BBC Model B+128K

The BBC Model B +128K was the final model, it squeezed every last bit of memory out of an 8-bit computer. It was launched in 1984 shortly after the BBC Model B+64K and was soon replaced by the BBC Master.

Additional specifications

ROM48KB (maximum 192K ROM)
Disc ControllerWD1770PH
Disc Filing System   DFS 2.23
BBC B +128K

Inside the B +128K.
The extra 128K RAM
on the right edge.

motherboard BBC
+ 128K right edge



The "Tube" was an expansion port which was designed to connect other processors to the BBC (6502, Z80, 68000 or ARM 1 RISC). Interface cards were specially designed for the tube. For instance another 6502 with 64K of RAM or a Z80 cpu also with 64K of RAM and CP/M 2.2 as operating system. Acorn used the name CPN for CP/M obviously for a trademark reason.

Acorn Z80 Card

Since the BBC B a disc filing system was available.
On the left the back side from that unit. The small orange cable provided the power and the grey ribbon cable was connected to the FDC port from (under) the BBC case.

Acorn 6502 Card

The second processors came in a case as shown here at the right.
The most right picture shows the inside from the box.

Acorn_Z802ndprocCth.jpg Acorn_65022ndprocEth.jpg
Acorn Z80 2nd processor

The Torch Z80 Disc Pack consist of 2 parts, the Disc Pack as seen below, and the Z80 second processor. When the Torch Z80 Disc Pack was launched CP/M was widely in business and there was a wealth of software available (e.g Ashton Tate Dbase2, MicroPro Wordstar & CalcStar, Microsoft MBasic, Micro Focus COBOL). The Torch Z80 Disc Pack was one of the first second processor for the BBC Micro and gave BBC Micro users access to all the CP/M commercial and Public Domain software

Torch Z80 Card
Torch Z80 Disc Pack
Torch_Disc Pack inside
How it's build together

In the Netherlands circulated a Torch pack in a somewhat higher case that included the Z80 card and was connected to the BBC with a cable to the Tube.

A lot of RAM/ROM extension-cards were launched. See some examples below.

Watford ROM extension

Solidisk sideways 128K

WE RAM/ROM-board

A Lot of extension boards were issued. Watford and Solidisk were the most famous in that field. Nevertheless a lot of boards from unknown factories were spotted in the early 80ties from the last century. In the Netherlands at least three different types were available.