In a message dated 10/17/01 9:11:44 AM, [EMAIL PROTECTED] writes:
<< Please elaborate on the ultra wide scsi. What kind of a card does this (on a 520) and how much does it cost? How much faster speed does ultra wide give you, or is it a matter of being able to use more current devices? >> The 520/540/550's external SCSI port is limited to 5 MB/sec. This is often referred to as Narrow SCSI. There is a variant of this 8-bits-wide SCSI called Fast SCSI. This is used internally in the 7500 and other similar Macs. This is 10 MB/sec. But, on machines so equipped, the external SCSI port is still 5 MB/sec. And, this external port is on a separate SCSI bus controller chip on many Macs. An UW-SCSI port is 16-bits-wide, and is, consequently, capable of faster aggregate transfers. Certainly 20 to 40 MB/sec, unless it is forced into 8-bits-wide mode by the device. There is a 160 MB/sec variation. I believe the PCMCIA UW-SCSI cards are from Adaptec, but there could be others. Most servers use UW-SCSI. Current LVD (low voltage differential) SCSI drives are generally compatible with single-ended SCSI, such as Narrow, Fast, and UW-SCSI. -- PowerBooks 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> PowerBooks list info: <http://lowendmac.com/lists/powerbooks.shtml> 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/powerbooks%40mail.maclaunch.com/> Using a Macintosh? Get free email and more at Applelinks! <http://www.applelinks.com>
