Editing IBM 1627 (section)

{{Short description|1960s era plotter made by Calcomp}}
[[File:IBM 1620 data processing machine on display, Seattle World's Fair, 1962.jpg|thumb|[[IBM 1620]] data processing machine with IBM 1627 plotter, on display at the Seattle World's Fair, 1962]]
[[File:IBM 1627 plotter.mw.jpg|thumb|IBM 1627 drum plotter. Note pen assembly is missing.]]
[[File:IBM 1627 plotter detail.mw.jpg|thumb|upright|Closeup of IBM 1627 drum plotter right side, showing controls for manually moving the drum.]]
[[File:Calcomp 565 drum plotter.jpg|thumb|A Calcomp 565 drum plotter, essentially the same as the 1627, with pen assembly.]]
The '''IBM 1627''' was a [[Rebranding|rebranded]] [[Calcomp plotter]] sold by [[IBM]] for use with the [[IBM 1620]], and, later, the [[IBM 1130]] computers. It became perhaps the first non-IBM peripheral that IBM allowed to be attached to one of its computers.

The plotter fed a roll of paper with perforated edges over a drum with matching sprockets at the sides. The drum could move the paper forward and backward (the X-axis). A pen holder slid horizontally over the paper (the Y-axis). Both the drum and the pen holder were controlled by [[stepper motor]]s. Commands included lowering the pen down to write and raising it up, and moving the drum or the pen holder one step of {{convert|1/100|in|mm}} in either direction. There were also commands to move the drum and pen together one step in the four diagonal directions.

The standard size 1627 Model 1 was a Calcomp model 565 plotter and used 12-inch-wide paper (305&nbsp;mm) with a plotting area of {{convert|11|in|mm}}. Model 1 could operate at 18,000 steps per minute. Model 2 was a Calcomp 563 and used 31-inch-wide paper (787&nbsp;mm) with a plotting area of {{convert|29+1/2|in|mm}}. Model 2 could operate at 12,000 steps per minute. 

The paper rolls were {{convert|120|ft|m}} long. A metal bar above the take-up reel allowed a finished plot to be torn off and removed. The drum would then be advanced using the manual controls and the fresh paper end taped to the take-up reel. The standard pen was a [[ball-point pen|ball-point]], but liquid ink pens were available, and typically used for higher quality plots intended for publication. Other paper stock could be taped to the drum if desired. A chart drive switch was provided to turn off the motorized paper supply and take-up reels for this purpose.