How many hardrives can you have?

Vince604

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How many hardrives can you have for a computer? If using a SCSI controller and SCSI hardrives how many can you have at the same time on one computer?
 
Trying to remember from my hardware course 3 years ago. 15 drives I think. 0-15 addresses. 7 is reserved as the system address or something.

Someone is soon going to shoot me down here.

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Toejam31

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A high-performance RAID array can have between eight and fifteen disk drives attached to a single channel. Include a dual channel controller and the total array can be up to 30 drives.

<A HREF="http://www.pcguide.com/ref/hdd/if/scsi/summary-c.html" target="_new">Summary of SCSI Protocols and Transfer Modes</A>

The Host Adapter counts as one device.

You did good, camie!

Toejam31

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Toejam31

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<A HREF="http://www.pcguide.com/ref/hdd/perf/raid/index.htm" target="_new">Redundant Arrays of Inexpensive Disks (RAID)</A>

Happy reading! :wink:

Toejam31

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<font color=purple>"Procrastination on your part does not constitute an emergency on my part."</font color=purple>
 
RAID is the logical combining of two or more drives into an 'array' which, depending on the array you have specified will serve a particular purpose.

RAID 0 combines usually two drives into one logical drive. This gives increased performance, but lacks redundancy.

RAID 1 Usually two drives again, one mirrors the other for data integrity. Max redundancy for a slight loss of performance.

RAID 0+1 combines both above, but requires 4 drives.

Other forms of RAID exist, and I'm sure Toey or some other helpful soul will provide links. Bottom line is RAID = more drives = more cost.

As to the hotswap stuff, I believe that's RAID...5? Hmmm. Not sure. Tends to be for server usage. Another rule...the more secure and convenient it is, the more expensive it is.

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Crashman

Polypheme
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I have a three channel Utlra 80 card that supports 45 drives and up to 3 controllers (so If I needed more than 45 drives, I could use up to 135 drives on three controllers, plus IDE). But right now my single card supports 45 drives. I'm not even using that card right now and have only 7 drives (all my case supports).

What's the frequency, Kenneth?
 

Toejam31

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Questions, questions.

:wink:

Let me sneak in here again!

<A HREF="http://www.pcguide.com/ref/hdd/perf/raid/concepts/gen.htm" target="_new">General RAID Concepts - Physical and Logical Arrays and Drives</A>

RAID can be either IDE or SCSI.

<A HREF="http://www.pcguide.com/ref/hdd/if/scsi/index.htm" target="_new">Small Computer Systems Interface (SCSI)</A>

Again, happy reading!

Toejam31

<font color=red>My Rig:</font color=red> <A HREF="http://www.anandtech.com/mysystemrig.html?rigid=6847" target="_new"><font color=green>Toejam31's Tantalizing Tantric Toy</font color=green></A>
<font color=red>Second Rig:</font color=red> <A HREF="http://www.anandtech.com/mysystemrig.html?rigid=15942" target="_new"><font color=green>Toey's Dynamite DDR Duron</font color=green></A>
____________________________________________________________

<font color=purple>"Procrastination on your part does not constitute an emergency on my part."</font color=purple>
 

Vince604

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Haha thanks toejam. Got the SCSI part but RAID too confusing already. It's something like a whole bunch of drives acting as one or something. Don't get RAID and don't think going to really need it. But thx again!
 

Crashman

Polypheme
Former Staff
RAID is a term used to describe an array of disk. Level 0 is where all drives are accessed simultaneously as one, giving you mutiplied transfer rates.

I don't feel like explaining everything RAID right now, I suggest you look through the forums.

What's the frequency, Kenneth?
 

kief

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RAID 0 is "striped" giving you "mutiplied transfer rates". RAID 1 is "mirrored" for data security.

Jesus saves, but Mario scores!!!
 
G

Guest

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<A HREF="http://www.anandtech.com/guides/viewfaq.html?i=110" target="_new">Here
</A> is another explanation of raid, somewhat shorter (and simpler?) than PC-guide's.


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