Very Computer

in short:
I have an external scanner, an internal harddisk and an internal
streamer
on my SCSI-Bus. When I scan and write to tape at the same time, both
processes hang up after a few seconds before they exit with error
messages
after 15 minutes.
What is wrong with my configuration?

in long:
1) Scanner
- HP ScanJet IIcx / C2500A
- Active Terminator in 25 pin slot
- external cable in 50 pin slot

2) External Cable
- 2 m long
- 50 pin

3) Host Adapter
- Ultra SCSI Adaptec AHA-2940AU
- SCSI Select Output:
Adaptec AHA-2940AU SCSISelect(TM) Utility v1.30
AHA-2940AU at Bus:Device 00:0Fh

Configuration:
SCSI Bus Interface Definitions
  Host Adapter SCSI ID            7
  SCSI Parity Checking            Enabled
  Host Adapter SCSI Termination   Automatic
BIOS Information
  Interrupt (IRQ) Channel         03
  I/O Port Address                F800h

SCSI Device Configuration:
SCSI Device ID             #0  #1  #2  #3  #4  #5  #6  #7
Initiate Sync Negotiation  yes yes yes yes yes yes yes yes
Enable Ultra SCSI Speed    no  no  no  no  yes no  yes no
Maximum Sync Transfer Rate 10  10  10  10  20  10  20  10
Enable Disconnection       yes yes yes yes yes yes yes yes

Options Listed Below Have NO EFFECT if the BIOS is Disabled
Send Start Unit Command    no  no  no  no  no  no  no  no
BIOS Multiple LUN Support  no  no  no  no  no  no  no  no
Include in BIOS Scan       yes yes yes yes yes yes yes yes

Select SCSI Disk and press <Enter>
SCSI ID #0: No device
SCSI ID #1: No device
SCSI ID #2: No device
SCSI ID #3: HP       C1537A
SCSI ID #4: IBM      DDRS-39130
SCSI ID #5: HP       C2500A
SCSI ID #6: No device
SCSI ID #7: AHA-2940AU

4) Internal Cable
- 50 pin
- 72 cm
- Streamer 47 cm from Host Adapter in middle of cable
- Harddisk 72 cm from Host Adapter at end of cable

5) Streamer
- HP C1554A (according to label on device), C1537A (according to
diagnostic
  messages)
- 4 mm DDS3 tapes
- dip switches: 3: off, 1,2,4,5,6,7,8: on
- TERM PWR: Jumper set

6) Harddisk
- IBM DDRS-39130
- Jumpers:
1 SPARE (50 PIN)
  ID BIT 3
  (FOR WIDE)
2 ID BIT 2   -> Jumper set
3 ID BIT 1
4 ID BIT 0
5 ENABLE     -> Jumper set
  AUTO SPIN
6 SCSI TERM  -> Jumper set
  ON
7 DISABLE
  UNIT ATTN
8 TI SYNC NEGO
9 AUTO START
  DELAY
10 DELAY START
   6/12
11 DISABLE
   PARITY
12 LED OUT

7) Linux diagnostics:
- dmesg:
(scsi0) <Adaptec AHA-2940A Ultra SCSI host adapter> found at PCI 0/15/0
(scsi0) Narrow Channel, SCSI ID=7, 3/255 SCBs
(scsi0) Cables present (Int-50 YES, Ext-50 YES)
(scsi0) Downloading sequencer code... 422 instructions downloaded
scsi0 : Adaptec AHA274x/284x/294x (EISA/VLB/PCI-Fast SCSI) 5.1.31/3.2.4
       <Adaptec AHA-2940A Ultra SCSI host adapter>
scsi : 1 host.
(scsi0:0:3:0) Synchronous at 10.0 Mbyte/sec, offset 15.
  Vendor: HP        Model: C1537A            Rev: L708
  Type:   Sequential-Access                  ANSI SCSI revision: 02
Detected scsi tape st0 at scsi0, channel 0, id 3, lun 0
(scsi0:0:4:0) Synchronous at 20.0 Mbyte/sec, offset 15.
  Vendor: IBM       Model: DDRS-39130        Rev: S97B
  Type:   Direct-Access                      ANSI SCSI revision: 02
Detected scsi disk sda at scsi0, channel 0, id 4, lun 0
  Vendor: HP        Model: C2500A            Rev: 3332
  Type:   Processor                          ANSI SCSI revision: 02
SCSI device sda: hdwr sector= 512 bytes. Sectors= 17850000 [8715 MB]
[8.7 GB]
 sda:
sda1

- /proc/scsi/scsi:
Host: scsi0 Channel: 00 Id: 03 Lun: 00
  Vendor: HP       Model: C1537A           Rev: L708
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 04 Lun: 00
  Vendor: IBM      Model: DDRS-39130       Rev: S97B
  Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 05 Lun: 00
  Vendor: HP       Model: C2500A           Rev: 3332
  Type:   Processor                        ANSI SCSI revision: 02

- /proc/scsi/aic7xxx/0:
Adaptec AIC7xxx driver version: 5.1.31/3.2.4
Compile Options:
  TCQ Enabled By Default : Disabled
  AIC7XXX_PROC_STATS     : Disabled
  AIC7XXX_RESET_DELAY    : 5

