What good is a single channel ATA RAID controller?

[BCinSC]

SOYO board I have has built in HPT371 controller. Doubt it has any cache, certainly not battery backed, thus what value?

 

[SunSamurai]

" If ATA can only write to master OR slave, not both at same time?"

Whomever told you that is a dumbass.

 

[BCinSC]

Um, it's in the spec? Been true since the dawn of IDE? Dual Channel ATA RAID has value because you can actually write to two drive simultaneously.

 

[Zepper]

"Remain silent and be thought an idiot OR speak out and remove ALL doubt..."

You are correct BC, only one IDE drive per channel can operate at a time. Perhaps that is why SATA went with one drive per channel as they would have needed only to add a drive select wire to the spec to allow two drives per channel just like PATA. If at all possible, I set up my systems with only one IDE drive per channel for best performance - even if I have to buy a controller to do it. I suppose RAID-1 (mirroring) is possible on one channel, but I would think it would be impossible to do RAID-0 where different data has to be able to be written to each drive at the same time. All the add-on adapters I've seen do the RAID-0 cross-channel and RAID-1 on the same channel.
.bh.

 

[superkdogg]

Ok, so I'm an idiot. Does this thread say that for best IDE Hard Drive to Drive copying performance, the HDD's should be on two different controllers? I for some reason (bad information years ago) have always had both HDD's on the same cable and both Opticals on the same cable. I was told that having optical and HDD on the same controller could slow down the HDD. Should I be installing a CD and an HDD on one controller or both HDD's on the same and the CD's on their own as well?

 

[MechEng]

IDE/ATA Configuration and Cabling

Master/Slave Channel Sharing: By its very nature, each IDE/ATA channel can only deal with one request, to one device, at a time. You cannot even begin a second request, even to a different drive, until the first request is completed. This means that if you put two devices on the same channel, they must share it. In practical terms, this means that any time one device is in use, the other must remain silent. In contrast, two disks on two different IDE/ATA channels can process requests simultaneously on most motherboards. The bottom line is that the best way to configure multiple devices is to make each of them a single drive on its own channel, if this is possible. (This restriction is one major disadvantage of IDE compared to SCSI). An add-in controller like the Promise "Ultra" series is a cheap way of adding extra IDE/ATA channels to a modern PC.

Also this site have some extensive info on these matters. If not in any articles, then some of the people that hangs out there knows...
They have helped me quite a few times in the not so distant past...

EDIT:
superkdogg:
It depends on what you are using your drives for I think...
If you want to copy CD's for example, your best bet is to have the burner on one channel, and the cd-rom/HD on the other channel.
For my use I have my system (WinXP) on one HD and my games/data on other HD's, in order to separate the data requests across both IDE channels. I also keep my cd-rom and my burner on separate channels for the reason stated above.
Whether having a cd-rom on the same channel as a HD slows down the HD... I think it only slows it down if your using the cd-rom at the same time, but that would also be the case if you were using another HD on the same channel. The slow-down when paired with a cd drive may be larger because of the cd drives higher seek times, but this is pure speculation on my part. Someone else around here propably has more knowledge than me about these matters...

 

[montag451]

try and put an ide hdd as master on each channel.
with an optical Slave on each channel - will get better cd copying experience, and faster hdd activity - though, not as good as just having a single device on each channel.

 

[SunSamurai]

I dont give a damn what the spec says. technically its true, but technically 1Gb eathernet should transfer at one Gb.

I have had RAID0 on two drives master/slave. There is NO PREFORMANCE DIFFERNCE by haveing two drives as master/master or slave/master. The only differances happends when you get to three + drives.

 

[BCinSC]

Are you confusing Master/Slave with Single/Dual channel? There should be a difference between 2 drives on one channel as Master and Slave versus each drive on own channel (whether they be Master or Slave of respective channel making a difference is less definitive)

 

[Pariah]

An ATA channel is not limited to the throughput of one drive. Just because a drive is constantly active doesn't mean the channel is locked the entire time. It is possible to achieve 85-90MB/s on a single ATA100 channel which is well beyond the capabilities of any single PATA hard drive. You'll get better performance from seperate channels, since two current PATA drives can achieve about 120MB/s peak, but it's a myth that having 2 drives on one PATA channel limits the combined performance of them to one drive.