Printing Graphics From BASIC
Ben Ryves patched BASIC to print graphics from the late 1980s Cambridge Z88 notebook computer to a Serial 8056 printer.
Bringing vintage computing hardware back to life may not serve much practical purpose in terms of modern productivity, but it provides a unique challenge for enthusiasts. The process of diagnosing decades-old components, sourcing rare replacement parts, and mastering obsolete operating systems offers a hands-on historical education that is deeply satisfying.
Despite their age, these machines are typically highly repairable because, unlike today, manufacturers routinely released everything from datasheets and circuit diagrams to source code for the benefit of owners of the hardware. Not only that, but everything was much simpler decades ago, which meant that understanding the inner workings of a personal computer was achievable by anyone with a little patience.
A big problem
Ben Ryves is a retro computing enthusiast with a Cambridge Z88 notebook computer from the late 1980s. Ryves has long wanted to print graphics from this machine, but has not had an appropriate serial printer to do the job. So when a vintage Serial 8056 printer (also known as the IBM PC Compact Printer) came up for sale at a low price, Ryves snapped it right up.
However, this printer purchase is a reminder that everything was not easier back in the day. A lack of standards and compatibility issues, in particular, were common problems at the time. In the case of the Cambridge Z88, only Epson-compatible printers were supported. The Serial 8056 is not Epson-compatible, so attempting to print graphics with it only produces garbage.
A BASIC solution
Rather than call it quits, Ryves disassembled the BASIC patch that gives the Z88 the ability to print graphics. After locating the relevant routines in the Z80 assembly code, it was discovered that supporting the Serial 8056 printer was just a matter of updating the character codes and line feeds that get transmitted via serial to be compatible with it, rather than Epson hardware.
More details about the patch itself, the source code, and how to use it are available in the project write-up. Go grab it if you are itching to print off your own Z88 artwork.