On 07/16/2017 02:50 PM, Paul Berger via cctalk wrote: > That print technology was pretty common everywhere but at IBM for > high speed line printers. When I was in college the service bureau > that processed our FORTRAN had one that if I remember correctly was > made by Honeywell and featured wavy print lines. The operators told > us that printing graphic was very hard on this printer because if you > printed a whole line of the same character every hammer fired at > once, it made an awful racket and visibly shook the printer.
Yup. The CDC 501 drum printers had a switch for "high" versus "low" speed. Basically, it was a "do you want fast or readable"? IIRC, 500 LPM slow, vs. 1000 LPM fast. A little gunk in the pivot of a print hammer could render that column unreadable. Basically a machine-gun sound. The 501s that we used printed a lot of core dumps. The result was that the "0" characters wore out more quickly than others. That is, the '0' characters stared looking blurry. I recall having to go through a bunch of Univac 1108 engineering manuals printed on a very wavy drum printer. A bottle of aspirin was helpful. Train/chain printers, o the other hand, had duplicates of the more commonly printed characters, so not as bad--and the print slugs could be individually replaced if they got too bad. There, the waviness was lateral and not nearly as hard on the eyes and the vertical displacement of the drum units. --Chuck
