display. By using the palette to mask the top area of the display and taking care about when it changes mode it can shift the continuous graphics at the bottom of the display down in two pixel increments because the internal display counter is not incremented on blank scanlines during non-continuous graphics modes. Exile: sampled speech Exile turns the Electron's one channel output into a digital speaker for PCM output. The speaker can be programmatically switched on or off at any time but is permanently attached to a hardware counter so is normally only able to output a square wave. But if set to a frequency outside the human audible range then the ear can't perceive the square wave, only the difference between the speaker being switched on and off. This gives the effect of a simple toggle speaker similar to that seen in the 48 KB Sinclair ZX Spectrum. Exile uses this to output 1-bit audio samples. Frak! and Zalaga: Polyphonic music As part of their copy protection, illegal copies of Aardvark Software's Frak! and Zalaga would cause a pseudo-polyphonic rendition of Trumpet Hornpipe, the Captain Pugwash theme tune, to play endlessly rather than loading the game properly (Pugwash being a pirate). On the Electron version of Frak!, the tune was the main theme from "Benny Hill" (Boots Randolph's "Yakety Sax"). The polyphony was achieved via fast note-switching to achieve the necessary chords. Software A range of titles were made available on cassette at the launch of the Electron through the Acornsoft publishing arm of Acorn, including a number of games, the Forth and Lisp languages, and a handful of other educational and productivity titles. Acorn's decision to provide the Electron with a degree of compatibility with the BBC Micro meant that a number of titles already available for the older machine could be expected to run on its new machine, with only minor cosmetic issues occurring when running some titles. Of the Acornsoft languages, the existing Forth and Lisp language releases worked on the Electron (these being re-released specially for the machine), together with BCPL and Microtext (which remained BBC-only releases). Games such as Chess and Snooker, plus a number of other titles were also established as being compatible prior to launch. Various applications in Acornsoft's View suite, together with the languages Comal, Logo and ISO Pascal, were reported as being compatible with the Electron, as were some