SCSI Termination |
March, 03, 2003 12:17 PM |
grokking |
I've recently read that one possible reason for unsuccessful Jaguar installs is improper scsi termination. I'm trying to install to an internal 18GB Seagate Barracuda to no avail. Does this particular drive need to be configured in a certain way to work? Does it even have the proper requirements to run Jaguar? Thanks. |
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RE: SCSI Termination |
March, 10, 2003 12:02 PM |
rpertierra |
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Here's what happened. I bought 2 128MB chips for my 7300 that was already running Jaguar and everything was fine. Then I ordered a new hard drive and 2 more 128MB chips and that's when everything went to hell :)) ...next time I'll install one thing at a time. Everything worked perfect in OS 9 but if I tried to install Jaguar on another drive it would either fail before finishing or during boot after the install the screen would freeze and "break into pieces". I thought it was a scsi problem so I reformatted the drive, changed parameters, etc... What finally pointed me to the solution was removing everything from my computer, USB/Firewire, the new drive, and all the memory, then I tried installing Jaguar to an external scsi drive with one of the 128 MB chip at a time. One of them was bad and none of the memory checkers I tried found a problem. What is interesting is that the chip that was bad was one of the original 2 that I ordered. I now have the drive and all four chips (replaced the bad one -- OWC stands by their products) and everything works great. BTW all my memory is interleaved with no problems. |
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RE: SCSI Termination |
March, 06, 2003 4:25 PM |
grokking |
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rpertierra, thanks for the reply. I know it might not be the drive configuration but I'm just gathering all information that I can. I've heard it may be bad RAM, so I'll check that as well. Did your RAM seem to work fine until OSX was installed? Just to clarify, were you able to install OSX but not boot, or could you not even complete the installation process? |
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RE: SCSI Termination - maybe it's not the drive. |
March, 05, 2003 1:51 PM |
rpertierra |
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I have a similar machine to yours except with a Sonnet G4/400 card. I recently ordered an IBM 36GB drive and 2 more 128MB memory chips from OWC and could not install OS X. I thought it was a termination problem. After I tried everything, I removed all my 128MB chips (I had 4) and OS X installed fine. Then I removed all the memory and installed 1 128MB chip at a time until I found one that was bad. What was amazing was that the bad one was not one of the new ones. Apparently the OS X install is a good "memory checker". I was going crazy with termination and it was the memory. The bad chip worked fine when OS X was installed (or so I thought) :) ... In your case it might be termination but who knows! |
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RE: SCSI Termination |
March, 04, 2003 1:57 PM |
tempest |
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By the way, my posts regarding LVD drives is on the internal fast SCSI chain in my 8500. Enabling active termination on the drives does not work properly on all the LVD drives I've tried (Quantum, IBM, Seagate) without the proper adapter. |
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RE: SCSI Termination |
March, 04, 2003 11:54 AM |
grokking |
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Thanks Dwight for the insight. |
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RE: SCSI Termination |
March, 04, 2003 11:42 AM |
earlyd416 |
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Hold on here! The 7300/7600 family uses the CD-ROM to terminate the internal SCSI device chain - when you look it with Apple Profile or the popular SCSI control panel program (was it from ATTO?), the CD-ROM will be in position 7 on the chain. You should be looking to set the jumpers on the drive w/o termination. The big deal with termination is when you have an LVD drive. This type of drive requires Active Termination. The internal SCSI of the 7300/7600 uses passive termination which can be accomplished on the devise, itself. So, what you've been reading about probably is the ATTO UL2D PCI SCSI controller for LVD drives. Bottomline, go download all the docs on your drive from the Seagate website and get smart. Althought I'm not a computer engineer (an aeronautical engineer to be exact), I did sleep once at a Holiday Inn Express. So, that's how I know all this. 8-) --Dwight |
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RE: SCSI Termination |
March, 04, 2003 9:48 AM |
grokking |
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Thanks for all the replies, guys. I will try the suggestions I've gleaned here and report back. |
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RE: SCSI Termination |
March, 04, 2003 3:07 AM |
tempest |
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The SCSI FAQ available on the net demystifies much of the "black magic" associated with SCSI termination. Relevant sections are termination and termination power. |
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RE: SCSI Termination |
March, 04, 2003 2:46 AM |
manuel |
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Sheldon, right IF a device is already terminated on the chain. Normally just the first and last devices should be terminated as Tempest wrote. However I've seen devices like CD-ROMS right in the middle of a chain being terminated and all other devices physically after the CD-ROM didn't required to be terminated (you just need one terminator on the chain). On the opposite, Grokking check your chain if you don't have 2 devices or more on the same chain being already terminated. Terminators are just resistors (jumpers on SCSI devices) and if you don't have the right electrical resistance on the chain you can get into troubles, SCSI devices are more or less tolerant to this and may or may not work, hence the requirement of black magic skills as well ;-) |
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RE: SCSI Termination |
March, 03, 2003 9:29 PM |
sheldonrl |
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This may sound like sour grapes, but I think termination is black magic. If it says terminate, try it. If it dosen't work, unterminate it. Use what ever works. What always seems to be true is that it is always the last physical device on the SCSI chain which must or must not be terminated. |
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RE: SCSI Termination |
March, 03, 2003 8:32 PM |
tempest |
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The first and last _device_ should be terminated. Usually, the first device is the host computer on Macs and it is already terminated. If you terminate the first and last _drive_, it may not work properly or cause flakey behavior. Terminate the last device. Termination applies to the physical position of each device and have nothing to do with their IDs. |
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RE: SCSI Termination |
March, 03, 2003 6:18 PM |
mitch707 |
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Most drive manufactures support pages will have pin-out identification and jumper settings you'll need for setting unit I.D.,termination, etc. You'll need the Mod#. Example: ST118273FC. - mitch |
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RE: SCSI Termination |
March, 03, 2003 5:52 PM |
powderhaus |
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SCSI termination can get confusing but the way it goes it you need to have the 1st and the last drives along the chain terminated and they can not be set to the same binary number there will be a bunch of switches or plastic things with 2 holes it them and you must put one on the spot that says term (if it should be terminated) and then there should be other spots to put the plastic things and if you don't get binary numbers just make sure that you do not have the same combination of plastic things on any drives. if you drive came from OWC there should be a guide to termination with it. Good luck! |
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RE: SCSI Termination |
March, 03, 2003 4:34 PM |
grokking |
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I'm running a 7300 with an XLR8 G4/450 Mach Carrier MPe. 700 RAM. Using onboard SCSI. No stock CD-ROM. It's actually installing onto the drive but won't boot. Sorry, I should have clarified that before. Using the right drivers and initialized properly. I have some posts on the L2 CacheConfig thread below with more details of my problem, but I thought I'd try to get info about possible SCSI problems as well. I've also been told to deinterleave my RAM, which I would rather not do until all else fails. Thanks for any help you can give. |
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RE: SCSI Termination |
March, 03, 2003 1:06 PM |
macman |
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I've been successful with installing on SCSI before. Tell a little more about your config - are you using onboard SCSI or a pci card? Do you have the stock CDROM installed? Also, where in the install is the drive failing? Beware if you do have the stock CDROM installed as these usually have active termination turned on. You may want to disable active termination on the drive and ensure that the CDROM is at the end of the SCSI chain. Other people have had success by attaching the SCSI cable to the slower, external interface on the board. Also, make sure that you have initialized the drive with either Apple's Drive Tools (OS 9 version) or Intech's Hard Disk tools. Stephen |
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