At 3:58 PM -0500 2/7/03, Dan C wrote: >At 02:36 PM -0600 02/07/2003, Jeff Walther wrote: >[snip lotsa great scsi chain examples] >>I think that's enough. > >Oh, I just can't resist. Just to confuse things, here's a chain that >maybe shouldn't work, but it does, electrically... > >T:MB===D1===D2========D3===D4:T=============D5===D6:T > >The gaps between D2 and D3, D4 and D5 being loooong SCSI cables. > >Turns out if the chain is really long, echos can still happen even >when it's terminated at each end properly. Adding a terminated >device into the middle of the chain, such as a JAZ drive (with term >set to on), sometimes fixes things right up! Wierd, but it works. :) > >- Dan. > (shaking confused cat over Mac Bible)
Hi again, ID JUMPERS Well I've set the Micropolis ID at 2 using the long "Option Jumper Block" (took a minute cause the names had shifted from their indicating arrows) but ALSO having figured out the mid-board place where the ID can be set as well (or optionally?) need I set the ID at 2 in both places? There is also a jumper on "Optional Parity Check Option" (PTY) should I leave it on? T-T-TERMINATION Cornfuzed agin. I'm catching on to the fact that the jumpers supply power to the built in terminator pins within the SCSI plug pin bank � whereas I've been thinking of the jumpers as the actual "terminators". So it appears (to me) that two of the pins are "W3" and both "supply +5v to the terminators � and that the other two pins are W2 and W1? Right now there is a jumper on the two W3s, which probably means it is just parked there and that the drive is presently un-terminated. This could explain why, WHEN I had my "probably-terminated" Seagate 2nd from last with the un-terminated Micropolis at the end of the ribbon, that the computer said it was unreadable (and would I like to initialize). Of course I stupidly went for "O.K" probably losing a ton of good piracy :�) � no big deal there though. So anyway, I know that I could make these termination instructions clearer for the next rookie like me � when you help me figure it out, that is. Also in the diagram from this, the best site, a pin is designated 'W2" whereas on the circuit board it is 'W1' ?? Are TWO jumpers necessary on these 4 pins?? Here's the site page from Dan again: http://www.mm.mtu.edu/drives/micropolis/new/3243Config.html Thanks again and again, TT -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
