Install 4 CD burners..IDE or SCSI?

[RockDog]

A friend of mine would like to instal 4 cd burners in his computer to use simultaneously. Is it possible to burn to 4 IDE cd burners at once or would I have to go SCSI? He doesn't have much money and would prefer IDE if it is possible.

Thank you,
RockDog

 

[Adul]

two threads on the same subj huh

i asnwered in your other thread in GH

 

[Peter]

Remember that IDE drives used at their maximum speed always block the channel they're on COMPLETELY. SCSI devices share bandwidth much better.

So for four burners, you'd need four IDE channels, but only one SCSI host adapter. And I guess you want reliable burners, so you need to skip the cheap stuff anyway.

regards, Peter

 

[corkyg]

You left out two viable options - Firewire and USB 2. He could also daisy chain them that way. For 4 burners - they just about have to be external. The real limiting factor is how many burners can a given burn software support at one time.

Adul is right - multiple posts of the same thread in different forums is not cool.

 

[Peter]

FireWire would be OK, USB suffers from the same problem as IDE, no real bandwidth sharing.

Besides, since practically all USB and FireWire external burners are IDE drives with adapter boards up their rear ends, you'll get the exact same channel blocking syndrome as you would when connecting to an IDE channel internally.

regards, Peter

 

[RockDog]

Sorry guys I didn't mean to break the rules or be uncool or anything. I was trying to post in the forum that I thought best fit my question but I hadn't received any replies for quite a while so that's why I decided to post in the GH.

I guess I need to be a little more patient. The last thing I want to do is disgruntle the very people who are responsible for a large part of the knowledge I have aquired to date. I have nothing but the highest respect for Anandtech and the people of the Anandtech Forums.

As you can tell by the number of posts that I have made I don't frequent the Anandtech Forums often. When I do I try to do a search for a post similar to the one I am considering so I'm not clogging up the forums. I also look to see if there are any questions that I can help answer.

The question of the 4 CD burners really belongs to a friend of mine despite the wording of the thread in GH. I suppose we will go ahead and try either the Promise controller with 4 IDE drives or 4 external USB 2.0 drives. If those don't work I guess they will be up for sale on ebay or something. We expect to give this a try in the next couple of months. If and when we do I will post the results.

Thank you,
RockDog

 

[Peter]

RockDog, please hear my point. Every technology that ends up being an IDE device, be it FireWire, USB or native IDE, does not support sharing the controller's bandwidth amongst devices. IDE drives, no matter how they're connected, block the datapath they're on 100 % until the transaction completes on the drive.

For simultaneous burning, you need true (!) SCSI drives. The reason is these can release the SCSI bus during mid-transaction idle phases, allowing the host controller to talk to other devices meanwhile.

edit: Oh, your data source (read: HDD) also needs to be SCSI. Same reason.

regards, Peter

 

[Gandalf90125]

If the data source (e.g., hard disk) were IDE, and the four burners were SCSI, then wouldn't that work better than having source and burners all on the same SCSI channel?

 

[Nothinman]

The source won't matter much if it's one file going to 4 burners, it'll be mostly read from the page cache not directly from the disk. If it's multiple files to multiple burners I'd go SCSI if possible for the low seek times of 15K RPM drives otherwise you may end up relying on burnproof more than you'd like.

 

[Peter]

There's plenty of bandwidth on a SCSI channel to handle four burners and a HDD. Besides, dual channel U160+UW SCSI cards from Tekram or LSI are _cheaper_ than Adaptec's single channel stuff, so simply get one of those, put the HDD on U160 and the burners on the legacy UW/U channel.

The main point though is that SCSI HDDs can take multiple requests and complete them in any order, which is important if there's more than one task running. IDE drives take a single command and idle until completion, only then can the system issue the next one.

Can't see what that's about? Think restaurants.

SCSI: Waiter buzzes around taking orders and sticking them to the kitchen counter. Cook does his best in multiple pans, pots and ovens, and puts a meal onto the counter whenever it's finished, with the order note attached, in no particular order. Waiter serves meals as they appear, to whoever ordered them. You can even have multiple waiters without screwing that system.
IDE: Waiter takes one order, goes to the kitchen counter to tell the cook what to do, then sits there idle until the plate with the meal turns up. Then waiter returns to the table to serve, and then takes the next order from someone else.

In an IDE restaurant, cooking time for the individual meal might be slightly shorter, serving a single guest quicker, but as soon as more folks turn up, waiting and idling times will become unbearable. SCSI restaurants have a slightly higher order handling overhead so the single guest is served very slightly slower, but they make better use of their kitchen equipment in high load situations, thus serving many guests much faster.

regards, Peter