I happen to have a large number of machines that are old and some are even 
slow.  They do many jobs becuase if for anything else they work well. 
Now by current standard a z80 at 4mhz is positively glacial but it runs 
the best software for docs that I happen to like (runoff).  

=:The older VAXen are not computational speed demons, but they are pretty 
=:darn good at handling a bunch of I/O. I've got two CXA16's in my 3800 and
=:can drive 32 terminals at once with them. This in turn lets you give an 
=:entire class access to "the computer" at the same time. Basic computer 
=:science can be learned on any machine and frankly I think learning on a VA

I've done this with a MVII to teach Pascal to a small class (12) on DHV11s
and it wasn't even straining and I still had 4 spare terminal lines unused.

Another class used a MVII and 8 VT1200 xterms running decwindows back when 
PCs were hot if you had a 486dx/33 and 8mb ram running Win3.1.

=:I've also got a couple of PDP-11's and a couple of PDP-8's each easier to
=:understand the next. So a complete soup to nuts computer literacy program
=:can be taught with just three architectures.

They are kinda neat.  I have 11s and 8s as well.  I happen to like the 
PDP-8 for it's minimalist instruction set.

Allison