The Retro Master!

As promised in an earlier post, here’s the low down on my retro 8bit pride and joy; my BBC Master!


The BBC Master 128K, the bigger, badder brother of the BBC Micro computer – a real beast of a (8bit) machine! And this one is mine, all mine! mwahahaha….

Now, back in the day this machine’s specs were impressive indeed… it boasted 128Kb of RAM (compared to the 32Kb of the BBC Micro). Now Acorn had an interesting approach to memory. The Master didn’t have 128Kb of RAM like you’d think of it today, oh no… It still had 32Kb of ‘main’ RAM (like the Micro) however the Master also had 20Kb of dedicated video RAM, 12Kb of ‘OS workspace’ RAM and 64Kb of ‘sideways’ RAM. It’s processor was a whopping 2Mhz 6502 based chip, it also had 4 channel sound and 8 different graphics modes (including the famous ‘teletext’ mode).

All in all, far superior in many ways to the old Micro. However advanced it was, it had some problems running software and games that had been designed for the Micro due to the way that some programs had been written (using illegal opcodes or addressing hardware directly for instance). Not the end of the world, but a bit frustrating.

Here we see the innards of my BBC Master.


This machine I purchased, fully reburbised from Retroclinic as I’d decided that after the tinkering I’d had to do with the hardware to get my old Micro working I’d quite like to get a head-start with the Master. Also the one of the reason’s I went to Retroclinc was because this Master had been outfitted with a Compact Flash memory card acting as an internal Hard Drive.


A BBC Master with a Hard drive! A whopping 512Mb of storage space. Needless to say this is going to take some time to fill up!

I’ve also fitted an additional upgrade – an updated version of the Operarting System (MOS3.5 instead of MOS3.2) which provides a number of benefits (one of which is that the clock works post year 2000!). However should, for some reason, I need to switch back to MOS3.2 there’s a handy switch which will alter a circuit on the PCB that’s holding the OS chip and revert it to the MOS3.2 ROM image. Funky.


So, there we have it! It’s made of awesome, I love it!


But i’ve already decided on the next upgrade I’m getting for it… USB expansions! Oh yes. Bringing the BBC Master screaming into the modern computer world, that clever chap Mark at Retroclinic has gone and done it again and created the DataCentre! I’m going to save the pennies for that, oh yes!

Expect further retroblogging in the future!

The days of floppy disk drives

If you never had the joy of using floppy disks then you don’t know what you’ve missed out on as far as I’m concerned… and I don’t even mean the old 3.5″ disks, they weren’t floppy enough for me… I’m talking about the good old 5.25″ disks!

But anyway… in my quest of reliving by days with an Acorn BBC computer, I dug out my old collection of 5.25″ disks, tracked down a working floppy drive and was stunned to find that they all still worked! Not one had corrupted, fantastic! I don’t have that luck with CDs I’ve recorded last week!

Now, there is a tonne of BBC software on the internet, thoughtfully put there orignally for use with emulators. However, this software works just as well (if not better) on a real BBC.
But how to transfer it?

It turns out that whilst modern PCs don’t come with actual floppy disk drives, some do still come with FDCs (Floppy Disk Controllers) on the motherboard.
This I thought was a promising start.
However it seems that to save costs, manufacturers have cut corners on these FDCs so that most do not support Double Density operation, let alone the Single Density operations needed to write standard BBC DFS (Disk Filing System) compatible disks.
What I needed was an old computer with an old FDC in it.

As it so happens, I have an old Dell laptop I rescued from a bin at work several years ago – it’s totally knackered – however it has a SD compatible FDC and built in 3.5″ drive – Bingo!

So now I have a PC capable of writing to Single Density 3.5″ disks (making use of fantastic OmniFlop program) and a BBC capable of reading 5.25″ disks…


However, after some reading up I discovered that a choice upgrade my old BBC had been fitted with was an improved Disk Controller, based on the 1770 chip as opposed to the standard 8271 that Acorn used (it had, at the time been fitted to give access to Double Density as well as Single Desnity formats). The 8271 wasn’t able to work with 3.5″ drives, but 1770 based systems were! Hooray!

So I tracked down a internal 3.5″ drive, hooked it up and it worked!

5.25 and 3.5 inch drives, living in harmony

The 5.25″ drive I’d gotten my hands on had originally been part of a dual disk system, but only one of the drives still worked. With the help of a drive enclosure from eBay (where else?) I was able to snuggly slot the 3.5″ drive into the housing along with the 5.25″ drive.

Twin drives in their housing