> anyone could examine benefits of these models and on which 
> one i should focus
> and fill it with components from another ones? i have only 
> one graphics
> card/monitor. i like that 2cpu AV530 but it looks older than 
> those AV4x00. i
> am tryingo to get some documentation and DG/UX media now (i 
> hope NetBSD will
> be ported soon :)

Umm, don't hold your breath... ;-)

> another problem i have is that i have no root access on these 
> machines. they
> are from competitive upgrade and there is DG/UX installed but 
> i am not able to
> get into. how do i break boot-up process and boot into single 
> user? is there
> any shortcut to fell into firmware/break booting? i saw on one of them
> (probably broken hdd there) that if it could not boot from 
> default device, it
> fell into firmware but i could not get there on machine with good hdd.

Start it going, then when it's doing its startup tests, fiddle with the
reset switch on the back.  It should drop into the system monitor (a prompt
like "Jp#0SCM>", from memory).  Then you can tell it to boot single user
(try 'b -1', again from memory - someone else might know better).

> and next thing is cable from gc to monitor. i saw there are three bnc
> connectors on gc (RGB) and 5 on monitor (RGB and two another 
> ones, i could not
> remember how it was marked (i do not have monitor here now), 
> i think some sync)
> is somewhere schematic description for this cable or how is 
> it called bcause i
> want to use monitor, now i am logged on serial console.

Wire RGB on the machine to RGB on the monitor, and switch the monitor to
sync on green, if there's a switch.  Otherwise, just suck it and see.