Not much in the way of dazzling utilities this EUG because of the hours and hours of exams I've got. However, I do have a few points:
- Why does the label of each EUG disk tell me to turn the MRB off? What is an MRB and why don't I want it? I know that in PC World, MBR is the Master Boot Record, but I've never seen an MRB!
- I subscribe to Maplin Electronics magazine, as plugged by EUG's Editor last issue (Actually, I got EUG's address from the Maplin publication!). Does anyone have issues #1 to #18 of Maplin Electronics for sale? (I'll match the cover price and P&P)
Next issue I'll have had some time to spend on the stuff I'm forever promising, but I have had time to take the Operating System chip out of the BBC I'm using and dump it to disk. (Is there a paradox there?)
It was sparked off by the fact that on the BBC and Electron, pages &FE00, &FD00 and &FC00 are memory mapped peripherals. Yet some simple maths tells you that &FFFF-&C000 is 16K, which is the length of the OS ROM. But the place that is cut out for the memory mapped peripherals must still physically exist within the OS ROM - but what is in there?
I had, of course, to unplug the OS, as these 256*3 bytes are not available, at least to the processor.
Here's what it says:
"(C) 1981 Acorn Computers Ltd. Thanks are due to the following contributors to the development of the BBC Computer (among others too numerous to mention):- David Allen, Bob Austin, Ram Banerjee, Paul Bond, Allen Boothroyd, Cambridge, Cleartone, John Coll, John Cox, Andy Cripps, Chris Curry, 6502 designers, Jeremy Dion, Tim Dobson, Joe Dunn, Paul Farrell, Ferranti, Steve Furber, Jon Gibbons, Andrew Gordon, Lawrence Hardwick, Dylan Harris, Hermann Hauser, Hitachi, Andy Hopper, ICL, Martin Jackson, Brian Jones, Chris Jordan, David Kind, David Kitson, Paul Kriwaczek, Computer Laboratory, Peter Miller, Arthur Norman, Glyn Phillips, Mike Prees, John Radcliffe, Wilberforce Road, Peter Robinson, Richard Russell, Kim Spence-Jones, Graham Tebby, Jon Thackray, Chris Turner, Adrian Warner, Roger Wilson, Alan Wright.MY
I assume that there is a similar list hidden behind the Electron OS - but this is soldered into the case so you'll never know. My next challenge is to have a probe behind the Master 128's.
Until next time, get your submissions flowing in to Gus!
Robert Sprowson
EUG is read by owners of Masters, Beebs and Electrons. Many Electrons have a Master RAM Board (MRB) fitted, which increases speed and gives 25342 (&62FE) bytes of free RAM in any Mode. But some programs that access the screen directly don't work properly with the MRB turned on. Occasionally one of these programs comes to EUG and so Elk owners are asked to switch the MRB off. If, after looking at a program, an Elk owner with MRB wants to try it with the MRB on, they can. Initally though, they should turn it off just in case it causes problems.
EUG is happy to plug the Maplin magazine first because it is good and secondly because they plug us.
Best of luck finding the back issues of the Maplin magazine!
Gus Donnachaidh, EUG #26