Conference turris::microvax

4354.0. "Quad MicroVAX 4108 & HSD50s" by BEET::EAGAN (Among the fashion impaired...) Fri Mar 14 1997 17:12

	I am in the preliminary stages of working a config for a customer.
	If the issues I'm asking have been already covered in the notesfile,
	woops.  I did search titles for "HSD50", "HSD30", "4108" and "quad".
	Came up empty.   I have also read the SOC for the 4108 and there's
	no info on connecting HSD30s or 50s.  There's no info (at all) on the
	HSD50 in the SOC (on-line variant).  So... I look to y'all for help!

	My customer has a VAX 4000 M106 on order.  He's looking to add
	3 more.  We have discussed, and probably swayed him towards, the
	M108, as it can be rackmounted easily.  He wants to have lots
	of storage and has settled on the HSD50 (redundant).

	My problem is I can find precious little config info in the SOC
	re: doing this.   Cables I'd use are of concern.

	Also, I'm concerned that I've used up all 8 addresses on both
	busses.  This is probably OK.  But, can we switch which bus the
	internal HSD is on (see my drawing).  I am not too sure how the
	device naming would work and want to make sure its OK.

	Guidance appreciated.




  4000 106/8           4000 M108            4000 M108            4000 M108
+-----------+        +-----------+        +-----------+        +-----------+
|           |        |           |        |           |        |           |
|HSD        |        |HSD        |        |        HSD|        |        HSD|
| A       B |        | A       B |        | A       B |        | A       B |
+-----------+        +-----------+        +-----------+        +-----------+
  |       |            |       |            |       |            |       |
  |       |            |       |            |       |            |       |
  |       |   +-----+  |       |            |       |   +-----+  |       |
  |       +-->|HSD50|< | ------+----------- | ------+-->|HSD50|< | ------+
  |           | --- |  |                    |           | --- |  |
  +---------->|HSD50|<-+--------------------+---------->|HSD50|<-+
              +-----+                                   +-----+

        You do not have to switch the internal cabling. Just connect to
        cables externally in needed way.
        
        In first common DSSI bus:
        
        VAX1/A-HSD10 -- VAX2/A-HSD10 -- VAX3/B -- VAX4/B -- HSD50 -- HSD50
          7      0        6      1        5         4         2        3
        
        In the second DSSI bus:
        
        VAX1/B -- VAX2/B -- VAX3/A-HSD10 -- VAX4/A-HSD10 -- HSD50 -- HSD50
          7         6         5      0        4      1        2        3
        
        with the next line showing suggested DSSI id settings.
        
        
        I do not see any problem with device namings. Just make it
        logical.
        
        _veli
        

    Hi, 
    
    Could someone confirm if a Quad host DSSI configuration was qualified
    on the MicroVAX/VAX4000 range. Last time I looked at the SPD it only
    stated VAX6000/7000, has this now changed??
    
    Many thanks,
    Colin S.

	Well, I had kind of forgotten to check that angle... 

	This is what I took my starting point from... the OpenVMS Cluster
	SPD 29.78.10 (6.2):

	"The maximum number of CPUs that can be connected to a DSSI is 4,
        regardless of system or adapter type. Any mix of systems and
        adapters is permitted. Depending on the CPU model, it may not be
        possible to configure four CPUs on a common DSSI bus because of
        DSSI bus cable-length restrictions. Refer to the specific CPU
        system configuration manuals for further information."

	I have not gotten to the CPU Sys Config Manual for the VAX 4000.
	If that's on-line and someone has a pointer, I'd sure appreciate it!