> Does anyone have any advice on the subject of using > newer, 68-pin SCSI disks in (or with) older Macs having > 50-pin internal and 25-pin external SCSI connectors? > Can they be used at least in some limited way with a > suitable cable or cabinet,
In theory it should work; I'm not sure if there's anything to do with Apple's idea of SCSI that might prevent it. Some of my Sun external hardware says it can be connected to a narrow (50 pin) host adapter. I've also got an SCA adapter which has both 50 and 68 pin interfaces on it. from the comp.periphs.scsi FAQ: QUESTION: Can I connect a WIDE device to my narrow SCSI host adapter? QUESTION: Can I connect a narrow device to my WIDE SCSI host adapter? ANSWER FROM: Gary Field ([EMAIL PROTECTED]) ==== Yes, you just need an appropriate adapter. Most WIDE devices use the 68 pin "P" connector so you need a 68 pin to 50 pin adapter. You do need to make sure that both the upper byte and lower byte of the bus will be properly terminated though. Some adapters provide a place for terminators, others do not. If the wiring adapter is placed right at the SCSI host adapter, you can usually configure the host adapter's on-board terminators to only terminate the high byte. You need to be clear on what type of connectors are present where you want to do the conversion. You also need to plan your bus so that all the WIDE devices will be at one end and all the narrow devices will be at the other end. Certain host adapters with auto-termination make the assumption that when the low byte is terminated the high byte is also. When using WIDE/narrow adapters this assumption is not valid. If for some reason you attach a WIDE device to a narrow bus, you must be sure to disable WIDE negotiation in the host adapter BIOS or the device will hang when it is accessed. One further caveat is that if narrow devices are attached to a WIDE adapter, the adapter's ID must be between 0 and 7 because narrow devices would not be able to see it if the ID was any higher than 7. cheers Jules ===== Backward conditioning: putting saliva in a dog's mouth in an attempt to make a bell ring. ________________________________________________________________________ Want to chat instantly with your online friends? Get the FREE Yahoo! Messenger http://mail.messenger.yahoo.co.uk -- Vintage Macs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> Vintage Macs list info: <http://lowendmac.com/lists/vintagemacs.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/vintage.macs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
