page_title: PDP-4
section_title: Hardware
hierarchical_section_title: PDP-4 / Hardware
caption_attribution_description: English: The keyboard has special function red keys that control local functions such as local line feed, keyboard lock and unlock, break, repeat and local carriage return. The FIGS (figures) and LTRS (letters) keys are in the bottom row of green keys, just above the space bar.
context_page_description: The PDP-4 was the successor to the Digital Equipment Corporation's PDP-1.
context_section_description: The system's memory cycle was 8 microseconds, compared to 5 microseconds for the PDP-1.
  The PDP-4 weighed about 1,090 pounds (490 kg).
caption: The PDP-4's console typewriter was a Teletype Model 28 ASR, with a built in paper tape reader and paper tape punch.
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