Retrospect hangs backing up to DVD, but only with dual 1 GB memory modules in iMac G5

[cpaulu]

This is really wierd, but I added a 1 GB memory module to my iMac G5 (so it has 2x1GB=2GB), and now it can't backup to DVD-R. I exchanged the latter 1 GB module for another, and in all other respects the iMac behaves, so I really doubt it's an issue with the memory per se. It seems to be due to the type of memory addressing introduced by having two large, equal-size DIMMs. But it also works fine backing up to removable disk storage sets. Retrospect only hangs when backing up to the internal Superdrive - and again, only when there are 2 x 1 GB memory modules installed.

 

I tried resetting PRAM, and the open firmware resets.

 

Anybody else seen something like this? Any clues?

[rhwalker]

The thing that makes troubleshooting this difficult is that, unlike the Xserve, the iMac G5 does not have ECC so it's really hard to tell if memory errors are occurring. It would be interesting to know if anyone else has an iMac G5 that has 2 x 1 GB memory modules with your configuration, trying to back up to the internal SuperSrive using DVD-R.

 

Just in case someone has that configuration, could you provide configuration specifics?

 

Retrospect version

RDU version

iMac model

SuperDrive model

Mac OS X version

Whether you did a custom .rdi configuration of your SuperDrive or just used the RDU.

 

Note that the RDU (and custom config) will not be used for removable disk storage backup sets.

 

Russ

[sfgray]

I'm having exactly the same problem, only on an Intel iMac. I had 1G of RAM (two x 512) in the machine when I downloaded the trial version of Retrospect, and it set up and worked flawlessly. Before the trial expired, I upgraded to 2G of RAM (2 x 1G). Now, when I try to do a DVD backup (to media that's already been formatted and used), Retrospect locks up with the SPOD while it tries to read the disc (the "Insert media" dialogue shows "Loading..."). I have a number of DVD backups (all of which worked previously), and the problem repeats on all of them. I've tried running after restarting the Mac, I've tried running the backup scripted and from scratch. Nothing makes any difference.

 

I was running Retrospect version 6.1.126 (again, with a demo serial number, though I assume that shouldn't make any difference). I don't know if it's relevant, but the "About" box also states Configuration 66 K and Device Access Version 1.0.107. The RDU is 6.1.9.102.

 

My machine's an Intel iMac (1.83 Core Duo). The drive is a MATSHITADVD-R UJ-846, revision FB2U. I'm running OS X 10.4.9 (but the problem began while running 10.4.8; I've just checked it under 10.4.9 and nothing's changed).

 

I had to do a custom configuration on the drive, but it worked flawlessly until the memory upgrade. When I tried to reconfigure the drive with a different brand of disc, Retrospect goes through a cycle of locking up for several seconds at a time, then ultimately reports that the media can't be used.

 

I was actually set to purchase a key for the trial version, and would still like to. Do you have any idea what's causing this behavior?

[sfgray]

An update, kind of:

 

I just noticed one difference between the problem under 10.4.8 and 10.4.9. In the former case, I could force quit Retrospect with no (apparent) issues; in the latter case, force quitting Retrospect causes a kernel panic.

[msgreek]

G5 - OS X 10.4.9, 2.5 GB DDR2, DVD+R.

Retrospect 6.1 WILL NOT back-up.

[hermie]

That's it! Thank you guys! I've been looking for the "why" for years now and here it is: apparently Retrospect can't handle 2 GB of installed memory. Something other apps suffered from years ago, but when reported usually got fixed in no time.

 

Same here on my Dual G4 1.42 MDD with 2 GB RAM installed. A long time ago Retrospect worked fine with my internal drive and I've still got the Backup Sets. But then suddenly it stopped. Yes, the tray would open and close, but then it hanged and I had to force quit. Indeed I maxed this machine's RAM out to 2 GB.

 

I tried again an hour ago after upgrading to 10.4.9, hoping - against better knowledge - that this would fix it. To no avail, of course. It's still the same on both my internal NEC and external LaCie D2. The Finder burns, Toast 8.0.1 burns, but Retrospect just slowly dies.

 

Nobody from EMC/Dantz ever answered my questions and at the time I couldn't find it here in the forums either. Until now that is. With on certainty bordering probability Retrospect 6 can't handle muchos RAM. Something that could easily be fixed by the developer and make yours truly a lot less angry. Why angry? Cuz it looks like EMC just doesn't care about Macs anymore. OK, just my opinion of course and I hope to be proved wrong...

