As initially introduced, the Level 6 consisted of three models: the 6/06, the 6/34, and the 6/36. The CPU featured a
real-time clock, a
ROM bootstrap loader and 64
interrupt levels. The architecture provided a variety of
addressing modes and 18 programmer-visible
registers.
Rack-mount and tabletop versions were available. These systems supported up to 64 K
words (KW) of
MOS memory with a cycle time of 650 nanoseconds. All three models all featured the
Megabus, which was a proprietary
asynchronous bus architecture. By 1978, the line had been extended downwards with the introduction of the 6/23 and 6/33, and upwards with the 6/43, 6/47, 6/53, and 6/57. The 6/23 did not support the Megabus. The 6/33 was the new entry-level upgradable model. The other four models supported up to 1 MW (Mega Words) of memory and 26 registers. A
memory management unit (MMU), optional on the 6/43 and 6/47, and standard on the 6/53 and 6/57, supported
memory segmentation and four
protection rings. An optional
Scientific Instruction Processor (SIP) added single- and double-precision hardware
floating-point instructions. The 6/47 and 6/57 were enhanced versions of the 6/43 and 6/53 respectively which added a
Commercial Instruction Processor (CIP) including 30 additional instructions for character-string manipulation and
decimal arithmetic. Among the final developments in the line were the high-end 32-bit 6/95-1, 6/98-1 and dual processor 6/95-2 and 6/98-2 models. In the 1980s, Honeywell's Datanet 8 line of communications processors, often used as front-end processors for DPS 8 mainframes, shared many hardware components with DPS 6. Another specialised derivative of the Level 6 was the
Honeywell Page Printing System. In June 1986, following Honeywell Information Systems' merger with
Bull, Honeywell Bull introduced the DPS 6 Plus line of
symmetric multiprocessing 32-bit systems, models 410 and 420 (code named MRX - Medium Range eXtended) with up to four processors. In 1987 they introduced the
uniprocessor models 210 and 220 (code named LRX - Low Range eXtended), announced the HRX (High Range eXtended), and
Computerworld reported that there were more than 50,000 DPS 6 systems installed worldwide. The HRX was introduced as the DPS 6000 600 series. Recognising the commercial success of Unix, in 1988 Honeywell Bull introduced an 80386-based Unix co-processor for the DPS 6 Plus 400 series. ==Software==