Basic is a language ROM, factory-fitted, leaving 3 on-board sockets free. The next 16k is for application and language ROMs (and sometimes RAMs.) They interact with an API to register their capabilities, respond to OS requests, claim and free resources. There's a 1k screen mode which the machine boots into. Screen RAM is a variable amount at the high end. 32k RAM at bottom of memory shared between OS and application. 16k Basic with commands for graphics and sound, inbuilt assembler, 5 byte floats, fast integer variables, file i/o support, some support for structured programming. Graphics in teletext mode or bitmapped, from 1k to 20k memory footprint, up to 8 colours and flashing colours. 2MHz 6502 CPU, builtin keyboard, video to TV or monitor, speaker, cassette interface. Of course it boots into Basic by default, so you don't have to know much to get started.

This is a thread for helping the curious and interested to get to grips with the machine. There's an active retrocomputing scene, with several emulators and with new hardware and new software being produced. They have a lot of I/O and expansion capability and a relatively sophisticated OS with an official API. Acorn's series of BBC Micro were pretty popular in the UK, and had some presence elsewhere too.

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