The STACKER combines a fully upgradeable RISC OS workstation and an integrated Linux companion system in a single, compact, self-assembled enclosure. Built on the versatile DIY THREE platform and extended vertically using the PLUS FIVE module, it delivers two independent computers that operate side by side: a powerful primary RISC OS system and a dedicated Linux environment for complementary tasks. At the heart of the RISC OS side is the DIY THREE, designed as a high-performance, self-assembly RISC OS computer. It is supplied with a Raspberry Pi Compute Module configured to run at 2 GHz–2.2 GHz and backed by 4 GB of RAM. Storage for RISC OS is provided by 256 GB of NVMe SSD as standard, with a 32 GB eMMC module reserved for the operating system and boot image, all running on the FreeNVMe fully open-source NVMe driver stack. The RISC OS system supports a broad set of modern I/O and multimedia features: dual full-size HDMI outputs capable of up to 3840×2160 resolution, Gigabit Ethernet, and optional integrated Wi-Fi, along with two rear USB ports and provisions for two additional front-mounted USB connections via a header. Audio is delivered via HDMI, and the modular layout allows straightforward upgrades, additional cooling, or expansion without specialist tools. Complementing this, the PLUS FIVE module extends the DIY THREE by adding a secondary computing layer powered by a Compute Module 5 I/O board. This Linux companion runs at up to 2.3 GHz with 4 GB of RAM and 64 GB of eMMC storage as standard, and there are options to add extra NVMe storage or increase memory for more demanding tasks. The two systems are linked, enabling seamless sharing of files, services, and workflows between RISC OS and Linux. In everyday use, the combined system means RISC OS can remain the main interactive environment - ideal for traditional applications, development tools, and legacy workflows - while the Linux side handles modern utilities, network services, background processes, or software not natively available on RISC OS. Files can be exchanged freely between the two systems, making shared storage or cross-platform toolchains straightforward. Physically, the STACKER retains a compact footprint, with additional height, rather than a separate external unit. Its modular construction makes assembly, maintenance, and future upgrades accessible, and the entire unit presents a cohesive, integrated dual-system solution in a unified chassis. The STACKER offers a balanced and capable dual- platform workstation, combining the speed and simplicity of RISC OS with the breadth and flexibility of Linux — all in a tidy, expandable form factor that grows with your needs. STACKER comes with a suitable PSU included. Technical Specification RISC OS Linux Processor Speed: 2GHz 2.3GHz Memory: 4GB 4GB SSD Storage: 256GB NVMe Optional NVMe Networking: Gbps Ethernet Gbps Ethernet integrated WIFI Integrated WIFI USB ports: 2 rear 2 rear Audio/Video: HDMI audio HDMI audio 2x full HDMI 2x full HDMI 4K 3840x2160 4K 3840x2160 eMMC: 32GB 64GB OS and Software: RISC OS 5.30 Pi OS Trixie Case: Veneered unfinished oak slices - 140mm x 120mm x 60mm Power and activity indicator LEDs Options: 8GB RAM upgrade from 4GB NVMe Drive Pre-build Service

NVMe Drive Upgrade