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Found this in Ritchie's article, "The Development of the C
Language":<br>
<blockquote>Thompson was faced with a hardware environment cramped
and spartan even for the time: the DEC PDP-7 on which he started
in 1968 was a machine with 8K 18-bit words of memory and no
software useful to him. While wanting to use a higher-level
language, he wrote the original Unix system in PDP-7 assembler. At
the start, he did not even program on the PDP-7 itself, but
instead used a set of macros for the GEMAP assembler on a GE-635
machine. A postprocessor generated a paper tape readable by the
PDP-7.<br>
<br>
These tapes were carried from the GE machine to the PDP-7 for
testing until a primitive Unix kernel, an editor, an assembler, a
simple shell (command interpreter), and a few utilities (like the
Unix rm, cat, cp commands) were completed. After this point, the
operating system was self-supporting: programs could be written
and tested without resort to paper tape, and development continued
on the PDP-7 itself.<br>
<br>
Thompson's PDP-7 assembler outdid even DEC's in simplicity; it
evaluated expressions and emitted the corresponding bits. There
were no libraries, no loader or link editor: the entire source of
a program was presented to the assembler, and the output file—with
a fixed name—that emerged was directly executable. (This name,
a.out, explains a bit of Unix etymology; it is the output of the
assembler. Even after the system gained a linker and a means of
specifying another name explicitly, it was retained as the default
executable result of a compilation.) <br>
<br>
</blockquote>
So, they didn't use DEC's assembler, but they used GE's?<br>
<br>
Interesting stuff.<br>
<br>
Will<br>
<div class="moz-cite-prefix">On 2/26/16 6:26 PM, Clem Cole wrote:<br>
</div>
<blockquote
cite="mid:CAC20D2Ns-xeP-kchmRk=M2LmHFDZ91dCqskSo-Z9HKQ3-G8nOA@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">If you were
used to building your own tools, you might not. Also if you
are bootstrapping from something else (like a large
timesharing system from another manufacturer). You might put
your tools on the other system, until the new system could
"self host."</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">We do the same
things today.</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">Clem</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Feb 26, 2016 at 7:23 PM, Will
Senn <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:will.senn@gmail.com" target="_blank">will.senn@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
<br>
Sent from my iPhone<br>
<div>
<div class="h5"><br>
> On Feb 26, 2016, at 5:28 PM, Nigel Williams <<a
moz-do-not-send="true"
href="mailto:nw@retrocomputingtasmania.com"><a class="moz-txt-link-abbreviated" href="mailto:nw@retrocomputingtasmania.com">nw@retrocomputingtasmania.com</a></a>>
wrote:<br>
><br>
>> On Sat, Feb 27, 2016 at 10:24 AM, Johnny
Billquist <<a moz-do-not-send="true"
href="mailto:bqt@softjar.se">bqt@softjar.se</a>>
wrote:<br>
>> On 2016-02-26 23:47, Eric Smith wrote:<br>
>>>> On Feb 25, 2016, at 9:26 PM, Gregg
Levine <<a moz-do-not-send="true"
href="mailto:gregg.drwho8@gmail.com">gregg.drwho8@gmail.com</a><br>
>>>> <mailto:<a moz-do-not-send="true"
href="mailto:gregg.drwho8@gmail.com">gregg.drwho8@gmail.com</a>>>
wrote:<br>
>>>><br>
>>>> Version Zero was hand coded on a PDP-7<br>
>>><br>
>>><br>
>>> I know Gregg is right. But .. Can you
/imagine?/<br>
>> Not sure I understand this comment either. Are
you suggesting that coding an<br>
>> OS is assembler is something exceptional or
complicated, or unusual?<br>
><br>
> I took "hand-coded" to mean Version Zero was
(initially) done without<br>
> an assembler, they wrote down the instructions in
machine code.<br>
><br>
> Perhaps not unusual for the 1960s but laborious
none-the-less.<br>
> _______________________________________________<br>
> Simh mailing list<br>
> <a moz-do-not-send="true"
href="mailto:Simh@trailing-edge.com">Simh@trailing-edge.com</a><br>
> <a moz-do-not-send="true"
href="http://mailman.trailing-edge.com/mailman/listinfo/simh"
rel="noreferrer" target="_blank">http://mailman.trailing-edge.com/mailman/listinfo/simh</a><br>
<br>
</div>
</div>
I don't understand this. The PDP 7 had an assembler and
debugger. Wouldn't they have used the assembler to generate
the bootstrap system?<br>
<div class="HOEnZb">
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</div>
</blockquote>
</div>
<br>
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</blockquote>
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