bbc micro - What BBC Microcomputer features were requested specifically by BBC engineers?

When requirements for the BBC Microcomputer were developed as part of the BBC Computer Literacy Project, an outline specification was created by an independent consultant, the late John Coll. This specification was then fleshed out by the BBC and given to manufacturers who were interested in tendering for the project. Acorn Computers subsequently won the contract with their innovative design, and the rest, as they say, is history.Now, whilst many of the machine's features were specified either by Acorn (for their own needs) or by the BBC (as re...Read more

Why is the BBC Micro's Mode 7 so different to the other display Modes?

Mode 7 on the BBC Micro is very different to the other seven display Modes (0-6).From the programmer's point of view, the BBC Micro's mode 7 looks like 'oh, there is also a character cell mode that saves memory', but from the BBC's viewpoint it was also about supporting the existing Teletext standard. From the hardware engineer's viewpoint it may also have been about using the existing, proven and mass-produced SAA 5050 chip, which not only provided a high-quality character display, but also a hardware implementation of Teletext features.It pre...Read more

bbc micro - Screen "garbage" in Acorn Electron games

A common feature of later games released for the Acorn Electron was the use of screen memory to store game code. This was commonly known as screen "garbage",and can be seen on games like Exile. I don't remember seeing the same effect employed on any BBC Micro games though. There's no screen garbage visible on the BBC Micro version of Exile for instance.Both the Elk and the Beeb suffered from the same memory constraints, so why was screen garbage only a feature of games for the Electron? Was there a way of masking the use of screen memory for ...Read more

bbc micro - BBC model B, 20 pinouts port on keyboard below speaker used for what?

Wondering what the 20 pinout holes was used for. It is below the speaker on the keyboard, has a further four pinouts above, and has something to do with the cartridge system in later models, I guess.Are there any mods available?Have found this item, but it doesn't fit into the pins as such, and instead connects into a rom slot via cable connector.And this also does a similar job for a sma...Read more

arm - Did any early RISC OS precursor run on the BBC Micro?

Acorn famously developed the ARM microprocessor using their existing BBC Micros internally, both to simulate the ARM and to develop for actual ARM using a Tube-connected second processor.Later, Acorn would ship the ARM-based Archimedes platform, which started the commercial life of RISC OS.I can't find any history on what Acorn used as the development environment for early versions of RISC OS, but a BBC Micro with an ARM second processor seems possible. Was any early form of an ARM-specific OS ever made public for this hardware setup?...Read more

bbc micro - Can the BBC Master 128 work fine with no battery?

The BBC Master 128 has a CMOS NVRAM and battery system for storing configuration information. I assume that a dead or removed battery just leads to the NVRAM reverting to defaults or other non-harmful state.Short of replacing the battery, can the BBC Master still be used to its full extent? How would one use it, and what MOS commands are needed?...Read more

bbc micro - BBC Basic: Inserting a control character without occupying space in Mode 7

I'm using mode 7 ("Teletext mode") on my Beeb. I'd like to print a string of unbroken characters with an coloured text control character in the middle, as-per this mock-up:However, I can't work how this can be done. The control character needs to occupy space in the output:PRINT CHR$129;"STACK"CHR$132;"OVERFLOW"I read up on held graphics mode, but this only seems to allow me to repeat the last used graphics symbol, instead of inserting a space when I print a control character. When I do try this with text I just get an additional space for the ...Read more