National Semiconductor's INS8060, or SC/MP (pronounced scamp) for Simple Cost-effective Micro Processor, is an early microprocessor which became available in April 1976. A unique feature of the SC/MP is a daisy-chained control pin that allowed up to three SC/MP's share a single main memory to produce a multiprocessor system.
To lower cost, the system used a bit-serial arithmetic logic unit (ALU) and was thus significantly slower than contemporary designs which had parallel ALUs like the Intel 8080 or MOS 6502. Another oddity was that the program counter could only access the lower 12-bits of the 16-bit address, and the upper 4-bits had to be set using special instructions. The result was that instructions accessed main memory as sixteen 4 kB "pages".[a] The combination of slow speed and paged memory limited its attractiveness, especially in the markets that might need a multiprocessing system.
I worked in an environment that had one of these. The host system was a Pentium Pro server that booted Windows NT and hosted a Series A instance using this chip.
https://en.wikipedia.org/wiki/National_Semiconductor_SC/MP
National Semiconductor's INS8060, or SC/MP (pronounced scamp) for Simple Cost-effective Micro Processor, is an early microprocessor which became available in April 1976. A unique feature of the SC/MP is a daisy-chained control pin that allowed up to three SC/MP's share a single main memory to produce a multiprocessor system.
To lower cost, the system used a bit-serial arithmetic logic unit (ALU) and was thus significantly slower than contemporary designs which had parallel ALUs like the Intel 8080 or MOS 6502. Another oddity was that the program counter could only access the lower 12-bits of the 16-bit address, and the upper 4-bits had to be set using special instructions. The result was that instructions accessed main memory as sixteen 4 kB "pages".[a] The combination of slow speed and paged memory limited its attractiveness, especially in the markets that might need a multiprocessing system.