On Tue, Jan 23, 2018 at 10:35 AM, Mark Kahrs via cctech < cct...@classiccmp.org> wrote:
> A few notes: > > The experimental Ethernet speed was in fact 2.94 MHz: It's the Alto clock > divided by 2. > > The Alto based printer was called "SLOT" -- Scanning Laser Output > Terminal. It was plugged into the Alto backplane and presented itself as a > hardware peripheral controlled by microcode (as was the case for all Alto > I/O). It was an Alto task, of course. > There was also the later Orbit controller, which talked to a number of ROS (Raster Output Scanner) devices, including the Dover. The Orbit controlled the ROS and the printer and had special hardware + microcode to assist in the generation of raster bands (16x4096 pixels) for imaging. This allowed the Alto to keep up with the Dover (which was approximately 1 page/second) in real time while generating 384dpi output. (Incidentally, not all Alto I/O was implemented as hardware + microcode -- just the high-bandwidth stuff; there was memory-mapped hardware at the top of the address space for keyboard/keyset/mouse and various other devices.) Also: The latest version of ContrAlto ( https://github.com/livingcomputermuseum/ContrAlto) emulates the Orbit and Dover ROS in case anyone's itching to print some PRESS files :). Bitsavers has a set of disks I put together with Spruce (one of a number of Alto-based print servers) if you want to play around with it. - Josh