ZX Desk brings overlapping GUI to 48K Spectrum

While modern desktop software routinely consumes gigabytes of RAM on web-view wrappers, ZX Desk is a masterclass in low-level engineering and empirical optimization under severe 8-bit hardware constraints.

• –Real-time frame discipline: Window dragging executes within a single 69,888 T-state 50Hz frame on authentic hardware using strict beam scheduling and interrupt synchronization.
• –Debunking platform folklore: Empirical measurements on real silicon showed that ULA memory contention adds only 14.7% overhead to screen writes rather than the widely assumed 50% penalty.
• –Counter-intuitive bottlenecks: Hardware profiling revealed that text string rendering accounts for half of window draw time, while per-row address math and register swapping vastly outweigh raw pixel fill throughput.
• –Robust systems design: Implements modular device abstraction layers, table-driven control rendering, and a memory heap designed to eliminate 16-bit address wraparound bugs.