z80

Portable devices of early 80s were intended only for strong people because carrying a 12-kg computer was definitely not for everyone. This “luggable” was equipped with 4-MHz Zilog Z80, ~120kB of RAM and two 5.25” floppy disk drives which made it a standard CP/M machine. It was cleverly designed with a sturdy case where all ports and vents were covered (this was not typical for its competitors). There were also cool features like an easy way to load a different character set and a fast video circuit with dedicated video RAM.

Although Osborne Executive can display 80 characters per row the CRT screen is so small that longer work is not very comfortable. I don’t like the screen much not only because of letters with size of few millimeters but also because I see heavy flickering. This is definitely not a long persistence screen. Fortunately, you can attach an external screen using (monochrome) composite video output which can work with both standards (software selectable) – PAL 50Hz and NTSC 60Hz (NTSC looks better because of higher refresh rate).

The keyboard provides good tactile feedback and with an external screen attached you have no-compromise CP/M compatible computer. I don’t see this very portable but there were different standards back then. It was nice to have a way to transport a computer in a single package.

Infoworld resources: Osborne Executive ad, “When Your Micro Becomes an Orphan”