I have an external HP SureStore DLT VS80 with a SCSI LVD 68 pin
interface and an external HP SureStore DAT24 with a SCSI Centronics
50 pin Narrow SE interface. The cable for the DAT has a Centronics
connector at one end and a 68 Pin Wide to Narrow terminated
connector at the other. The cable for the DLT has a LVD/SE 68 pin
connector at both ends. I have terminator blocks for both devices.
If I connect the devices thus:
terminator --> DAT --> DLT --> scsi_hostadapter (boot hangs)
Then the system hangs when booting. I can get the system to boot
up form this point by turning off both external tape drives. If I
connect the devices individually then the host boots and the system
can access which ever is attached to the host.
terminator --> DLT --> scsi_hostadapter (boots, device accessible)
terminator --> DAT --> scsi_hostadapter (boots, device accessible)
My question is: Is it possible to daisy-chain these two devices to
the host in manner that permits the system to boot and access both;
and if so, how does one accomplish this?
Regards,
Jim
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On 21/09/05, James B. Byrne <ByrneJB at harte-lyne.ca> wrote:> I have an external HP SureStore DLT VS80 with a SCSI LVD 68 pin > interface and an external HP SureStore DAT24 with a SCSI Centronics > 50 pin Narrow SE interface. The cable for the DAT has a Centronics > connector at one end and a 68 Pin Wide to Narrow terminated > connector at the other. The cable for the DLT has a LVD/SE 68 pin > connector at both ends. I have terminator blocks for both devices. > > If I connect the devices thus: > > terminator --> DAT --> DLT --> scsi_hostadapter (boot hangs) > > Then the system hangs when booting. I can get the system to boot > up form this point by turning off both external tape drives. If I > connect the devices individually then the host boots and the system > can access which ever is attached to the host. > > terminator --> DLT --> scsi_hostadapter (boots, device accessible) > > terminator --> DAT --> scsi_hostadapter (boots, device accessible) > > My question is: Is it possible to daisy-chain these two devices to > the host in manner that permits the system to boot and access both; > and if so, how does one accomplish this?Are you mixing HVD and LVD cabling? What are the SCSI IDs for each of the tape drives? Will.
On Wed, 21 Sep 2005 at 10:49am, James B. Byrne wrote> I have an external HP SureStore DLT VS80 with a SCSI LVD 68 pin > interface and an external HP SureStore DAT24 with a SCSI Centronics > 50 pin Narrow SE interface. The cable for the DAT has a Centronics > connector at one end and a 68 Pin Wide to Narrow terminated > connector at the other. The cable for the DLT has a LVD/SE 68 pin > connector at both ends. I have terminator blocks for both devices.*snip*> My question is: Is it possible to daisy-chain these two devices to > the host in manner that permits the system to boot and access both; > and if so, how does one accomplish this?It should be possible, but it's generally not recommended. Having even one SE device on a LVD chain drags every device on the chain down to SE. In addition to reducing the SCSI bus speed, you're also severely limiting your cable length. To accomplish the mixing, you have to make sure that the wide->narrow converter is *active*, not passive. I don't know that I've ever seen a cable with an active wide->narrow converter. You'll likely have to buy an adapter. And, again, if you go this route, check the standard and make sure you're not over the allowed SE cable length. It's awfully short. Given that you're likely to have to buy an adapter, why not just buy a cheap SE SCSI card instead and have each drive on its own bus? -- Joshua Baker-LePain Department of Biomedical Engineering Duke University