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| DATE | Oct 21, 1998 |
| TICKET | #59077 |
| STATUS | Closed |
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Question Details
TICKET ARCHIVE -> CD-R SCSI Throughput
No Wonder User - Oct 21, 1998 - 10:57 pm
Knowledge Level: Expert but stumped
Problem: Software
Computer Type: Apple
Model: PM7600 w/ XLR 220MZ G3 upgrade
RAM: 65+
RAM Enhancer: None
OS Version: MacOS 8
Description:
I have an internal Apple(mitsushi) 8x CD-r. I am using Toast3.5 with a Phillips CD-RW.
When I burn a CD containing data only (i.e. a copy of OS8 ) the throughput of my CD-R is up to 1250k/s. When I insert an Audio only CD something kicks in somewhere that drops the throughput down to 29k/s-130 k/s making it impossible to burn a CD directly from the audio cd.
I can burn a CD by copying the audio files to a hard drive, but the slow throughput is a drawback there also. It takes forever to copy the audio to the HD.
I'm running a very stripped down system (cd driver, audio cd ext, quicktime, not much else).
I've searched for worms, virii, etc.
I can't figure out what is slowing down the SCSI throughput of the CD-r.
Thanks , and good luck.
Send Attachments?
Problem: Software
Computer Type: Apple
Model: PM7600 w/ XLR 220MZ G3 upgrade
RAM: 65+
RAM Enhancer: None
OS Version: MacOS 8
Description:
I have an internal Apple(mitsushi) 8x CD-r. I am using Toast3.5 with a Phillips CD-RW.
When I burn a CD containing data only (i.e. a copy of OS8 ) the throughput of my CD-R is up to 1250k/s. When I insert an Audio only CD something kicks in somewhere that drops the throughput down to 29k/s-130 k/s making it impossible to burn a CD directly from the audio cd.
I can burn a CD by copying the audio files to a hard drive, but the slow throughput is a drawback there also. It takes forever to copy the audio to the HD.
I'm running a very stripped down system (cd driver, audio cd ext, quicktime, not much else).
I've searched for worms, virii, etc.
I can't figure out what is slowing down the SCSI throughput of the CD-r.
Thanks , and good luck.
Send Attachments?
No Wonder Tech - Oct 22, 1998 - 2:25 pm
Troy-
The problem here is that the internal Mac CD-ROM is recognizing the Audio CD. The Audio CD driver tells the Mac that the data *has* to come off of the CD at *audio* rates; it can't be burst-sent, dynamically cached, etc. When you're playing an Audio CD, the CD-ROM goes into a steady-stream mode that sends the audio data at a constant rate so as to allow playback on the Mac with minimal disruptions in throughput. The 1250K throughput is for data, which can be read/written at varying speeds and can be cached more easily, since it can be put into and extracted from cache at varying speeds.
I'm not intimately familiar with Toast; it may in fact be that you'll need to move the data off the CD onto hard drive before burning. I do know that in all the scenarios where I've dealt with burning CDs, it's been imperative to get the data for the CD onto a fast hard drive in a contiguous block so that burning the CD isn't interrupted. I've not actually managed to burn a CD off Toast, although I don't personally own a CD-R(ecordable).
Even with SCSI-1, you should be able to get up near 4MB/sec, better than the 1250K/sec off the CD-ROM.
Thanks for using No wonder! If you have any questions, write me back directly.
J.B. Zimmerman
No Wonder Tech Support
jacobz@nowonder.com
The problem here is that the internal Mac CD-ROM is recognizing the Audio CD. The Audio CD driver tells the Mac that the data *has* to come off of the CD at *audio* rates; it can't be burst-sent, dynamically cached, etc. When you're playing an Audio CD, the CD-ROM goes into a steady-stream mode that sends the audio data at a constant rate so as to allow playback on the Mac with minimal disruptions in throughput. The 1250K throughput is for data, which can be read/written at varying speeds and can be cached more easily, since it can be put into and extracted from cache at varying speeds.
I'm not intimately familiar with Toast; it may in fact be that you'll need to move the data off the CD onto hard drive before burning. I do know that in all the scenarios where I've dealt with burning CDs, it's been imperative to get the data for the CD onto a fast hard drive in a contiguous block so that burning the CD isn't interrupted. I've not actually managed to burn a CD off Toast, although I don't personally own a CD-R(ecordable).
Even with SCSI-1, you should be able to get up near 4MB/sec, better than the 1250K/sec off the CD-ROM.
Thanks for using No wonder! If you have any questions, write me back directly.
J.B. Zimmerman
No Wonder Tech Support
jacobz@nowonder.com
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