Re: [TUHS] Happy birthday, Dennis Ritchie!

Part of that problem was probably electronic, not software.   Many of the early terminals were half-duplex.  The normal mode was that the terminal typed what came over the line, and the keyboard was locked.  If you wanted to let the terminal send data, you needed to send a control character to unlock the keyboard, and then another one to lock it when you wanted to send data again. As you may know, the first PDP-11 at Bell Labs was financed by the patent department because there were very draconian rules about submitting patents (every page had to have exactly 50 numbered lines, lines could not be blank, numbers must be in order, etc.)   A change on page 3 of a 25-page patent application could mean that the whole thing had to be retyped (yes, manually...).   That need drove a lot of the early nroff work.  And, when upper/lower case terminals became common, many still had half duplex interfaces.    When the Unix software got good enough, it started to get used by real typists, who were used to electric typewriters.  There was bitter complaint about the half duplex (keyboard lock) mode -- the typists were so fast that when the keyboard locked they could break their fingernails!  Full duplex pretty much solved that problem, and Unix, as far as I remember, embraced it earlier than most other systems. Steve PS:  The Usenix publication ";login:" got its name because that's what a half-duplex system wrote for the login message when viewed on a full duplex terminal.  The ; and : were actually control characters... ----- Original Message ----- From: "Lawrence Stewart" <stewart(a)serissa.com> To:"William Cheswick" <ches(a)cheswick.com> Cc:"TUHS main list" <tuhs(a)minnie.tuhs.org> Sent:Sat, 9 Sep 2017 16:33:54 -0400 Subject:Re: [TUHS] Happy birthday, Dennis Ritchie! What, you didn’t like IBM 2741 terminals that mechanically locked the keyboard? On 2017, Sep 9, at 9:04 AM, William Cheswick <ches(a)cheswick.com [1]> wrote: Amen.  There were a number of things that really sucked at the time.   My least favorite: time sharing systems that didn’t allow type-ahead. Kids these days... On 9Sep 2017, at 12:34 AM, Steve Johnson <scj(a)yaccman.com [2]> wrote: For people used to that world, "echo hello >hi" was literally jaw dropping.  Many people had to have it explained twice, because they literally could not conceive of a file being created so easily.  I had worked in the computing center for a couple of years, and probably gave more than my share of demos to mainframe users... Steve Links: ------ [1] mailto:ches@cheswick.com [2] mailto:scj@yaccman.com