print whole gigabytes and tenths. Treat tenths as a fixed point
+ * quanitity scaled by 10, rounding up by adding .5 * .1 * 1G = 51.2M
+ * prior to the truncating division.
+ */
+ printk ("SCSI device %s: hdwr sector= %d bytes."
+ " Sectors= %d [%d MB] [%d.%1d GB]\n",
+ nbuff, hard_sector, rscsi_disks[i].capacity,
+ mb, mb / 1024, (mb * 10 + 512) / 1024 % 10);
+
}
if(rscsi_disks[i].sector_size == 2048)
rscsi_disks[i].capacity <<= 2; /* Change into 512 byte sectors */
=== end cut ===
Looking forward for a clean 2.2.0
Niki
---
Niki W. Waibel - Author of the free N64 software emulator TrueReality
-
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