> Anders Magnusson wrote:
> > 
> > A MicroVAX II with 
> > error-free RA disks on KDA50 and DELQA are a much better choice.
> 
>   Are the stability problems with DEQNA hardware-related or driver-related
> What are the essential differences between the two (I've only ever see a
> DEQNA).

Essentially none if you have a good DEQNA.  Problem is they went through
many major revisions and 12 minor ones to fix problems. The DELQA
is more reliable and faster internally.  My uVaxII has a C1 rev DEQNA that 
has proven bullet proof, it's outlived two DELQAs.

The devices <be they disk or network> are easily blamed but it's the drivers
responsibility to resolve errors and determine error recovery if possible.
For something like the NI device unless the device failed completely any
problems are clearly the driver.  The VS2000, it's hard to blames the MFM 
drives <short of faailure> as they did and do run VMS just fine.  Again the
driver is weak as we know it doen't do BBR an essential activity for any 
hard disk where it's not made invisible in the drive.

Also to me stability is present when a copy of software can be put on 
several systems of typical configuration and the results are the same.
For the uVaxII that may be true but the VS2000 port clearly has device 
issues as it's the same CPU chip.

Allison