VT78 - lots of questions - test-drb@ccmp.vtda.org

30 Dec 2000

From: Jeff Hellige &lt;jhellige(a)earthlink.net&gt;

...
  The DECmate II is an interesting beast, but
unfortunately it
shares the hardware incompatabilities of the original DECmate, though
it 'improves' on them.  I have a II that is pretty loaded, with the 

One that it makes worse is the terminal emulation.  Terminal interrupts
are not supported in the same way as is TTY at 03/04 so the KL8e
emulation is poor except for the most simple programs that poll
the IO.

The improvements is 32KW of ram (32kw for pannel mode as well)
the possibility and support for a hard disk is nice.  It's also faster
though the DMIII is fasest of the lot.

...
 working again.  It sounds like from a software
compatability point
that the VT78 might be the better choice for a micro able to run
standard PDP-8 stuff. 

It's closer but the RX01/2 IO is somewhat different than the omnibus
companions.

Also the chip versions while very close to PDP-8 are not exact for timing
and OPR/ IOT instruction microprogramming is slightly different.

Allison