Reading R'spect DVD-R's in standard DVD drives

[cgm]

Hi,

 

 

 

So I whip up a Restrospect DVDR backup set on my whizzy firewire Pioneer DVD-RW DVR-103 (driver Pioneer DVD/CD-RW 1.51) sold by LaCie. It backs up fine.

 

 

 

BUT when I'm on the road with my laptop and go to restore a file, I put the DVD-R into my TiBook DVD and what does Retrospect see? Nothing!

 

 

 

Help! I have a write-only backup!

[IrenaS]

If both drives are qualified DVD-R drives, Retrospect should be able to read them. Note that they will never mount on the desktop, but they shoudl report the correct name from Retrospect's Configure > Devices window.

 

 

 

What is the mechanism of the drive in the TiBook?

 

 

 

Irena Solomon

 

Dantz Tech Support

[cgm]

Thanks, Irena!

 

 

 

The internal DVD-ROM drive on the TiBook is a Matshita DVD-ROM SR-8187.

 

What I was hoping to do was create a backup set on my (external, stationary) firewire Pioneer 103 DVDRW drive with a DVDR disk. (I figured asking the DVD-ROM drive to read RW might be a bit of a stretch.)

 

 

 

Then, when on the road, I want to be able to use that disk to restore any files that get broken from the Tibook DVD-ROM drive (built-in) that can run off battery and is thus mobile, which the DVDR is not.

 

 

 

Retrospect doesn't appear to see the DVD-ROM drive at all, certainly not as a legitimate device for restore or DVD source for a (read-only) restore session.

 

 

 

 

 

 

 

 

[IrenaS]

A DVD-ROM drive isn't going to be able to read a Retrospect-created DVD-R, just as a CD-ROM drive can't read a Retrospect CD-R. Retrospect doesn't finalize the disc, so it will never mount on the desktop and will only be accessible through Retrospect when inserted in a supported burner.

 

 

 

You'll need to use a DVD-R drive to restore data from your DVD-R discs.

 

 

 

Hope this clears up the confusion!

 

 

 

Irena Solomon

 

Dantz Tech Support

[davidduff]

i feel this is a serious shortcoming of the current design of retrospect, both for dvd-r and cd-r drives. i suspect that many people (myself included) were not fully aware of this when they bought retrospect and/or started using cd-r or dvd-r as a backup medium.

 

 

 

one of the strengths of cd-r (and probably soon, dvd-r as well) is that almost every machine is equipped with capability of reading the discs.

 

 

 

the main reason that most people do backups is to protect themselves against various types of equipment failures or other human errors.

 

 

 

clearly, it's possible in general to write cd's that can be read in any normal cd-r drive (and likewise dvd's). yet dantz chooses to write data in a format that can only be read in packet-writing drives. this seems like a poor design trade-off in my opinion.

 

 

 

i would much rather see a version of retrospect that...

 

 

 

- writes (and reads) cd-r's at the full rated speeds of the drive (e.g., "24X", etc) instead of a much slower speed as does the current version of retrospect.

 

 

 

- works with essentially all common cd-r drives instead of a small certified handful of drives like the current version.

 

 

 

- writes data in a format such that it can be read back on the widest possible set of drives. i.e., for cd-r, it can be read on any cd-rom drive and not just on packet-writing cd-r drives as is the case with the current version.

 

 

[IrenaS]

Thanks for the feedback. Retrospect does not write using track-at-once or disc-at-once to maintain data integrity. We also do not finalize the CD so that you can append data to a CD-R over multiple sessions.

 

 

 

I will certainly log your comments as suggestions to our developers though.

[davidduff]

irena, thanks for the response.

 

 

 

a few brief responses to your comments:

 

 

 

data integrity can be maintained in other ways (for example using checksums and/or cylic redunandancy checks, either embedded in the data stream or out-of-band as a separate signature). packet writing is certainly not the only way to achieve data integrity.

 

 

 

there are other ways that you can write cd's to allow data to be appended. multi-session writes are already a commonly supported format for doing this. so again, packet writing is certainly not the only way to achieve the ability to append data. (anyone who's used roxio toast can attest to this).

 

 

 

thanks again,

 

dave

 

 

 

 

[alan7410]

Finally a thread on this!

