RE: Dave McKenzie's UNDELete utility - a LifeSaver!

> From: Dave McKenzie
> 
> The modified machine instruction in UNDELM is in the VMCRD subroutine
> (showing its CISC heritage: VMC was the "vertical microcode" on
> CISC--what is called SLIC, System Licensed Internal Code, on RISC).

This is interesting stuff for me, Dave.  I remember the terms vertical
and horizontal microcode, and I never quite understood which was on top
of which, and why.  I understood that they provided the
software/hardware isolation that has done us such service over the
years, but not the exact mechanism.  And now with the SLIC, I am less
sure as to how that works.  Would you care to share a little more of
your wisdom with a layperson?

<grin>

Joe