 

Thanks and have fun, Hermie

[rhwalker]

Sfgray and Hermie:

 

Quote:

---

I just noticed one difference between the problem under 10.4.8 and 10.4.9. In the former case, I could force quit Retrospect with no (apparent) issues; in the latter case, force quitting Retrospect causes a kernel panic.

 

---

If you are force quitting Retrospect, then you will get corrupt preference files for Retrospect that will prevent correct operation (if you haven't already caused this problem). So your issues may be different. You may need to trash the preferences and retrorun file and reconfigure.

 

Hermie:

 

Quote:

---

Nobody from EMC/Dantz ever answered my questions and at the time I couldn't find it here in the forums either. Until now that is. With on certainty bordering probability Retrospect 6 can't handle muchos RAM.

 

---

Realize that there are several issues at play here.

 

First, Retrospect has no problem at all with >= 2 GB RAM in a PPC machine if the RAM is good. I've got an existence proof for that with our Xserve G5, as do many others.

 

Second, whether on an Intel Mac or on a PPC, Retrospect uses lots of memory and exercises it very hard. If your memory is not good, or if there are motherboard issues that cause memory issues, then hangs and errors, etc., with Retrospect will happen. If you do not have ECC memory (Xserves and some of Apple's tower models support ECC) then there's no way to tell if you are getting occasional (or frequent) memory errors. If removing some memory causes Retrospect to work, my first suspicion would be that the memory is bad. I would suggest more thorough regression testing, such as removing the existing memory and replacing it with the suspect memory, see what happens, or replace the suspect memory with memory from a good souce (Apple or Crucial).

 

Third, only on the Intel Mac, Retrospect is running emulated under Rosetta because it is not a universal binary application. Rosetta has its own issues about memory limits, and there is the possibility that there are memory issues when running Retrospect under Rosetta.

 

The original poster's problem is not a Rosetta issue because the hardware configuration was described as an iMac G5, but there may still be bad or marginal memory involved. The original poster did not provide memory brand information, or whether the memory was added by Apple using Apple memory. So, the cause of the original poster's problem is not known, but I still suspect bad memory.

 

Quote:

---

it looks like EMC just doesn't care about Macs anymore. OK, just my opinion of course and I hope to be proved wrong...

 

---

This may or may not be true, but it doesn't address your issues, which seem to point to a hardware problem.

 

Russ

[hermie]

Hi Russ,

 

Thank you very much for chiming in!

 

OK, so when Retrospect has no problems with over 2 GB of memory G4s, what else can be the problem? It works just fine backing up to my second internal HD and to my external LaCie pocket drive, but hangs after a few seconds with both my DVD drives. So weird, I just don't get it and have tried just about everything i could think of.

 

The installed memory from 2003 has never given me any problems whatsoever. It always shows up after a system update and all memory testing apps I've tried gave it a clean bill of health. No problems with other apps either.

 

Anyway, this is what I've got on the memory: 3 extra ones put in 512MB Samsung/Apple M8833G/A M368L6423DTLCB3 PowerMac G4 PC2700 DDR (p/n M8833G/A). I really don't feel like opening the machine and pulling them just in case Retrospect could be extra picky when I never have any other RAM-related problems. Sorry!

 

In the light of EMC letting the Mac version die off I've been looking at BRU LE. It doesn't seem to support DVD backups though, so that can't replace Retrospect either. Oh well...

 

Thanks again and have fun, Hermie

[rhwalker]

Quote:

---

OK, so when Retrospect has no problems with over 2 GB of memory G4s, what else can be the problem? It works just fine backing up to my second internal HD and to my external LaCie pocket drive, but hangs after a few seconds with both my DVD drives. So weird, I just don't get it and have tried just about everything i could think of.

 

---

Well, that's a different (more complete) statement of the problem than you originally provided. I can't speak to whether there is some odd issue involving backups to DVD or whether that is related to memory issues. We have only backed up to tape in our autoloader on our Xserve G5, and have never done a backup to DVD.

 

Your discussion about the memory, and the fact that it has been working since 2003, probably means that the probability of a memory problem in your case is extremely low. However, many people have noted problems with DVD backup and Retrospect. You haven't provided any configuration information about your DVD drive(s), so it's not possible to tell whether you have supported drives. But that different statement of the problem seems to indicate that yours is an issue with the DVD drives (whether they are unsupported, or whether there is a different hardware issue at play, or whether there is a Retrospect bug interacting with your configuration, is unknown).

