5 Sep
2002
5 Sep
'02
10:06 a.m.
Is there a description anywhere of how C was originally bootstrapped?
I'm sure it was nothing unconventional, but the question of how you
bring up compilers for other languages which are implemented in their
own language seems to mystify some people to the extent that they
argue that the compiler must be written in C (which is `always
there'), and I thought it would be good to have the real story about C
to tell them.
Thanks
--tim
5 Sep
5 Sep
10:16 a.m.
In article by Tim Bradshaw:
Is there a description anywhere of how C was
originally bootstrapped?
Have a look at "The Development of the C Language"
at http://cm.bell-labs.com/cm/cs/who/dmr/chist.html
Warren
11:38 a.m.
On Thu, 5 Sep 2002, Tim Bradshaw wrote:
Is there a description anywhere of how C was
originally bootstrapped?
I'm sure it was nothing unconventional, but the question of how you
bring up compilers for other languages which are implemented in their
own language seems to mystify some people to the extent that they
argue that the compiler must be written in C (which is `always
there'), and I thought it would be good to have the real story about C
to tell them.
Well, I have a C compiler written in MACRO-11...
C wasn't written in C at the start, you know...
Johnny
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
11:41 a.m.
* Johnny Billquist wrote:
Well, I have a C compiler written in MACRO-11...
C wasn't written in C at the start, you know...
Yes, I realise that! Many people (not readers of this list!) seem to
assume that C is eternal though. From the paper that Warren pointed
me at (thanks) it looks like the only missing link is how TMG
originally got onto the PDP-7...
--tim
12:07 p.m.
On Thu, 5 Sep 2002, Tim Bradshaw wrote:
* Johnny Billquist wrote:
How? It was written, of course. In assembler. By that time, you already
had the assembler, an editor, and other commonly used system programs, so
it's just a case of the normal development cycle.
Johnny
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
Well, I have a C compiler written in MACRO-11...
C wasn't written in C at the start, you know...
Yes, I realise that! Many people (not readers of this list!) seem to
assume that C is eternal though. From the paper that Warren pointed
me at (thanks) it looks like the only missing link is how TMG
originally got onto the PDP-7... 
12:15 p.m.
Johnny Billquist <bqt(a)update.uu.se> writes:
On Thu, 5 Sep 2002, Tim Bradshaw wrote:
And tracing further backwards, the assembler was pheraps originally
developed in GECOS?
--
Lars Brinkhoff http://lars.nocrew.org/ Linux, GCC, PDP-10,
Brinkhoff Consulting http://www.brinkhoff.se/ HTTP programming
* Johnny Billquist wrote:
How? It was written, of course. In assembler. By
that time, you already
had the assembler, an editor, and other commonly used system programs, so
it's just a case of the normal development cycle. Well, I have a C compiler written in MACRO-11...
C wasn't written in C at the start, you know...
Yes, I realise that! Many
people (not readers of this list!) seem to
assume that C is eternal though. From the paper that Warren pointed
me at (thanks) it looks like the only missing link is how TMG
originally got onto the PDP-7... 
1:19 p.m.
* Johnny Billquist wrote:
How? It was written, of course. In assembler. By that
time, you already
had the assembler, an editor, and other commonly used system programs, so
it's just a case of the normal development cycle.
Is this known or is it deduction?
(In case there is any confusion here: I do understand very well how
compilers can be implemented on naked machines without preexisting
tools (and indeed I've done more-or-less this with assemblers on
microcomputers, ending up with a perfectly fine assembler which used
the wrong opcode names, because we didn't know what the right ones
were...). So my question `how was x done' is not `I don't understand
how you can do this' but `historically, what were the steps in this
case'. What I'm trying to find out is what the actual course of events
was for C, so I can give glib answers to people (:-))
--tim
2:05 p.m.
On Thu, 5 Sep 2002, Tim Bradshaw wrote:
* Johnny Billquist wrote:
[...]
Ah. Ok, now I understand what you're asking for.
You want to know what the first C was written in, and what that
compiler/assembler was written in/on, and so on...
No, I'm just deducting. Since the reference posted said that TMG was the
first higher level language implemented, it follows that it must have been
written in a low level language, namely assembler.
Admittedly, the PDP-7 TMG *could* have been written in some high level
language on some other machine using some tool that made a PDP-7
executable, so your guess is as good as mine.
But even though I cannot account for all steps, I can guarantee that at
the end of the chain, you *will* find assembler.
I guess my MACRO-11 implementation of C isn't good enough. :-)
(Well, it ain't mine, it's the normal DECUS C, but I'm hacked some at it.)
Johnny
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
How? It was written, of course. In assembler. By
that time, you already
had the assembler, an editor, and other commonly used system programs, so
it's just a case of the normal development cycle.
Is this known or is it deduction? 
9 Sep
9 Sep
11:17 p.m.
On 2002-Sep-05 09:11:38 -0700, Michael Davidson <MichaelDavidson(a)pacbell.net>
wrote:
Johnny Billquist wrote:
Actually, to use one of the other "first stored-program computer"
candidates, EDSAC provided what I consider to be a very sophisticated
assembler/loader that read programs off paper tape into memory. This
assembler/loader ("initial orders") was 41 instructions long and was
hard-wired onto uniselectors which were automatically loaded into
memory when the start switch was pressed.
It supported:
- single-letter mnemonics for each of the 18 instructions
- decimal entry of numbers (EDSAC was binary internally)
- 13 single-letter variables which could be assigned or added to the
address in each instruction.
- program relocation (courtesy of the above)
Overall, the input language looks much closer to assembler language
than the instruction bit patterns in memory. (The Mathematical
Laboratory also developed an extensive collection of reusable
subroutines intended to simplify program development).
Ref: "The Preparation of Programs for an Electronic Digital Computer",
M.V. Wilkes, D.J. Wheeler, S. Gill, Addison-Wesley, 1951.
A rummage around on the WEB will turn up a couple of EDSAC simulators
and sample programs.
Peter
But even though I cannot account for all steps, I
can guarantee that at
the end of the chain, you *will* find assembler.
Or, just possibly, Alan Turing hand punching Mark 1 machine code onto
paper tape ;-)
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9 comments
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participants (7)
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Johnny Billquist -
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Peter Jeremy -
Tim Bradshaw -
Tim Bradshaw -
Warren Toomey