The museum published the software yesterday, following up on its earlier release of the source code underlying Apple's original MacPaint.
Source code is what humans write -- in Photoshop 1.0's case the brothers Thomas and John Knoll. The initial Photoshop is written in written 128,000 lines of code, a combination of the high-level Pascal programming language and low-level assembly-language instructions. When converted to machine code, the program was small enough to fit on a floppy disk.
Photoshop started in the 1980s as a personal project the brothers called Display, but they started trying to commercialize it, according to the museum's exhibit. Their first success was version 0.87, which scanner maker Barneyscan called Barneyscan XP, but Adobe Systems agreed to a deal in 1989 and distributed Photohshop 1.0.1 in 1990.
Photoshop 1.0.1 dates from a time when many computer screens were small and could display only black or white pixels -- not even gray. And of course image processing is very taxing for computer chips. Although today's large, color monitors are very different, Photoshop still pushes computer processors about as hard as they'll go.
Of course, new types of museum exhibits mean things change for those perusing the exhibits, too. In this case, it's a 1,400-word license agreement to see the Photoshop source.