What is CNR/IDE RAID?

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eddy05

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Guys if I may trouble you again... I'm reading reviews about motherboards, and I saw the words "IDE RAID." What is it and what it does?

I looked at my own motherboard [ECS P4ITA2] and saw a "CNR" slot. It wasn't used up. What is it for? How much is its bandwidth?

Sorry for asking all this kind of questions coz' I'm a newbie to hardwares.
 

boeingfixer

Posts: 1,006   +0
Hey eddy05,

Great question. SVT is only part right on the RAID issue. Raid stands for Redundand Array of Inexpensive Drives. Raid allows you to take two drives (hopfully identical size and type ) and double their space and speed. It works like this. Two 40 gig drives = 80 gig. But in raid, you can set the drives to be stripped (0) or mirrored (1) or a combanation. In stripped, two drives alternate info, so if you had a single drive and wanted to write 1 2 3 4 5 6, it would write all the numbers to one drive, but stripped writes (at the same time) drive 1 1 3 5, drive 2 2 4 6, it splits the data and writes it to alternating drives, but windows only see's one big drive.

Mirrored just makes a duplicate of the first drive, so if one drive fails, you just swap the drives and reboot. For us enthusiats, we go for the RAID 0 for best performance.

Now a CNR stands for Communications Network Riser, and SVT is 100% right. I could go into an explaination but it is a waist of time and you most likely will never use it, as aftermarket CNR devices are very few and far between.
 

boeingfixer

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So look for a RAID board if you want. It allows you to have 8 channels for IDE instead of the standard 4. You can put all your CD-Roms CD-r's DVD and what not on one set of channels and your Hard drives on their own dedicated FASTER bus, as most of the RAID IDE channels are either ATA-100 or ATA-133. Hope this answers some of your questions. ;)
 

SuperCheetah

Posts: 704   +1
The sticky right above your post will give you lots of info. and links about raid and its advantages. I highly advise you to check it out!

And as boeing explained, RAID is for making two hard drives faster than one would be. I have a raid setup on my system and I like it alot. The only disadvantage is that it only really increases the read access time that a hard drive has and not much else. Still, if you have the money this is definitely a good way to go.
 

boeingfixer

Posts: 1,006   +0
Originally posted by SuperCheetah
There is also a way to make software raid. It is explained throughly here:

http://www4.tomshardware.com/howto/01q3/010906/index.html

Neat little trick if you have the drives but no board raid.
Ahh but if you read alittle further....

So far, everything sounds very promising. However, we found that there is no way to run Windows 2000 itself on a software RAID array. After setting up a RAID array specifically for installing Windows 2000, the setup program did not recognize the stripeset drive. A possible reason is that the standard drivers do not support Windows 2000's dynamic drive model. If you still choose one of the RAID drives to install the OS, Windows 2000 will prompt you to format it.
The cost of a third drive would be greater than a board with the RAID controller build in. If you had 3 drives, like I do, this is a good alternative, especially if you want RAID and don't want to add any additional hardware or you have already bought the parts. But if you are going to buy new, get one with RAID.
 

SuperCheetah

Posts: 704   +1
I know boeing, I was just suggesting if he had lots of drives that happened to be laying around he could try it, for what reason I don't know ;). It sounds complicated to me, but they seem to get good results from it. I would also go with the onboard raid or a controller card if I were you.
 

eddy05

Posts: 147   +0
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Great Info

Though it sounds terribily complicated to me. What I think I know is:

RAID is an arranging of your hard disks so that 2 hard disk can be read as only 1 partition.

RAID usually increases performance compared to 2 hard disk on 2 channels and on 2 separate partitions.

Different capacities of hard disk can be used, but RAID only allows the capacity of the smaller disk, multiply by 2.

RAID requires a special motherboard, though RAID in Win2000 by software is possible.

Hmm... can I ask again, if you wanna RAID 2 HDD's together, do you need to set it with a software (ie. Fdisk) or just plug the HDD in and it'll detect as RAID automatically? Do you need to set any switches on your motherboard?

