PDP-11 Variations Onathae
PDP-11 Variations on aThae This uniquely successful computer family is based the need for multiplexers or synchronizing hard- around a compatible set of processors -ranging ware. Memory and peripherals can send, receive, or from single-board microcomputers to full multi- exchange data without processor intervention and purpose computer systems. All of these processors without intermediate buffering in memory. Thus, are built upon a common architecture that uses a an I/O device can be communicating with memory similar instruction set and input/output system. at the same time the processor is performing This common architecture means you can expand computations. a PDP- 1 1 system when your workload grows, since Direct communication over the UNIBUS means the nearly all of our peripherals and software will work PDP-11 does not require separate I/O instructions. with any PDP- 1 1 processor. It also means you can The same instruction that performs a register-to- have a mix of PDP- 11 systems doing different register transfer within the central processor can things and they will be able to communicate among perform a memory to I/O device transfer, an I/O themselves.A single development and documenta- device to memory transfer, or a transfer between tion effort will support them all. But most of all, two I/O devices. this commonality means you can start today with the PDP-11 system you want, knowing it can grow Software Compatibility with you in any direction to meet tomorrow's needs. Since all PDP- 1 1 processors use the same basic in- A key factor in the PDP- 1 1family's success is that struction set, programs developed on one PDP- 11 all system elements -processor, memory, periph- are immediately usable on larger models and, by erals-plug into a UNIBUSm,a single, high-speed, using the proper coding conventions, on smaller data path.
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