I have had many engineers and customers ask me about the basic differences on DMX and DMX2 machines. Based on some data I had put together a while back, here are the major differences on a DMXxxxx vs a DMXxxxx-P2 vs a DMXxxxx-M2-3, etc. 

The number of drives per loop: the lesser the drives on a single loop the better the performance. There are two different versions of drives per loop: one being the 9 drives per loop and the other one being 18 drives per loop. 

Following are all 18 drives per loop

DMX1000:   

Low Performance, 
1st Generation DMX, 
18 drives per loop, 
Single Bay with Single Phase power, 
144 drives max. 

DMX1000-M2:           
High Performance, 
2nd Generation DMX, 
18 drives per loop, 
Single Bay with Single Phase power, 
144 drives max.

DMX2000:                 
Low Performance, 
1st Generation DMX, 
18 drives per loop, 
Dual Bay with Single Phase power, 
288 drives max. 

DMX2000-M2:           
High Performance, 
2nd Generation DMX, 
18 drives per loop, 
Dual Bay with Single Phase power, 
288 drives max.

DMX2000-M2-3:        
High Performance, 
2nd Generation DMX, 
18 drives per loop, 
Dual Bay with Three Phase power, 
288 drives max. 

DMX3000-3:              
Low Performance,  
1st Generation DMX, 
18 drives per loop, 
Triple Bay with Three Phase power, 
576 drives max . 

DMX3000-M2-3:        
High Performance, 
2nd Generation DMX, 
18 drives per loop, 
Triple Bay with Three Phase power, 
576 drives max.

Following are all 9 drives per loop

DMX1000-P:              
Ultra Performance, 1st Generation DMX, 
9 drives per loop, 
Single Bay with Single Phase power, 
144 drives max. 

DMX1000-P2:            
Ultra Performance, 
2nd Generation DMX, 
9 drives per loop, 
Single Bay with Single Phase power, 
144 drives max.

DMX2000-P:              
Ultra Performance, 
1st Generation DMX, 
9 drives per loop, 
Dual Bay with Single Phase power, 
288 drives max.

DMX2000-P2:            
Ultra Performance, 
2nd Generation DMX, 
9 drives per loop, 
Dual Bay with Single Phase power, 
288 drives max. 

DMX2000-P2-3:         
Ultra Performance, 
2nd Generation DMX, 
9 drives per loop, 
Dual Bay with Three Phase power, 
288 drives max. 

Machines are categorized as a DMX and DMX2, The ones above with a P2 or M2 are DMX2. 

The new generation of DMX machine’s now available in the market are: DMX-3 and DMX-4. This blog article only talks about the DMX and the DMX2′s. 

Related posts:

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3. EMC Symmetrix, 20 Years in the making
4. DMX, DMX2 and the Early days of Symmetrix
5. Clariion Basics: DAE, DPE, SPE, Drives, Naming Conventions and Backend Architecture
6. EMC Symmetrix and DMX Serial Numbers