 

Yours seems to be a different problem than the original poster's. You might want to start a separate thread rather than hijacking this one.

 

Russ

[sfgray]

I'm not sure which one of us you were referring to, but from what I see, nobody's hijacking anything here. All three people who have posted here have exactly the same problem: With less than 2G of RAM in a machine, Retrospect works fine while backing up to DVD media. With 2G of RAM in the same machine, with the same DVD drive and no other changes to system configuration, Retrospect hangs when backing up to DVD media.

 

(As an aside, all three of us have stated pretty clearly that we've used our systems for successful backup before the memory upgrade. This would seem to preclude the question of whether our drives are supported.)

[hermie]

I'm sorry Russ, but hijacking? I started another thread more than a year ago and never got an answer. Then i saw more people experiencing exactly the same issue as I do and they all increased their memory. So to me it looks like Retrospect can handle this alright when backing up to another HD, but gives up the ghost when it has to deal with DVD drives.

 

Yes, it sees the drives, both of them. It opens and closes the trays and tells me the disc (Verbatim) is erased. But reading an old backup set or writing to a new one, forget it! It doesn't do a thing and hangs after a while. Hmmm, hangs might not be the correct term because when I push the button on my external FireWire drive to eject the disc Retrospect comes to life again asking me if I want to try another disc... So, something is seriously wrong with Retrospect communicating with disc drives combined with a lot of RAM.

 

Anyway, my internal is a _NEC DVD_RW ND-3520AW (supported) and the external FW drive is a LaCie TSSTcorp CD/DVDW SH-S162L (skipped for support it seems).

 

As more people here noted: it worked fine before! And other disc burning apps like Toast 8 still do. But not Retrospect, and you can't ask people to remove memory every time they want to run a backup. So unless EMC/Dantz does something about it, we've had it. OK, we've had it. I suppose I'd better start looking for a consumer-type tape drive and go for BRU or something like that, because I still want a backup on "hard" media, given the nature of HDs crashing.

 

Oh well, thank you all for reading this far and have fun!

 

Hermie

[Skipjack]

Well, has anyone resolved this issue yet? I have been using Retrospect just about since its creation and have had no real issues till guess what? I installed additional memory. 2gigs to be precise. And since doing so, guess what? Retro can not access my DVD's anymore. Just sits there and says "loading" sounds familiar according to this thread. But I see no resolution yet. Anyone?

 

 

Info: Running the latest Retro 6.1. G4 dual mirror door MAC, 2gigs ram. And a Lacie (always has worked before) DVD burner. Anyone?

[Skipjack]

Well, just an update to the post above. I removed two (2) gigs of recently installed memory this morning and guess what? Retrospect ran just fine. Go figure. I would think Retrospect has an issue which needs to be addressed. If only!!!!!!!!!! I will put the memory back in tonight and see if the issue repeats itself, which will be proof of a software issue. I'll be back.

[Mayoff]

Sounds like you have some bad RAM. Time to swap it for different memory.

[Skipjack]

Purhaps, but it's all the same ram. It works on two of them and not four. I will try to swap them around and see what happens. I'll try three as well and see what happens.

 

And of course it's always an easy out to blame it on something other than software. I should be seeing other issues across the board if it was a bad memory issue, correct?

[rhwalker]

Quote:

---

And of course it's always an easy out to blame it on something other than software. I should be seeing other issues across the board if it was a bad memory issue, correct?

 

---

You may be having other issues and not know it. Only way really to know is if you have ECC memory. I've got an existence proof in the next room that Retrospect runs fine with > 2 GB RAM on an Xserve G5.

 

Everything in your posts points to bad memory. Sorry you can't accept that.

 

Retrospect is doing continuous DMA with large transfers. Lots of I/O through the DMA channel. That's not the normal pattern of operation (unless you have a server). In user machines, DMA generally occurs in the system's buffers. Here, it is happening from the user memory.

 

Russ

[Skipjack]

Have ya read the other posts? It's not a matter of Retro working with 2gigs. It's a matter of Retro NOT working with a DVD and 2gigs. I have retro running all my normal backups onto hard drives NO PROBLEM with the full ram loaded. It's just the DVD drive issue. And yes my drive is compatable. Been using it for the last year or so. As posted in others all other associated software that accesses my DVD works just fine. So I beg to differ with you. It is without question a Retro RAM/DVD associated issue. So I'll leave it at that and move on.

