PDP-9
Hardware
Hardware
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The PDP\-9, which is "two metres wide and about 75cm deep," is approximately twice the speed of the PDP\-7\. It was built using discrete transistors, and has an optional integrated [vector graphics](/wiki/Vector_graphics "Vector graphics") terminal. The PDP\-9 has a memory cycle time of 1 microsecond, and weighs about . The PDP\-9/L has a memory cycle time of 1\.5 microseconds, and weighs about .

It is DEC's first microprogrammed machine.

A typical configuration included:
* 300 cps [paper tape](/wiki/Paper_tape "Paper tape") reader
* 50 cps paper tape punch
* [DECtape](/wiki/DECtape "DECtape") for operating system and user files
* 10 cps [console teleprinter, Model 33 KSR](/wiki/Teletype_Model_33 "Teletype Model 33")
[thumb\|Model 33 Teleprinter, similar to the PDP\-9's console device, though the PDP\-9 had faster dedicated paper tape devices instead of the integrated reader/punch.](/wiki/File:Teletype-IMG_7287.jpg "Teletype-IMG 7287.jpg")

Among the improvements of the PDP\-9 over its PDP\-7 predecessor are:
* the addition of status flags for reader and punch errors, thus providing added flexibility and for error detection
* an entirely new design for multi\-level interrupts, called the Automatic Priority Interrupt (API) option
* a more advanced form of memory management

User/university\-based research projects for extending the PDP\-9 include:
* a hardware capability for [floating\-point arithmetic](/wiki/Floating-point_arithmetic "Floating-point arithmetic"), at a time when machines in this price range used software for floating\-point arithmetic
* a PDP\-9 controlled parallel computer


Can the PDP-9 be used for tasks other than computing?