Communication Failure / DMA



Dear all,

Last week I got a new Sony DVD drive which came with Nero software. Using Nero Backitup to back up MS Word files from my hard drive, I could successfully burn a single file or a small folder say about ten files, but whenever I tried to burn something bigger, I would get
Communication Failure
Burn Process Failed at 4 x (5,540 KB/S)
Back up Process Failed.

Looking at the Nero website I have isolated the cause of this problem: In Device Manager, when the Secondary IDE Channel Transfer Mode is set to ‘DMA if avaliable’, the burning process is always (except for very small projects) interrupted by ‘Communication Failure’. When the Transfer Mode is set to ‘PIO only’, the burning process works ok.

Can anyone explain what DMA / PIO mean and why this happens.



(CPU AMD Athlon XP2400+ (2Ghz); RAM 512MB; HD Maxtor 80MB)


I had this exact same problem; neither Backitup or InCD would complete burn except for very small number of files. I wish I had looked at this board & your post early on as I would have saved over a day of fiddling. When I changed Device Manager setting for secondary IDE to your fix, everything started working correctly. It’s strange because FAQ recommends DMA setting but also said if that doesn’t work try PIO.

I don’t know if you & I are the only 2 to experience this problem, but I would think it warrants greater coverage/clarification in FAQ as well as keyword indexing.

Regards, Ron


@ Charles1, cove3
A ‘Communication error’ many times is the result of a bad or loose IDE cable or a 40-wire IDE cable in use where an 80-wire cable should be. Your system probably defaults to “current transfer mode= PIO only” mode to compensate for the lack of available bandwidth(data transfer rate), so it works there for small data transfers but not large data transfers. BUT, your ‘current transfer mode’ should be at ‘ultra dma mode 2’ or something similar(but not ‘multi-word dma mode 2’, that is also a lower level of bandwidth). The nero instructions leaves out that you must restart after selecting “dma if available” in the 'transfer mode" window. I would be surprised if you could burn any dvd with your DMA(Direct Memory Access) set to ‘PIO’(Programmed In/Out) mode.

You can check here for more info. At the bottom of that linked page there are instructions of how to enable if merely selecting and restarting don’t work. You can also run ‘nero cd-dvd speed’ test to check your burst-rate(or what your transfer rate is). Go ‘nero>toolkit>cd-dvd speed>Run test>all’ and place a burnt or pressed dvd(not a blank) disc in the drive. Your burst rate should be at least 22mb/s and your transfer rate graph should be a smooth curve.

Here is another quick link that roughly explains PIO/DMA/UDMA, but, quickly,PIO is an outdated and slow method of data transfer within your computer. DMA is faster and UDMA is faster still. There are tons of reading on the subject if you wish to google for it.

Hope this helps, let us know how it goes…


Ok, thanks. This is very helpful & now I can relate it to my hard drive 80 wire cables using DMA. My objective is to get the secondary devices to also use DMA However, my Sony DRU710A shipped with a 40 wire connector. They said I should use their connector, but since it looked exactly the same as what I had previously for my CD/Zip drive I didn’t replace it and now after throwing it into a box of cables, I can’t be sure which is theirs vs the other 40 wires I’ve accumulated. Why would they ship a 40 wire if it won’t work?

Also, they said only the 710A should be on the secondary channel. I also have a zip drive. Could that be messing things up?

I feel Charles & I are the right track if these last items can be cleared up. But I continue to think Sony and Nero web sites & in their ship documentation both need to clarify this as it seems the 710A should work right out of the box without having to find the answers. Most people won’t know how to get to a board or support web site & I imagine wind up sending the unit back to the seller

Thanks again & regards, Ron


@ cove3
hey the zip drive makes a difference. If that is on the same IDE channel as your burner, then remove one or the other. Theoretically, the IDE channel defaults to the lower speed rating of the two drives attached and zip drives are ‘PIO-only’, but it doesn’t always happen that way in practice.

Using a drive with a 40-wire cable is out-of-spec for the UDMA4 level the drive is capable of achieving. However, that doesn’t mean it won’t ‘work’, you just may have problems or you may not(if you are lucky). The 80-wire cable has 40 extra wires(not pins)between each pinned-wire for noise separation due to high-speed data transfer. This is the spec for UDMA4 where speeds are up to 66mb/s. The UDMA2 spec is for speeds up to 33mb/s. You can try the SONY-supplied cable and see how that goes. Try the drive alone on the ide channel first. Don’t attach the zip to that channel! Let us know how it goes.


Ok, I removed the zip drive on my winxp system and found I could set device manager to DMA and get both Backitup and InCd to work with the 40 wire cable in my system for the old CD and Zip drive. I guess I’ll throw the Zip drives away, as it’s obsolete technology now with the rewritable 710A.

I bought another 710a (D22 oem w/o the cable/swfe) & installed it on my Win98 system for compatability. I’m using the old cable. This also had a zip which I disconnected. Here BackitUp will burn ok with either DMA or PIO but InCd freezes on large files with either DMA or PIO despite zip being disconnected .

There’s a computer show tomorrow. I think I’ll get a couple of 80 wire connectors to be on the safe side and try that. It seems to me Sony should be shipping the DRU710A with 80 wire connectors, though. I’ve emailed them but haven’t heard back yet

Regards, Ron


@ cove3
thanks for the feedback and update as it may help others in a similar situation:). Let us know how it goes…


ATA 33 = 33mb per sec tranfer
ATA 66 = 66 m per sec transfer
ATA 100 = 100 mb sec transfer
Make sure u buy a cable rated at speed needed,a long time ago ??? because of bios limits and motherboard bus limits one channel slowed down the other, now with new boards and right cables doesnt make any difference,ditch the cables that came with drive and buy 100 ATA rated for all drives.