Help needed!

[Feng Peirong]

Hi there,

I have a RedHat 6.2 system with 1 IDE disk and 2 SCSI disks. The IDE
disk was bought after I found that the system on SCSI was unstable. 
When reading files (especially large files) on the SCSI disks, the 
output was always changed for unknown reason. For example, when 
computing the md5sum of a large file, say redhat-6.2-srpms.iso, the 
result is different every time!!!

How can I fix this problem?


PROBLEM:

####################################################################
[root at nashua /root]# cd /mnt/sdb5
[root at nashua sdb5]# ll redhat-6.2-srpms.iso 
-rw-r--r--    1 root     root     594044928 Jul  3 11:30
redhat-6.2-srpms.iso
[root at nashua sdb5]# md5sum < redhat-6.2-srpms.iso 
9d94fde9d7d5c9fe2d1c24f21cc7aae0  -
[root at nashua sdb5]# md5sum < redhat-6.2-srpms.iso 
76a196912b411285d605f2aca5fbf832  -
[root at nashua sdb5]# md5sum < redhat-6.2-srpms.iso 
fc73234ed3ab57e896c5153025e7f965  -


SYSTEM INFORMATION:

RedHat 6.2
Pentium II 233MHz
Kernel 2.2.16

SCSI INFORMATION:

################################################################
[root at nashua sdb5]# ll /proc/scsi
total 0
dr-xr-xr-x    2 root     root            0 Jul  3 12:20 aic7xxx/
-rw-r--r--    1 root     root            0 Jul  3 14:01 scsi
[root at nashua sdb5]# cat /proc/scsi/scsi 
Attached devices: 
Host: scsi0 Channel: 00 Id: 00 Lun: 00
  Vendor: SEAGATE  Model: ST34501N         Rev: 0018
  Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 01 Lun: 00
  Vendor: SEAGATE  Model: ST318436LW       Rev: 0004
  Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi0 Channel: 00 Id: 05 Lun: 00
  Vendor: YAMAHA   Model: CRW4260          Rev: 1.0h
  Type:   CD-ROM                           ANSI SCSI revision: 02
[root at nashua sdb5]# ll /proc/scsi/aic7xxx/
total 0
-rw-r--r--    1 root     root            0 Jul  3 14:02 0
[root at nashua sdb5]# cat /proc/scsi/aic7xxx/0
Adaptec AIC7xxx driver version: 5.1.30/3.2.4
Compile Options:
  TCQ Enabled By Default : Disabled
  AIC7XXX_PROC_STATS     : Enabled
  AIC7XXX_RESET_DELAY    : 5

Adapter Configuration:
           SCSI Adapter: Adaptec AIC-7880 Ultra SCSI host adapter
                           Ultra Wide Controller at PCI 0/8/0
    PCI MMAPed I/O Base: 0xe8000000
 Adapter SEEPROM Config: SEEPROM found and used.
      Adaptec SCSI BIOS: Enabled
                    IRQ: 10
                   SCBs: Active 0, Max Active 1,
                         Allocated 15, HW 16, Page 255
             Interrupts: 122865
      BIOS Control Word: 0x18b6
   Adapter Control Word: 0x005e
   Extended Translation: Enabled
Disconnect Enable Flags: 0xffff
     Ultra Enable Flags: 0x0003
 Tag Queue Enable Flags: 0x0000
Ordered Queue Tag Flags: 0x0000
Default Tag Queue Depth: 8
    Tagged Queue By Device array for aic7xxx host instance 0:
      {255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255}
    Actual queue depth per device for aic7xxx host instance 0:
      {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}

Statistics:

(scsi0:0:0:0)
  Device using Narrow/Sync transfers at 20.0 MByte/sec, offset 15
  Transinfo settings: current(12/15/0/0), goal(12/15/0/0),
user(12/15/1/0)
  Total transfers 229 (229 reads and 0 writes)
             < 2K      2K+     4K+     8K+    16K+    32K+    64K+  
128K+
   Reads:     229       0       0       0       0       0       0      
0
  Writes:       0       0       0       0       0       0       0      
0


(scsi0:0:1:0)
  Device using Wide/Sync transfers at 40.0 MByte/sec, offset 8
  Transinfo settings: current(12/8/1/0), goal(12/8/1/0), user(12/15/1/0)
  Total transfers 122548 (101895 reads and 20653 writes)
             < 2K      2K+     4K+     8K+    16K+    32K+    64K+  
128K+
   Reads:       7       0   14051     274     590    1152   85821      
0
  Writes:       0       0    1821    1102     410     103   17217      
0


(scsi0:0:5:0)
  Device using Narrow/Async transfers.
  Transinfo settings: current(0/0/0/0), goal(255/0/0/0), user(12/15/1/0)
  Total transfers 0 (0 reads and 0 writes)
             < 2K      2K+     4K+     8K+    16K+    32K+    64K+  
128K+
   Reads:       0       0       0       0       0       0       0      
0
  Writes:       0       0       0       0       0       0       0      
0


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