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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. " |
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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. |
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| Close up of the centre of the facia, including
the drive track selection switch |
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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
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External DataCentre
kit (ebay) |
Other options that I have yet to document :-
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