[rhwalker]

I just tried moments ago with our Xserve G5, and was able to back up to a DVD with > 2 GB RAM.

[jcr]

Not to sound harsh, Russ, but you really need to do a careful reading of previous posts. The problem reportedly happens with = 2 GB RAM, not > 2GB RAM.

 

I am a longtime (since version 2) Retrospect user, and an even longer experienced Mac user, and the problem I am experiencing is fairly clearly a software bug. While it is technically true that you can't be sure you don't have memory errors in non-ECC memory, that isn't really helpful as the vast majority of Macs don't support ECC. I agree with you that bad RAM is subtle, insidious, and difficult to diagnose, but bad RAM does not affect a only a single aspect of a single application like we are seeing here. There are plenty of other RAM-intensive applications, or for that matter OS X itself, that would likely show instability in the presence of bad RAM.

 

If it was bad RAM being triggered by DMA transfers, we would see it during writes to disc, not when simply loading a DVD in the devices window. Also, we would see it during backup to hard disk as well, which we don't.

 

I'm not sure of the all the specifics of the bug, but with the unduly heavy processor use during a permanent (or at least several hour) hang, my guess would be that infinite loop is somehow being triggered in the routine that reads the DVD drive when 2gigs of RAM are present.

 

I submitted the following bug report to a very helpful individual at EMC customer service, who very kindly promised to forward it on to the Retrospect engineers today.

 

John

 

- - ----------Begin Bug Report------------

 

Subject: Bug Report: Retrospect 6.1 Mac hangs on accessing DVD drive when 2gig RAM installed

Date: 4 May 2007 12:00:26 pm GMT-04:00

 

EMC SOFTWARE PRODUCT AND VERSION WITH SPECIFIC PATCH OR RELEASE LEVEL:

 

Retrospect Desktop for Macintosh 6.1.126

 

Retrospect Driver Update 6.1.10.100

(also occurs with RDU 6.1.9.102, and with no RDU present)

 

 

PLATFORM OPERATING SYSTEM WITH VERSION NUMBER:

 

Computer:

Machine Name: PowerBook G4 17"

Machine Model: PowerBook5,7

CPU Type: PowerPC G4 (1.2)

Number Of CPUs: 1

CPU Speed: 1.67 GHz

L2 Cache (per CPU): 512 KB

Memory: 2 GB

Bus Speed: 167 MHz

Boot ROM Version: 4.9.1f1

 

DVD Drive:

Model: MATSHITADVD-RAM UJ-85JS

Revision: F8X8

Serial Number:

Detachable Drive: No

Protocol: ATAPI

Unit Number: 0

Socket Type: Internal

 

 

PROBLEM DEFINITION INCLUDING ANY ERROR MESSAGE(S):

 

Retrospect hangs (freezes) with rainbow-cursor Spinning Pizza of Death (SPOD) when first attempting to read DVD (-R +R +RW +R DL) or CD-R disc drive. The disc sounds like it spins up, then the hang occurs. several seconds later, the disc spins down. Activity Monitor indicates Retrospect is not responding, and is taking an inordinate amount of CPU (as high as 90%). This hang seems permanent, or at least lasts several hours overnight. Retrospect requires a force quit (kill). No error message appears. Nothing is reported in the Retrospect log or the Console.

 

This hang occurs any time Retrospect attempts to read or access a disc in the drive. It is independent of any initial preparing, reading of catalogs, local drives, or network clients (which Retrospect completes successfully). Backup to an external hard disc completes successfully, it is when accessing DVD drive only.

 

Hang only occurs just as Retrospect attempts to access a disc in the DVD drive, For example, Retrospect will show the empty drive in the Storage Devices window, listed as "No Media", but upon insertion of any disc media (blank or not) cursor changes to moving gears and window reads "Loading...", you can hear disc spinning up and read-head motion, then cursor changes to SPOD and Retrospect hangs.

 

Hang also occurs during a backup if a member of a backup set is inserted previously, just after the matching stage is completed, as Retrospect first begins to access drive in preparation for writing.

 

Attempts at a custom configuration of drive also triggers problem at the same stage in the process.

