design. The BBC eventually chose a computer from Acorn Computers Ltd. As a result of the BBC's decision, the British Technology Group, which had replaced the NEB, sold the final design and production to Grundy. Grundy had been looking for an entrant into the personal computer business, as they were already producing a CP/M 2.2-based machine, built into a 'dumb terminal' as a virtual clone of the Intertec Superbrain. Models Two main models were released. The model 'A' needed to display on either a TV or a monitor. The model 'AD' also included a one-line, 16-character, vacuum fluorescent (VF) display on the unit which permitted operation with or without a TV screen or monitor — the VF display responded to the cursor keys and scrolled around the screen display area. One additional model was released, but this was a custom version for a pharmaceutical chain, with no screen display — only the VF display — and was not widely known. An expansion chassis was released, providing an additional 64 kB of paged memory. Since the Z80 has a 16-bit address bus, it can only address 64 kB of memory at a time. The paged memory system in the expansion chassis used bank switching to allow the NewBrain to take advantage of several 64 kB modules. The expansion module included a parallel printer port and two hardware based serial ports and an expansion bus to connect further modules such as the 8 and 16 way serial modules under development. The expansion module included Series 2 software, replacing those in the processor module as well as software for the new devices. CP/M 2.2 was also available. Under CP/M 2.2 the internal BASIC ROM was paged out for the CP/M ROM but this gave only 32 kB memory to CP/M. With the expansion module fitted the three 8 kB ROMs of the processor module were paged out to give the NewBrain one of the highest available TPA (Transient Program Area — memory left after the OS demands are satisfied) to CP/M. Grundy Business Systems released two 5.25" drive formats, 40 track 200 kB single sided and 80 track 800 kB double sided. Several independent dealers provided 40 track 400 kB double sided drive. In 1983 the Sony 3.5" became available and single and paired units were supplied to dealers in the NewBrain cream cases. The 3.5" 800 kB discs also got a more