DEC J-11
Encyclopedia
The J-11 is a microprocessor
chip set that implements the PDP-11
instruction set architecture (ISA) jointly developed by Digital Equipment Corporation
and Harris Semiconductor. It was a high-end chip set designed to integrate the performance and features of the PDP-11/70 onto a handful of chips. It was used in the PDP-11/73
, PDP-11/83 and Professional 380
.
It consisted of a data path chip and a control chip in ceramic leadless packages mounted on a single ceramic hybrid DIP package. The control chip incorporated a control sequencer and a microcode ROM. An optional separate floating-point acclerator (FPA) chip could be used, and was packaged in a standard DIP. The data path chip and control chip were fabricated by Harris in a CMOS process while the FPA was fabricated by Digital in their "ZMOS" NMOS process.
The design originally was intended to support multiple control chips to allow implementation of additional instructions such as the Commercial Instruction Set (CIS), but no such control chips were ever offered.
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
chip set that implements the PDP-11
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
instruction set architecture (ISA) jointly developed by Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
and Harris Semiconductor. It was a high-end chip set designed to integrate the performance and features of the PDP-11/70 onto a handful of chips. It was used in the PDP-11/73
PDP-11/73
The PDP-11/73 was the third generation of the PDP-11 series of 16-bit minicomputers produced by Digital Equipment Corporation to use LSI processors...
, PDP-11/83 and Professional 380
DEC Professional (computer)
The Professional 325 and Professional 350 were PDP-11 compatible microcomputers introduced in 1982 by Digital Equipment Corporation as high-end competitors to the IBM PC...
.
It consisted of a data path chip and a control chip in ceramic leadless packages mounted on a single ceramic hybrid DIP package. The control chip incorporated a control sequencer and a microcode ROM. An optional separate floating-point acclerator (FPA) chip could be used, and was packaged in a standard DIP. The data path chip and control chip were fabricated by Harris in a CMOS process while the FPA was fabricated by Digital in their "ZMOS" NMOS process.
The design originally was intended to support multiple control chips to allow implementation of additional instructions such as the Commercial Instruction Set (CIS), but no such control chips were ever offered.