 

I am now running into a big problem where this plays out... I have 26 DVD-R's I need to retrieve to an older iMac DV SE using a Matshita DVD-ROM SR 8184. These were burned on my 04 PB G4 Superdrive. Now my PB is out of commission for a week or so because of a bad HD and I need the data bad for a major project. Retrospect should rethink this and make an update or stand alone program that could read these disks for customers like us who don't want to shell out hundreds of dollars for another piece of hardware that may only be used for a couple days.

 

just my two.5 cents

 

 

Scott

[dhwagner]

On the other hand, I just (a month ago) put together an external firewire burner with a Pioneer DVR-109 and a nice aluminum case for about $93 shipped, from Newegg.com. Check out dealmac.com. These things have become incredibly cheap.

 

BTW I just noticed that the DVR-109 is now qualified for use with Retrospect! Hurray!

[Tramper]

I have long suspected that the (many) problems Dantz has with compatibility, etc., come from choosing to use a very low-level approach to interacting with the drives. This makes the software very dependent on the exact drives and driver software. I'd like to think there are "higher level" and less device-dependent approaches to solve the problems that Dantz claim to need these low-level approaches and some of the posts here seem to indicate that there are. I would strongly urge Dantz revisit how their software interacts with drives (more accurately, drivers) and at least try provide "higher-level" options so that users can opt out of the current low-level approaches, even if there is some lose of fine granularity, as their is likely to be.

 

Higher-level solutions might not be so much fun to the engineers, but... client's first? I also wonder if this approach stems from the heyday of the tape drive...?

 

I haven't seen anything to indicate that other backup software for the Mac has these problems; I have this nagging suspicion that the reason is that they use fairly high-level approaches to interacting with the drives, letting the low-level software present worry about the finer details.

 

I'm having to move off Dantz for reasons related those discussed in this thread: writing to DVDs doesn't seem to work (for Mac G5s at any rate) for reasons that sound very much like the elements here. I've waited more than long enough, so I just have to move on (practicalities and all that).

[natew]

Hi

 

Retrospect's approach to writing optical media is unique and really quite good. Lets face it, optical media is cheap and easy to use - not terribly reliable however. The same can be said of OEM DVD/CD burners. (Yes, even the ones directly from Apple)

 

Becuase of Retrospect's write methods if a backup is sucessful you can count on the discs to be good. If the backup fails it will fail during backup _before_ you need to do a restore.

 

Annoying? yes. But it is still the best approach.

 

The big thing that Retrospect does that other software doesn't is allow true multisession access until the media is full. It also allows for a streaming write of data that adjusts to the speed of the source volume. It seems simple but it is just a lot more complex than it seems.

 

Thanks

nate

[thraxisp]

I reported the same thing in another thread. It seems that the backups are great. I've never had any trouble recovering from a file I deleted.

 

Over the years, I have had a great deal of difficulty recovering disks on machines other than the ones they were written on. Denser disks (DVDs) seem to be impossible to move.

[rhwalker]

My complements and thanks to the Dantz programmers for the Macintosh RDU version 6.1.2.102 (Retrospect 6.1). I had given up on Retrospect DVD backup for long-term storage, and had just accepted that Retrospect only seemed to work well with tapes. But using the RDU issued yesterday I am now able to back up to DVD using the UJ-845 drive on our Xserve G5. Didn't work with Retrospect 6.0, but seems to work now. I had tried both Apple DVD-R media and Memorex, no luck, but trying a DVD-R out of the same Memorex stack now works. DVD and even DVD DL is not big enough for daily backup, but it's nice for long-term storage of important files. Thanks.

Russ

[wkegel]

If you read this and similar threads carefully, you can only conclude that you should think twice before deciding to use Retrospect for archiving files on DVD. You cannot be sure that by the time you need that data you still have access to the machine used to write the data, and you have no guarantee that the disc will be readable on a replacement machine. The iMac I use to write this is 16 months old; I still cannot read backups I wrote on it's predecessor and I have given up hope that Retrospect will ever support my current configuration.

 

Burning an hybrid disc with Toast may be less convenient, but gives you a much better chance to actually retrieve that essential file you are looking for in two years time - especially if you make two copies. Use Disktracker to keep a catalog of what's on those disc and you have a combination that offers almost equivalent functionality and in practice much greater reliability.