Tony Duell ard at p850ug1.demon.co.uk
Fri Jan 9 13:59:09 CST 2009

> You can probably make do without REN, too.  The PET has it tied to 

There would be no reason for the disk unit to _drive_ REN (or to drive 
ATN or IFC for that matter), since the disk unit will never be a 

I am not sure if HP disk units need to be able to read the state of REN. 
Certainly HP machines do use it, but I can't think of any good reason why 
a disk unit would want to be not controlled remotely.

> ground, i.e. permanently asserted, for a start.  Just assume it's 
> asserted and you won't go far wrong!

Be careful making assumptions like that if you're talking to HP machines. 
HP wrote the stnadards for HPIB, and they also have been known to bend 
them :-). I am told for example, it's impossible to use a 9914 HPIB chip 
in an HP-compatible drive unit (althoguh it can be used -- and was used 
by HP -- in a computer to talk to said drive units).


More information about the cctech mailing list