CompuServe Messages

Peter, Thanks for explaning how this works, I am new to this field (as I suspect are many people writing about it). I suppose the safest thing for people to say is "get a SCSI AV drive". I would like to quote portions recent articles, which are a source of confusion: Dr. Ash Pahwa, CD-ROM Professional May 1995, page 104: " To avoid buffer underrun, a fast hard disk should be installed in the system, but this hard disk should not have a "thermal recalibration" feature. (A hard disk with thermal recalibration feature will stop intermittently to dissipate heat from the drive, which can result in a data transfer pause.) Hard disks that do not have thermal recalibration usally have a suffix of AV, which stands for audio video; for example Micropolis makes 2217 and 2217 AV hard didk drives. Jim Seymour PC Magazine mar 14, 1995 page 100: "Look for a 1GB or 2GB SCSI-2 drive, and make sure the one you chose does not use thermal recalibration, a process that stops from time to time to adjust head movements to compensate for changes in temperature. According to a Seagate tech person, these articles should have said delayed or intelligent Tcal, not NO TCAL. Now you are adding that TCAL is only needed under certain conditions. I was looking at your calculations Let me see if I got this right: My system will likely be as follows: 300 KByte per second double speed transfer 1 meg CD-R buffer 6 second thermal recal (a guess) Assuming the the buffer is full, it would empty in 3 seconds, and I would get a coffee coaster. I would be OK if : I had a 2 meg bufferI I had a 3 second TCAL hard disk. Two more questions which occur to me: What happens if the TCAL happens at the very start of writing ?(the buffer cushion is empty) How does your software compensate for this? DON