On 2015-09-18 15:33, tony duell wrote:
Are there any computers that do let you put microcode into RAM
now-days.
"Now-days"? There are some that do that, some of which are still in
operational shape. Some VAXen, in particular, have something called
"writable control store", which is essentially microcode RAM.
As far as I know, the VAX11/730 (There is one next to me waiting for me to have
time
to restore it) has the microcode entirely in RAM. Classic PERQs (3 in the next
room) have
their microcode entirely in RAM too (in that case, there is a microcode boot
ROM to load
the microcode from disk, but it is switched out after the microcode is loaded).
While we're listing things, the VAX-86x0 have the microcode in ram. It
is loaded from an RL02 at power up, by the PDP-11 front end.
Johnny