What is SCSI? I couldn't find it on my Motherboard.

Edited: Okay I re-read boe's reply again and understood RAID 0 and RAID 1! RAID 0 seems efficient, but if one drive fails, isn't the whole system corrupted? (Which is why all of you wanted a VERY secure HDD for RAID 0?) RAID 1 seems to be a waste of space, but it works just like Norton Ghost except it deals with hardware :D
 

boeingfixer

Posts: 1,006   +0
Ok Edd,

Yes in RAID 0 if one drive fails, your stuck. You have to start over.

And the answer to your other question is yes and yes. You need software to control RAID, basically a driver for windows to see it as a RAID drive. And yes in some cases you have to set a jumper. On my board, I have 2 IDE/RAID (4 devices) to put them in RAID I just move a jumper over. If I want standard ATA-100 with NO RAID, I move the jumper back. When you set up lets say Win XP, you have to have the RAID driver on a disk (floppy). During the start of the install it asks you for any third party SCSI/RAID drivers. You put the disk in and poind XP to it. Then it asks you to set up your RAID. It is very easy. On my board, when RAID is enabled, you get a special RAID menu that lets you set up your RAID. You do this before you start to load XP. Yes you still have to Fdisk but windows and your RAID utility take you right thru it. I did mine in about 2 hours. Wasn't hard at all.

And yes RAID 1 is kind of like Ghost but lets say Ghost on the fly. Because it is always making a duplicate of your primary master hard drive. This is useful in servers. Let's say 3DS is running on a server with RAID 1 and a hard drive fails/chashes, all the operator has to do is switch the 2 drives and reboot the system and your back up again. In some servers with hot swappable drives, you don't even have to do that, it will automatically switch to the good drive.
 

SuperCheetah

Posts: 704   +1
From the good guys at www.whatis.com:

SCSI- (pronounced SKUH-zee and sometimes colloquially known as "scuzzy"), the Small Computer System Interface, is a set of evolving ANSI standard electronic interfaces that allow personal computers to communicate with peripheral hardware such as disk drives, tape drives, CD-ROM drives, printers, and scanners faster and more flexibly than previous interfaces. Developed at Apple Computer and still used in the Macintosh, the present set of SCSIs are parallel interfaces. SCSI ports are built into most personal computers today and are supported by all major operating systems.

In addition to faster data rates, SCSI is more flexible than earlier parallel data transfer interfaces. The latest SCSI standard, Ultra-2 SCSI for a 16-bit bus can transfer data at up to 80 megabytes per second (MBps). SCSI allows up to 7 or 15 devices (depending on the bus width) to be connected to a single SCSI port in daisy-chain fashion. This allows one circuit board or card to accommodate all the peripherals, rather than having a separate card for each device, making it an ideal interface for use with portable and notebook computers. A single host adapter, in the form of a PC Card, can serve as a SCSI interface for a "laptop," freeing up the parallel and serial ports for use with an external modem and printer while allowing other devices to be used in addition.

Although not all devices support all levels of SCSI, the evolving SCSI standards are generally backwards-compatible. That is, if you attach an older device to a newer computer with support for a later standard, the older device will work at the older and slower data rate.
You usually need to buy a SCSI card to plug into one of your PCI slots to use this method. It is supposedly faster than RAID, but the downside is that it is fairly expensive. The two use the same concepts though.

Good post boeing, my setup was the same way. If you have RAID on your mobo then it will come with some basic drivers for the raid setup, although I recommend getting the latest ones from the manufacturer, and the motherboard will have a built-in chipset for controlling your raid setup. The setup is really easy and making the raid array isn't very hard either. Post back if you want further information!!! Hope this helps. :)

Edit: Here is a site explaining some of the lesser known types of raid like Raid 5, 10, etc.

http://www.computerhope.com/help/raid.htm
 
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