 

Now the interesting bit: The problem only occurs when 2 gigabytes of memory are installed in the Powerbook. Removing/replacing EITHER 1-gig SO-DIMM to change memory configuration to <2 gig installed cures this problem! Retrospect is able to custom configure the drive and backup and verify sucessfully to DVD media just fine running on 1 gig of installed RAM! I added in a 512-meg module and successfully completed a test backup to DVD under 1.5 gigs of installed memory. But if I replace the removed 1-gig DIMM to bring the total installed back to 2 gigs, the problem reoccurs. I am not able to test configurations above 2 gigs, since that is the max on this model of Mac.

 

I don't suspect a bad DIMM, because Retrospect will run as normal under either one, just not both. Also, I am experiencing no to other application or system instability. In addition, Retrospect successfully backs up my local drive and two remote clients to a hard disk under 2 Gigs; I would expect any bad RAM issues to occur during the memory-intensive catalog-matching process. Instead the hang only occurs during the DVD access, even when just accessed via the configure devices interface.

 

 

OTHER TROUBLESHOOTING ATTEMPTED BEFORE ISOLATING THE 2-GIG FACTOR:

 

Downloaded and reinstalled fresh copy of Retrospect 6.1 from EMC/Dantz site (unsuccessful in curing problem).

 

Installed fresh copy of Retrospect Driver Update 6.1.10.100 (unsuccessful)

 

Reverted to fresh copy of RDU 6.1.9.102 (unsuccessful)

 

Tested with no RDU present (unsuccessful)

 

Fresh media in various formats. (unsuccessful)

 

Existing know good backup set member media in various formats (unsuccessful)

 

Delete custom configuration (unsuccessful, and new custom config attempts triggered bug!)

 

Backup to file on external Hard Disk (successfully on 2 gig configuration)

 

Deleted preferences by removing all files in /Library/Preferences/Retrospect/ and ~/Library/Preferences/Retrospect/. (Also note that some of the successful DVD backups under the 1-gig- and 1.5-gig- configurations were with old preference files restored.)

 

CONCLUSION AND NOTES:

 

This problem has also been noted by others in the Retrospect forums, specifically at:

 

http://forums.dantz.com/ubbthreads/showflat.php/Cat/0/Number/94582

 

This is why I initially tried removing 1gig of RAM to test. I suspect that many others are experiencing this problem but are unaware of the 2-gig variable. This should probably be propagated to your support staff as well.

 

Thanks for your attention to this report, and please let me know if I can provide any additional information. I would be happy to provide logs, perform additional testing, test beta versions, etc. I am eager to help fix this bug, so I don't have to uninstall a DIMM from my system every time I want to back up with Retrospect. ;^) Feel free to contact me by email at [redacted]; you can also reach me at [redacted].

 

- - ----------End Bug Report------------

[rhwalker]

Quote:

---

Not to sound harsh, Russ, but you really need to do a careful reading of previous posts. The problem reportedly happens with = 2 GB RAM, not > 2GB RAM.

 

---

Sorry to have tried to be helpful.

 

FYI, moments ago I tried with exactly 2 GB RAM, and the results were as before. Perhaps it's something specific to your powerbook G4 or the original poster's iMac or G4 processors in general. But it's not as broad as exactly 2 GB RAM or more than 2 GB RAM. It doesn't happen on an Xserve G5 single processor with exactly 2 GB ECC RAM or more than 2 GB ECC RAM running Mac OS 10.4.8 server, stock Matsushita Superdrive UJ-845, Retrospect 6.1.126, RDU 6.1.10.100. At least not on ours.

 

Admittedly, I only did a simple test case to try what the original poster reported. We do not do DVD backups, only tape to our Exabyte VXA-2 1x10 1u PacketLoader (SCSI, attached to an ATTO UL4D), so, if it is a rare race condition (hard to see how it could be), then my quick testing wouldn't have caught it.

 

As for submission of bug reports, I've submitted my share over the years under our service contract and have NEVER seen any of them fixed. NEVER. The product isn't perfect, and far from it, but I did try the steps the original poster suggested on as close of a configuration as I could, just to try to be helpful.

 

I have used Retrospect, I would guess, as long as you have (since version 2.0). I have a bachelor's degree in EECS from MIT and a master's degree in EECS from MIT. I spent about a dozen years designing computers and OS internals and drivers before I changed careers, and I have done a couple of unix ports. While it is possible that this is caused by a software bug, it appeared (and still does appear) to me to be more likely a hardware issue. I have not seen the testing done in these posts that would eliminate the possibility that it is a hardware bug.

 

Perhaps I'll just stop responding to requests for help. That will make it simpler. Good luck.

