larth Posted May 16, 2002 Report Share Posted May 16, 2002 Anyone know why Retrospect is only writing to DVD-R at about 25 percent of the drive's top speed? I've got a Pioneer DVR-104 (a.k.a. SuperDrive), and using Toast I can get close to 160 MB/min. But doing a Retrospect Backup of the exact same files achieves only about 40 MB/min. of sustained write speed. That's quite a trade off to keep Retrospect's nice feature set. Do I really have to live with this weak performance? --larth Link to comment Share on other sites More sharing options...
AmyJ Posted May 17, 2002 Report Share Posted May 17, 2002 The DVR-104 drive does not support continuous writing. From the Knowledgebase: http://www.dantz.com/index.php3?SCREEN=knowledgebase_article&id=870 ----- Retrospect uses packet writing technology to write to CD and DVD drives. Packet writing speed is determined entirely by the device in use. That is, Retrospect does not determine what speed the device can support, it simply sends data to the device as fast as it can write it. Some CD/DVD drives do not support "continuous writes" in packet writing mode. In these cases, Retrospect must tell the device to write each packet, and then give it a new packet only when it has finished. Because this is inherently less efficient than buffering data and writing many packets in a row, devices that require a flush after each packet, as this functionality is called, will be much slower than their normal "disc at once" burn speed. For example, you may have a 24x drive that only writes at 4x speed with Retrospect because the drive does not support continuous writes. This doesn't mean the drive doesn't work, it just means the drive works slowly with Retrospect. Obviously the best CD/DVD drives to use with Retrospect are ones that support continuous writes. Link to comment Share on other sites More sharing options...
larth Posted May 17, 2002 Author Report Share Posted May 17, 2002 > The DVR-104 drive does not support continuous writing. Boy, that would've been valuable information for Dantz to include in the Backup Hardware Compatibility database. I notice, too, that other drives in the database _do_ have a warning about this, but not the DVR-104. Hey Dantz, get that info in there! > "Obviously the best CD/DVD drives to use with Retrospect > are ones that support continuous writes." Any recommendations? Are there any DVD recordable drives that do support continuous writes? --larth Link to comment Share on other sites More sharing options...
Peabody Posted May 25, 2002 Report Share Posted May 25, 2002 Yes, that would have been nice to know. I talked to Apple & Dantz when inquiring about replacing my Travan tape backup with the new iMac's internal Superdrive for backup purposes. No one said word one about it not being a continuous write drive. 2x speed on a DVD/RW running Retrospect is agonizingly slow. I may have to go back to my tape drive on an older Mac....this after spending $1,800 on a new computer and another $130 to upgrade Retrospect and a client. Way to go Apple and Dantz Link to comment Share on other sites More sharing options...
AmyJ Posted May 28, 2002 Report Share Posted May 28, 2002 The information for the DVR-104 has been updated in the Hardware Search Engine. Currently, the only DVD-R devices qualified for use with Retrospect on the Macintosh are the DVR-104 and DVR-103. Neither of these drives support continuous write. The majority of DVD-RAM drives are qualified. For detailed information, please see the Dantz Hardware Search Engine: www.dantz.com/hardware New device support is continually being added. Link to comment Share on other sites More sharing options...
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