systems:pdp7_unix
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systems:pdp7_unix [2015/12/29 23:53] – wkt | systems:pdp7_unix [2015/12/30 00:04] – wkt | ||
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The // | The // | ||
- | < | + | < |
- | + | link(dir, file, newname) | |
- | </file> | + | </code> |
where // | where // | ||
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So that every user did not need to maintain a link to all directories of interest, there existed a directory called // | So that every user did not need to maintain a link to all directories of interest, there existed a directory called // | ||
- | < | + | < |
+ | ln dd ken ken | ||
ln ken x x | ln ken x x | ||
rm ken | rm ken | ||
- | |||
</ | </ | ||
Line 46: | Line 46: | ||
The // | The // | ||
- | < | + | < |
+ | chdir dd ken | ||
</ | </ | ||
Line 90: | Line 90: | ||
Curiously, the primitives that became // | Curiously, the primitives that became // | ||
- | < | + | < |
+ | smes(pid, message) | ||
(pid, message) = rmes() | (pid, message) = rmes() | ||
- | |||
</ | </ | ||
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Another mismatch between the system as it had been and the new process control scheme took longer to become evident. Originally, the read/write pointer associated with each open file was stored within the process that opened the file. (This pointer indicates where in the file the next read or write will take place.) The problem with this organization became evident only when we tried to use command files. Suppose a simple command file contains | Another mismatch between the system as it had been and the new process control scheme took longer to become evident. Originally, the read/write pointer associated with each open file was stored within the process that opened the file. (This pointer indicates where in the file the next read or write will take place.) The problem with this organization became evident only when we tried to use command files. Suppose a simple command file contains | ||
- | < | + | < |
+ | ls | ||
who | who | ||
- | |||
</ | </ | ||
and it is executed as follows: | and it is executed as follows: | ||
- | < | + | < |
- | + | sh comfile> | |
- | </file> | + | </code> |
The sequence of events was | The sequence of events was | ||
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The very convenient notation for IO redirection, | The very convenient notation for IO redirection, | ||
- | < | + | < |
+ | ls>xx | ||
</ | </ | ||
to get a listing of the names of one's files in //xx//, on Multics the notation was | to get a listing of the names of one's files in //xx//, on Multics the notation was | ||
- | < | + | < |
+ | iocall attach user_output file xx | ||
list | list | ||
iocall attach user_output syn user_i/o | iocall attach user_output syn user_i/o | ||
- | + | </code> | |
- | </file> | + | |
Even though this very clumsy sequence was used often during the Multics days, and would have been utterly straightforward to integrate into the Multics shell, the idea did not occur to us or anyone else at the time. I speculate that the reason it did not was the sheer size of the Multics project: the implementors of the IO system were at Bell Labs in Murray Hill, while the shell was done at MIT. We didn't consider making changes to the shell (it was // | Even though this very clumsy sequence was used often during the Multics days, and would have been utterly straightforward to integrate into the Multics shell, the idea did not occur to us or anyone else at the time. I speculate that the reason it did not was the sheer size of the Multics project: the implementors of the IO system were at Bell Labs in Murray Hill, while the shell was done at MIT. We didn't consider making changes to the shell (it was // | ||
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The only extant source code from the PDP-7 version of Unix appears to be the source code to the // | The only extant source code from the PDP-7 version of Unix appears to be the source code to the // | ||
- | I happened to dredge up an old notebook and found a listing of the PDP-7 version of dsw. Because several people have approached me recently about reviving a version of PDP-7 Unix as a sort of paleontological exhibit, and because the subject has been discussed here, I thought people might be interested in seeing the code. I first considered net.sources, | + | I happened to dredge up an old notebook and found a listing of the PDP-7 version of dsw. Because several people have approached me recently about reviving a version of PDP-7 Unix as a sort of paleontological exhibit, and because the subject has been discussed here, I thought people might be interested in seeing the code. I first considered net.sources, |
Notes: | Notes: | ||
Line 159: | Line 159: | ||
- "sys save" makes a core image. | - "sys save" makes a core image. | ||
- | < | + | < |
+ | " dsw | ||
lac djmp | lac djmp |
systems/pdp7_unix.txt · Last modified: 2023/02/16 08:04 by admin