In response to our recent WFTD, Asynchronous (inSync 5/6/98), and other related issues we’ve covered on inSync recently, Tom K writes to give us a little more information about what the issues really mean to us.
“I noted your description on SCSI transfer modes today. Interestingly, the synchronous vs. asynchronous behavior only applies to the actual “data” portion of a SCSI transaction between a computer and some sort of peripheral device. The remaining phases of a transaction are all effectively governed by the asynchronous interlocked, transfer rules.
While this might be a minor point in most instances, it does become significant as SCSI devices support faster synchronous transfer parameters. As the elapsed time for the data phase decreases, it no longer dominates the overall time for a SCSI operation to complete. It’s similar to driving to the mall to go shopping. If you spent an hour driving, and four hours shopping, the drive won’t seem like much. If you’re only in the mall for 10 minutes, though, the drive might seem quite long. This also helps to explain why simply doubling the speed of SCSI doesn’t always translate into twice as many digital audio tracks in a session (or whatever one is using the data for). It takes a certain amount of “drive time” just to get the SCSI bus (and the disk drive, for example) to a point where you can actually pick up the data, and return home. The less time one spends picking up the data, the more that the “drive time” becomes apparent.”
Thanks Tom, and others who have written. It’s great that we have so many knowledgeable and helpful people to enrich the quality of inSync for everyone.