SCSI Question

[nicowju]

What's the main difference between 50-pin and 68-pin SCSI? Is there a converter or something so that I can use a 68-pin SCSI device on a 50-pin controller?
Thanks in advance

 

[Cyph3r]

Well there are 3 main types of SCSI. SCSI-1, SCSI-2, SCSI-3. There are also sub-categories within those main 3, likw Wide, UltraWide, Narrow, Ultra2Wide and so on..

The 50-pin is usually associated with SCSI-1 devices. SCSI-1 devices are those that toppped out at 10MB/SEC max rate. SCSI-2 improved on that, and if I remember correctly used 50-pin aswell, and gave you 20MB/Sec rates..SCSI-3 is usually 68-pin and rates here go from 40 MB/SEC to 160 MB/Sec..

Drives thare are SCSI-3(regular) are backwardly compatible, so you could most definetly pick up a 68-to-50 pin converter and plug it in. The drive will simply reduce it's capabilities depending on the chain it is attached to.

But, this doesn't work with EVERY drive. LVD(Low Voltage Differential) U2W SCSI-3 drives expect a special LVD cable and may not like being plugged into chains that weren't designed for them..Regards

 

[nicowju]

Alright thanks a lot that was quite helpful

 

[Unbornchicken]

one thing to note. if you have, lets say a 50pin scsi CDROM drive and want to connect a 68pin wide scsi HDD to it, then the scsi HDD wont only downgrade itself from the type of ribbon, but will also downgrade itself to the fastest thing on the chain (the CDROM in this case). So, if you connect an older, SCSI I CDROM that will only do 10MB/s to the chain, then everything else on that chain will do NO MORE than 10MB/s

<correct me if im wrong. this was true with older scsi cards (the 2940UW i know is this way)

 

[Cyph3r]

Unbornchicken, you are correct. On any given SCSI chain, the bandwidth/thruput is set to the LOWEST of them all so that there isn't any problems. This is the reason it's usually good to move slower devices onto their slow chains and faster device onto fast chains, otherwise you've wasted money on faster devices without benefitting from their performance..Regards