Adapter Configuration:
           SCSI Adapter: Adaptec AHA-2940A Ultra SCSI host adapter
                           Ultra Narrow Controller at PCI 0/15/0
    PCI MMAPed I/O Base: 0xfedff000
 Adapter SEEPROM Config: SEEPROM found and used.
      Adaptec SCSI BIOS: Enabled
                    IRQ: 3
                   SCBs: Active 0, Max Active 1,
                         Allocated 15, HW 3, Page 255
             Interrupts: 81
      BIOS Control Word: 0x10b6
   Adapter Control Word: 0x005b
   Extended Translation: Enabled
Disconnect Enable Flags: 0x00ff
     Ultra Enable Flags: 0x0010
 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:
(scsi0:0:3:0)
  Device using Narrow/Sync transfers at 10.0 MByte/sec, offset 15
  Transinfo settings: current(25/15/0/0), goal(25/15/0/0),
user(25/15/0/0)
  Total transfers 0 (0 reads and 0 writes)
(scsi0:0:4:0)
  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(12/15/0/0)
  Total transfers 2 (2 reads and 0 writes)
(scsi0:0:5:0)
  Device using Narrow/Async transfers.
  Transinfo settings: current(0/0/0/0), goal(255/0/0/0), user(25/15/0/0)
  Total transfers 0 (0 reads and 0
writes)

- /var/log/messages (after parallel commands: copy file from sda to st0,
  scan (saving to hda)):
Feb  8 00:27:46 host1 kernel: (scsi0:0:3:0) No active SCB for
reconnecting targe
t - Issuing BUS DEVICE RESET.
Feb  8 00:27:46 host1 kernel: (scsi0:0:3:0)       SAVED_TCL=0x30,
ARG_1=0x4, SEQ
ADDR=0x101
Feb  8 00:28:19 host1 kernel: scsi : aborting command due to timeout :
pid 18320
6, scsi0, channel 0, id 4, lun 0 Write (10) 00 00 08 00 5f 00 00 08 00
Feb  8 00:28:49 host1 kernel: scsi : aborting command due to timeout :
pid 18320
6, scsi0, channel 0, id 4, lun 0 Write (10) 00 00 08 00 5f 00 00 08 00
Feb  8 00:29:49 host1 last message repeated 2 times
Feb  8 00:30:49 host1 last message repeated 2 times
Feb  8 00:31:49 host1 last message repeated 2 times
Feb  8 00:32:49 host1 last message repeated 2 times
Feb  8 00:33:49 host1 last message repeated 2 times
Feb  8 00:34:49 host1 last message repeated 2 times
Feb  8 00:35:49 host1 last message repeated 2 times
Feb  8 00:36:49 host1 last message repeated 2 times
Feb  8 00:37:19 host1 kernel: scsi : aborting command due to timeout :
pid 18320
Feb  8 00:37:49 host1 kernel: scsi : aborting command due to timeout :
pid 183206, scsi0, channel 0, id 4, lun 0 Write (10) 00 00 08 00 5f 00
00 08 00
Feb  8 00:38:19 host1 kernel: scsi : aborting command due to timeout :
pid 183206, scsi0, channel 0, id 4, lun 0 Write (10) 00 00 08 00 5f 00
00 08 00
Feb  8 00:39:19 host1 last message repeated 2 times
Feb  8 00:40:19 host1 last message repeated 2 times
Feb  8 00:41:19 host1 last message repeated 2 times
Feb  8 00:42:19 host1 last message repeated 2 times
Feb  8 00:42:46 host1 kernel: scsi : aborting command due to timeout :
pid 183202, scsi0, channel 0, id 3, lun 0 Write (6) 00 00 10 00 00
Feb  8 00:42:48 host1 kernel: SCSI host 0 abort (pid 183202) timed out -
resetting
Feb  8 00:42:48 host1 kernel: SCSI bus is being reset for host 0 channel
0.
Feb  8 00:42:51 host1 kernel: (scsi0:0:3:0) Synchronous at 8.0
Mbyte/sec, offset 15.
Feb  8 00:42:51 host1 kernel: (scsi0:0:4:0) Synchronous at 20.0
Mbyte/sec, offset 15.
Feb  8 00:42:51 host1 kernel: st0: Error with sense data: [valid=0] Info
fld=0x0, Current st09:00: sense key Unit Attention
Feb  8 00:42:51 host1 kernel: Additional sense indicates Power on,
reset, or bus device reset occurred

your configuration seems to be ok (termination and so on). What does
happen if you do large data transfers on the harddisk while using the
scanner ?? I am not a friend of using scanners, zip drives,... at the
same SCSI controller together with hardisks. Maybe you could get a very
cheap controller for the scanner.

Bye,
Bernd

Quote:> I am not a friend of using scanners, zip drives,... at the
> same SCSI controller together with hardisks.

Quote:>..................
> Host: scsi0 Channel: 00 Id: 05 Lun: 00
>   Vendor: HP       Model: C2500A           Rev: 3332
>   Type:   Processor                        ANSI SCSI revision: 02

I wouldn't put a scanner on the same SCSI bus as hard disks or tape
drives for two reasons:

1. Most SCSI scanners have a 25-pin SCSI connector which IMO is bad. The
remaining 25 lines in the SCSI spec are ground lines and they are there
for a reason. They become critical when you have high speed devices on
the bus like hard disks. I simply prefer to isolate any 25-pin device on
its own bus.

2. A number of SCSI scanners do not support SCSI disconnect feature. As
a result, they can lock the bus up for significant amount of time while
they move the scanner head across the scan bed. This will cause timeouts
on SCSI operations on other devices. This may be what you are seeing.

Hope this helps.

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Khalid Aziz                             Linux Development Laboratory
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DISCLAIMER: I express my opinions only. My employers have nothing to do
                        with my opinions.

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Khalid Aziz

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