The Honeywell series are rebranded versions of General Electric’s 600 series, which were in production from 1970 to 1989. The exclusive model was the 6080, which gave a performance of one MIPS. Other versions were the 6030, 6040, 6050, and 6060. A 6000-series computer from Honeywell with addressing alterations to enable the Multics operating system was presented as the 6180 in 1973. In 1974, Honeywell developed the 68/80, which supported a huge (2–8 million word) directly accessible memory and added cache memory to each CPU.
The Level 66 computers, which were marginally faster (to 1.2 MIPS) and provided bigger memory, replaced the 6000-series systems in 1975. The series was once more given the names 66/DPS in 1977 and DPS-8 in 1979, with a little performance boost to 1.7 MIPS in each year. The DPS-8/M was the Multics model.
The central processing unit
Addresses were 18 bits, while the CPU used 36-bit words. The Accumulator Register (AQ) had a total bit count of 72, but it could also be accessed independently as either two 36-bit registers (A and Q) or four 18-bit registers. The exponent for floating point calculations was kept in an eight-bit exponent register (the mantissa was in AQ). There were eight X0 through X7 eighteen-bit index registers.
The base address and the number of 1024-word blocks allotted to the application were stored in the 18-bit Base Address Register (BAR) (the 6180 used segmentation rather than the BAR). A 27-bit Timer Register (TR) with a precision of 2 s and an 18-bit Instruction Counter (IC) were also incorporated into the system. Debugging and fault finding were accomplished using sets of specialised registers.
A system controller in each memory module of the 6000-series computers was stated to be “memory focused,” arbitrating demands from other system components (processors, etc.). A system may handle one or two memory modules for a maximum of 256 K words, each memory module containing 128 K words of 1.2 s 36-bit words (1 MB of 9-bit bytes). Two-way interleaved memory was offered by every module.
The 6000 was compatible with several processors and IOMs. Each memory module featured eight ports for connecting to other system components, including an interrupt cell for each port, whereas each CPU and IOM had four ports for attaching to the memory. A base and bounds register in the CPU, the Base Address Register, was used for memory protection and relocation (BAR). For each I/O request, the contents of the BAR were sent to the IOM, enabling it to use virtual addresses instead of physical ones.
The General Comprehensive Operating System (GCOS), which Honeywell initially acquired from General Electric’s GECOS, served as the line’s main operating system. A revised version of GCOS 8, known as GCOS 8, was released by Honeywell in 1978 and featured virtual memory. Selected CPU models could also run the Multics OS.
In an effort to keep Xerox’s devoted clientele, Honeywell acquired Xerox Data Devices (XDS) in 1974 and created a version of the Xerox operating system CP-V called CP-6 that ran on DPS-8 systems.