Peripherals
One of the G-15's primary output devices was the typewriter with an output speed of about 10 characters per second for numbers (and lower-case hexadecimal characters u-z) and about three characters per second for alphabetical characters. The machine's limited storage precluded much output of anything but numbers; occasionally, paper forms with pre-printed fields or labels were inserted into the typewriter. A faster typewriter unit was also available.
The high-speed photoelectric paper tape reader (250 hexadecimal digits per second on five-channel paper tape for the PR-1; 400 characters from 5-8 channel tape for the PR-2) read programs (and occasionally saved data) from tapes that were often mounted in cartridges for easy loading and unloading. Not unlike magnetic tape, the paper tape data were blocked into runs of 108 words or less since that was the maximum read size. A cartridge could contain many multiple blocks, up to 2500 words (~10 kilobytes).
While the G-15 had an optional high-speed paper tape punch (the PTP-1 at 60 digits per second) for output, the standard punch operated at 17 hex characters per second (510 bytes per minute).
Optionally, the AN-1 "Universal Code Accessory" included the "35-4" Friden Flexowriter and HSR-8 paper tape reader and HSP-8 paper tape punch. The mechanical reader and punch could process paper tapes up to eight channels wide at 110 characters per second.
The CA-1 "Punched Card Coupler" could connect one or two IBM 026 card punches (which were more often used as manual devices) to read cards at 17 columns per second (ca. 12 full cards per minute) or punch cards at 11 columns per second (ca. eight full cards per minute). Partially full cards were processed more quickly with an 80 column per second skip speed). The more expensive CA-2 Punched Card Coupler read and punched cards at a 100 card per minute rate.
The PA-3 pen plotter ran at one inch per second with 200 increments per inch on a paper roll one foot wide by 100 feet long. The optional retractable penholder eliminated "retrace lines".
The MTA-2 could interface up to four drives for half-inch Mylar magnetic tapes, which could store as many as 300,000 words (in blocks no longer than 108 words). The read/write rate was 430 hexadecimal digits per second; the bidirectional search speed was 2500 characters per second.
The DA-1 differential analyzer facilitated solution of differential equations. It contained 108 integrators and 108 constant multipliers, sporting 34 updates per second.
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