Differences

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--- systems:2nd_edition [2015/12/29 16:59] – created admin
+++ systems:2nd_edition [2015/12/29 17:00] – admin
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 **Source Code: ** some source code is in the [[http://www.tuhs.org/Archive/PDP-11/Distributions/research/1972_stuff/|Unix Archive]], browsable in the [[http://minnie.tuhs.org/cgi-bin/utree.pl?file=V2|Unix Tree]]\\
 **Documentation: ** [[http://www.tuhs.org/Archive/PDP-11/Distributions/research/1972_stuff/unix_2nd_edition_manual.pdf|2nd Edition man pages]]
+The second edition of Unix was developed for the PDP-11 at Bell Labs by Ken Thompson, Dennis Ritchie and others. It extended the First Edition with more system calls and more commands. This edition also saw the beginning of the C language, which was used to write some of the commands.
+The code in the Unix Archive is only the source to some of the commands, some of the library functions, and the C compiler. The files in c/ come from the [[http://minnie.tuhs.org/Archive/Applications/Early_C_Compilers/last1120c.tar.gz|last1120c.tar.gz]] tape, and form a working C compiler for Second Edition Unix.
+The files in lib/ come from the libc.sa file which is on the last1120c.tar.gz tape, and form the C library for the compiler.
+The files in cmd/ are recreated from the text fragments found on the file [[http://minnie.tuhs.org/Archive/PDP-11/Distributions/research/1972_stuff/s1-bits.gz|s1-bits.gz]]. These were reconstructed by Doug Merritt and Warren Toomey, and form the source code to some of the commands in Second Edition Unix.
+For more information about Second Edition Unix, see [[http://cm.bell-labs.com/cm/cs/who/dmr/hist.html|The Evolution of the Unix Time-sharing System]] by Dennis Ritchie.