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The BBC Microcomputer System (BBC Micro)

BBC Micro Options

Introduction

There were a wide range of upgrades and add-ons available for the BBC Micro, sites like Chris's Acorns describe many of these in great detail. On this page, I will be focusing on the options that I have added, or intend to add, to my Model B.

The BBC Micro was available in a a number of different versions :-

Acorn Model Code

Computer Details
ANA01 BBC model A
ANB01 BBC Model B
ANB02 BBC Model B with Econet interface
ANB03 BBC Model B with disc interface
ANB04 BBC Model B with Disc & Econet interfaces

Chris's Acorns has a full list of the Acorn Model Codes

Legacy Disk Drive Options

My Model B is the most basic "B", an ANB01 without any disk interface. Back in the day, Acorn offered a disk upgrade which consisted of an Intel 8271 Disk Controller, an Acorn Disc Filing System (DFS) ROM and 1 or 2 x 5.25" floppy disk drives.

The Acorn DFS is a single sided, single density 40 or 80 track format. A double sided disc can hold two DFS volumes. The DFS provided  storage for up to 31 files and 200 kilobytes of data on a single sided disc, and up to 124 files and 800 kilobytes on a fully equipped BBC Micro with two double sided disc drives.

The 8271 disk controller was quickly obsolete and Acorn introduced an updated daughter board using the Western Digital 1770 Disk Controller with a 1770 DFS ROM. Around the same time, Acorn released the Advanced Disk Filing System (ADFS) ROM which took advantage of the features of the WD1770 to utilise double density disk support.

See this page for information on the disk drives used with the BBC Micro.

 

Contemporary Disk Options

In order to upgrade my Model B to support floppy disk drives, I chose to add a disk interface from RetroClinic who advertises disk controller upgrade kits on ebay and describes its features as :-

"A new full disc interface upgrade kit for the BBC Micro Model B, which allows you to connect disc drives to your Beeb. The 1770 disc interface kit supersedes the older 8271 type and has several enhancements:

  • Supports double density, allowing the use of the ADFS filing System
  • Faster disc access
  • Built in formatting and verify commands
  • Allows the use of 3.5" disc drives as well as the original 5.25"

This kit uses the later 1772 chip, which is even faster than the 1770, and loads, formats and saves quicker. The board is compatible with the Acorn ADFS system, as well as other DFS filing systems, such as Watford Electronics DDFS 1.54T. This system is also fully compatible with discs written with the earlier 8271, so if you have an older disc collection, the new 1770 based boards will still be able to use them all quite happily.

Comes will all the additional parts and accessories needed, including Disc Filing System User Guide, fitting instructions, and the Acorn ADFS 2.26 on ROM, which also includes the SRAM commands, enhancing the use of Sideways RAM, if you have it fitted. "

 

Disk Drives

I also purchased a pair of disk drives from RetroClinic

The drives are mounted in a Akhter plinth that sits between the BBC computer and the monitor. The plinth was originally fitted with 2 x 5.25" drives, switchable between 40/80 tracks. I wanted the flexibility to use 3.5" floppies, so I had Mark replace one of the drives with a 3.5" unit.

Close up of the centre of the facia, including the drive track selection switch

 
   

DataCentre from RetroClinic

Although the floppy disk drives were a useful and almost essential upgrade for my Mode B, floppy drives and particularly the media are notoriously unreliable, especially when the media has not been well treated. In addition, with modern PCs lacking floppy drives, the transfer of software onto the BBC was somewhat problematic.

To get around these difficulties and add additional functionality to my Model B, I have also added an external DatsCentre to the system

For full details, see my DataCentre page

External DataCentre kit (ebay)

 

Other options that I have yet to document :-

 

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