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UNIX初期の歴史再検証 --- Part4


   http://cm.bell-labs.co/who/dmr/には多数の文献が挙げられていますが、そのうちで、まずThe Evolution of the Unix Time-sharing Systemを見て行きます。


・Unix was born in 1969 not 1974

・For computer science at Bell Laboratories, the period 1968-1969 was somewhat unsettled.

・The main reason for this was the slow, though clearly inevitable, withdrawal of the Labs from the Multics project

・Even though Multics could not then support many users, it could support us, albeit at exorbitant cost. We didn't want to lose the pleasant niche we occupied, because no similar ones were available; even the time-sharing service that would later be offered under GE's operating system did not exist.

・Besides the financial agitations that took place in 1969, there was technical work also. Thompson, R. H. Canaday, and Ritchie developed, on blackboards and scribbled notes, the basic design of a file system that was later to become the heart of Unix.

・he started work on a new operating system for the GE-645

・when it became clear that the lifetime of the 645 at the Labs was measured in months, the work was dropped.

・Also during 1969, Thompson developed the game of 'Space Travel.'
  --同時にこの時期にトンプソンはSpace Travelというゲームを作った

・It did not take long, therefore, for Thompson to find a little-used PDP-7 computer with an excellent display processor; the whole system was used as a Graphic-II terminal.

・He and I rewrote Space Travel to run on this machine.
  --トンプソンとリッチーは、PDP-7上でSpace Travelを動かした

・Space Travel, though it made a very attractive game, served mainly as an introduction to the clumsy technology of preparing programs for the PDP-7. Soon Thompson began implementing the paper file system (perhaps 'chalk file system' would be more accurate) that had been designed earlier.
  --Space Travelの作成は、PDP-7に習熟するのに役立った。まもなく、トンプソンは黒板に書いたアイデアであったファイルシステム(冗談で「チョークファイルシステム」と書かれている)を実装し始めた。

・Then came a small set of user-level utilities: the means to copy, print, delete, and edit files, and of course a simple command interpreter (shell).

・Up to this time all the programs were written using GECOS and files were transferred to the PDP-7 on paper tape

・Although it was not until well into 1970 that Brian Kernighan suggested the name 'Unix,' in a somewhat treacherous pun on 'Multics,' the operating system we know today was born.

・the file system of PDP-7 Unix was nearly identical to today's

・the system was not multi-programmed; only one program was in memory at a time

・it was clear that the PDP-7, a machine we didn't even own, was already obsolete

・In early 1970 we proposed acquisition of a PDP-11, which had just been introduced by Digital.

・the amount of money (about $65,000)

・the charter sought was not merely to write some (unspecified) operating system, but instead to create a system specifically designed for editing and formatting text, what might today be called a 'word-processing system.'

・an order for a PDP-11 was placed in May

・The processor arrived at the end of the summer, but the PDP-11 was so new a product that no disk was available until December.

・In the meantime, a rudimentary, core-only version of Unix was written using a cross-assembler on the PDP-7.

・the first version of Unix for the PDP-11 represented a relatively minor advance over the PDP-7 system

・there was no multi-programming; only one user program was present in core at any moment

・the most interesting thing about the enterprise was its small size: there were 24K bytes of core memory (16K for the system, 8K for user programs)

・The experiment was trying but successful. Not only did the Patent department adopt Unix, and thus become the first of many groups at the Laboratories to ratify our work, but we achieved sufficient credibility to convince our own management to acquire one of the first PDP 11/45 systems made.

・Every program for the original PDP-7 Unix system was written in assembly language

・Thompson decided that we could not pretend to offer a real computing service without Fortran

・As I recall, the intent to handle Fortran lasted about a week. What he produced instead was a definition of and a compiler for the new language B

・a version of the multi-precision `desk calculator' program dc was one of the earliest programs to run on the PDP-11

・Only passing thought was given to rewriting the operating system in B rather than assembler, and the same was true of most of the utilities.

・This approach was taken mainly because of the slowness of the interpretive code.

・in 1971, work began on what was to become the C language

・the most important watershed occurred during 1973, when the operating system kernel was rewritten in C.

・the most far-reaching change was the introduction of multi-programming


・first Editionのマニュアルに書かれているUNIXはPDP-11上で動いた。
・first Editionの表紙に書かれている日付は1971年11月であるが、その前の1969年にPDP-7向けにUNIXが作られていた。
・その時にPDP-7上でゲームSpace Travelを作った経験が生きた。ただし、Space TravelとUNIXとが直接関係しているとは書かれていない。


・バージョン1が作られた時点ではPDP-11は初期版の1機種しかないことが、Gordon Bell他著の"Computer Engineering"の表からわかり、これはPDP-11/20と呼ばれるものであるから、バージョン1の対応機種はPDP-11/20である。
・Space TravelというゲームとUNIXの関係だが、"Space Travel, though it made a very attractive game, served mainly as an introduction to the clumsy technology of preparing programs for the PDP-7"という表現から見て、ゲームを作ることでPDP-7に慣れたというだけのことで、直接の関係はないだろう。たとえば、ゲームのスコアを記録するためにファイルシステムを作ったというようなことではなさそうである。


バージョン日付 台数 ハード メモリ
バージョン0 1969 1 PDP-7  
バージョン1 1971/11 10 PDP-11/20 24KB
バージョン2 1972/6 6 PDP-11/20  
バージョン3 1973/2 4    
バージョン4 1973/11 30    
バージョン5 1974/6      
バージョン6 1975/5   PDP-11/40  
バージョン7 1979/1   PDP-11/45,70  

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