I used punched cards and paper output (continuous fan-fold wide format) from line printers exclusively until 1972. Even after that, cards and hard copy output w

I used punched cards and paper output (continuous fan-fold wide format) from line printers exclusively until 1972. Even after that, cards and hard copy output were still used on many systems I worked with until around 1980. A number of changes had to take place before monitors could replace punched cards and paper. The early terminals were hardcopy. The Teletype 33 terminal [1] was popular and so were the IBM 2741 and Digital DECwriter. These worked fine and were better than punching cards, but they couldn't be used on many systems. I saw these mostly on minicomputers where there was only a handful of people (often just one) using the computer at a time. The most dominant mainframe operating systems from around this time (IBM 360 MFT, MVS) were not capable of handling I/O interrupts efficiently enough to support a number of users working at terminals. The hardware and operating systems of these mainframes were designed around an architecture that supported batch processing: read in a program from a deck of cards, read in the data from a large stack of cards, run the program for minutes or hours, print out the results on a line printer. A properly sized mainframe would be running jobs continuously throughout the day and most of the night, but it would be (mostly) running one job at a time. These early operating systems and the hardware I/O bus designs supported batch processing well but wouldn't have supported large numbers of concurrent programmers sitting at there own terminals connected to the system. The rise of timesharing operating systems like Multics and Unix provided additional impetus for video display terminals (VDTs), but it wasn't until around 1976 that really affordable VDTs were even available. The ADV 3 was a nice terminal that came out in 1976, see [2]. I couldn't afford one, but I knew someone that had one and was able to work from home over a 300 bit/sec acoustic modem. It had 24 lines of 80 characters (from the 80 columns that cards had). It wasn't until 1978 that the DEC vt100 was produced. In 1984, I was in software development at IBM and we were still using the 3270 terminal [3]. This terminal was connected to a mainframe timesharing system that still had trouble processing each keystroke as it was typed. Instead, the IBM 3270 was a block or page oriented terminal where you filled out the screen of text and then pressed the transmit key to send the whole screen full of text to the system in one transmission. [1] https://en.wikipedia.org/wiki/Teletype_Model_33 https://en.wikipedia.org/wiki/Teletype_Model_33 [2] https://en.wikipedia.org/wiki/ADM-3A https://en.wikipedia.org/wiki/ADM-3A [3] https://en.wikipedia.org/wiki/IBM_3270 https://en.wikipedia.org/wiki/IBM_3270