 

Russ

[jcr]

No offense intended, Russ.

 

You seem pretty convinced that it is bad RAM. If so, it only manifests when Retrospect accesses a DVD drive.

 

I think I have shown that the hang does not occur with either RAM DIMM alone, but does with both of them bringing the config to 2GIG. Likewise, the bug does not occur when backing up to hard disk with 2gig installed. For me, that would eliminate RAM errors as a sole cause for all practical purposes.

 

The DVD drive itself behaves fine with all other DVD-writing applications. Even if the DVD drive itself were malfunctioning, I wouldn't expect Retrospect to hang, I would expect it to time out or report an error.

 

So the only constant in the problem scenario is Retrospect. Given the complexity of dealing with the wide variety of writable hardware Retrospect does, combined with the lack of updates to the program even as bug fixes, my instinct is that it is more likely a rarely-triggered software bug.

[rhwalker]

If the DVD is used as a raw device (only Retrospect has access to it), the I/O would come from user space. Disk I/O, because disks are mounted devices, come from buffers in the kernel. The buffers are in different DIMMs in memory.

 

One difference I note with your tests is that you were able to reproduce the problem with custom configuration; I have never configured our DVD drive with Retrospect, so there was no .rdi file and never has been one. Unrelated to this issue, our DVD drive is marked to be ignored in Retrospect while we back up to tape (and we only back up to tape) as a workaround for another bug that I reported back in 2005 (which has never been addressed). I had to "unignore" the DVD drive in order to attempt to reproduce this issue (in addition to changing memory configurations).

 

But I'm not going to argue with you; I just didn't see it in my simple test on our configuration. I'm not trying to be difficult, but just to emphasize that I wasn't able to reproduce the problem as stated. Either it's a software bug sensitive to configuration differences (or to the fact that we run Mac OS Server), or all the variables necessary for the software problem to occur have not been stated, or else it's a hardware problem caused by bad RAM. I do appreciate the time you took to turn in such a good bug report. Few people are able to do so.

 

Russ

[Skipjack]

Quote:

---

Not to sound harsh, Russ, but you really need to do a careful reading of previous posts. The problem reportedly happens with = 2 GB RAM, not > 2GB RAM.

 

I am a longtime (since version 2) Retrospect user, and an even longer experienced Mac user, and the problem I am experiencing is fairly clearly a software bug. While it is technically true that you can't be sure you don't have memory errors in non-ECC memory, that isn't really helpful as the vast majority of Macs don't support ECC. I agree with you that bad RAM is subtle, insidious, and difficult to diagnose, but bad RAM does not affect a only a single aspect of a single application like we are seeing here. There are plenty of other RAM-intensive applications, or for that matter OS X itself, that would likely show instability in the presence of bad RAM.

 

If it was bad RAM being triggered by DMA transfers, we would see it during writes to disc, not when simply loading a DVD in the devices window. Also, we would see it during backup to hard disk as well, which we don't.

 

I'm not sure of the all the specifics of the bug, but with the unduly heavy processor use during a permanent (or at least several hour) hang, my guess would be that infinite loop is somehow being triggered in the routine that reads the DVD drive when 2gigs of RAM are present.

 

I submitted the following bug report to a very helpful individual at EMC customer service, who very kindly promised to forward it on to the Retrospect engineers today.

 

---

 

EDIT: Maybe you can let us know how we can forward the same report to EMC. Purhaps getting several reports with the same issue will bring it extra attention.

 

Thank you John for that great "bug" report. Your problem, as described, is identical to mine in every aspect (reported in another thread). And I for one appreciate your valuable imput to EMC. I just hope that something will come of it. Because it's no fun and unsafe taking out 2gigs of ram every other day just to get my stuff backed up. So, once again, thanks. Jeff

[AndrewA]

I just tried this setup on my Mac G5 that came with a Sony DW-U21A DVD drive, first tried it with 1GB worked fine and then tried it with 2GB and was able to append and backup to a new backup set just fine. Although this was with 4 512MB sticks I was not able to reproduce this problem either.

[rhwalker]

Just as a data point, when I tried it in our Xserve G5, the ECC DRAM modules were all 512 MB each (and I had success with 2 GB and with > 2 GB). Hard to see how this could affect things, but I provide it as a data point. As I indicated, I think that this problem, if it is not due to bad RAM as I still suspect is the case, is related to some specific configuration differences between the posters that are having problems and those that are not.

 

Russ