This month’s Hobby Tech feature takes a look at the recently-unearthed Nine Tiles prototype ROM for the ZX Spectrum by installing it on a ZX Spectrum Next, dramatically improves the flexibility of the FLIR ETS320 thermal inspection camera, and pores over classic computer commercials courtesy of coffee-table tome Do You Compute?.

First, the prototype ROM. In my review of the ZX Spectrum Next in Custom PC Issue 202, I mentioned that it’s possible to create new “machine personalities” – both by replacing the read-only memory (ROM) files used in Spectrum mode and by loading new cores onto the FPGA at the machine’s heart. Shortly prior to the ZX Spectrum Next’s launch, the Centre for Computing History received a trove of artefacts from Nine Tiles – including a prototype ZX Spectrum which was used to develop a ROM which never actually made it onto the publicly-launched machines.

The Centre had negotiated to make the ROM image available for free download for educational and academic purposes, which gave me an opportunity to load the ROM onto the ZX Spectrum Next and create the Nine Tiles Prototype as a usable machine personality. What followed was a process of debugging and reverse-engineering in order to make the ROM functional on the Next – a process which, I’m pleased to say, was wholly successful.

The FLIR ETS320, meanwhile, was reviewed back in Issue 201 – and one of my biggest complaints was its incredibly short focal length, meaning that it is only possible to analyse a very small part of a given circuit board under the thermal sensor. While the camera platform is capable of rising up, anything above 70mm away from the device on test is too blurry to be of use – unless, that is, you take advantage of a 3D-printed tool to manually adjust focus. The improvement is stark, as thermal images published in the piece demonstrate.

Finally, Do You Compute? is a book which looks not at the history of computing but at the history of selling computing – specifically, as the subtitle makes clear, “from the Atomic Age to the Y2K bug.” Put together by Ryan Mungia and Steven Heller, the book is a fantastic chronological walk through the shift in computers being for governments and big businesses to any businesses and eventually the home user.

It also has a major flaw, and it’s not one caused by the authors: Apple, for reasons unspecified, declined to provide permission for its adverts to be reproduced in the book. With Apple having been at the very forefront of the personal computing revolution, and well-known for iconic adverts from its 1984 Superbowl commercial to “Think Different” and “Rip Mix Burn,” it leaves a real hole in the book.

Custom PC Issue 206 is available now in supermarkets, newsagents, and online with global delivery via the official website.