4 ms·

The alternative to C for systems programming in the '70s was not Modula-2 or anything like it, the only realistic alternative for most production systems was wr

by mwfunk 11y ago

The alternative to C for systems programming in the '70s was not Modula-2 or anything like it, the only realistic alternative for most production systems was writing your kernel code in assembly. C allowed the industry to finally stop defaulting to assembly for systems programming. That was a very good thing, regardless of how old and inappropriate C might be for such purposes nowadays. The comment you were responding to reads to me like someone providing historical context, not an expression of an ideal.

nickpsecurity 11y ago
"The alternative to C for systems programming in the '70s was not Modula-2 or anything like it" The main alternatives were ALGOL60, ALGOL68, and Pascal. They were each designed by people who knew what they were doing in balancing many goals. They, esp ALGOLS, achieved good chunk of most. A subset and/or modification of one with gradual progression for improved hardware would've led to better results than C with same amount of labor invested. On low end, Pascal ended up being ported to systems from 8-bitters to mainframes. On high end, Burroughs implemented their mainframe OS in an ALGOL with hardware that enforced its safety for arrays, stacks, and function calls. In the 80's, things like Modula-2, Concurrent Pascal, Oberon, and Ada showed up. I'll understand if they avoided Ada given constraints at the time but the others were safer than C and quite efficient. More importantly, their authors could've used your argument back then as most people were doing but decided to build on prior work with better design. They got better results out of it, too, with many doing a lot of reliable code with very little manpower. Hansen topped it off by implementing a barebones, Wirth-like language and system called Edison on the same PDP that C was born on. "The comment you were responding to reads to me like someone providing historical context, not an expression of an ideal." The historical context in a related comment was wrong, though. It almost always is with C because people don't know it's true history. Revisionism took over. The power that revision has in locking in people to C is why I always counter it with actual evidence from the inventors of the concepts. Two quick questions to illustrate why I do that and test if it's sensible: 1. When hearing "the programmer is in control," did you think that philosophy was invented by Thompson for C or it was stolen without early credit from BCPL along with its other foundations? 2. Did you know that those were not designed or validated as a good language at all? And that they were grudgingly accepted just to get CPL, an ALGOL60 variant, to compile on crappy hardware whose problems no longer exist by chopping off most important attributes? If you knew 1 and 2, would you still think C was a "well-designed" language for systems programming? Or a failed implementation of ALGOL60 whose designers were too limited by hardware? If No 1, we should emulate the heck out of C. If No 2, we should emulate ALGOL60-like language that balances readability, efficiency, safety, and programming in the large. Btw, all the modern languages people think are productive and safer lean more toward ALGOL more than C albeit sometimes using C-like syntax for uptake. Might be corroboration of what I'm saying.
- FullyFunctional 11y ago
  I actually mostly agree with you. My point was poorly made. I didn't mean that C was particularily great, only that it "won" and having a winner meant more portable code. I'll back out of the PL debate; this isn't really the place and there's too much to be said on the topic than will fit in this margin.
  - nickpsecurity 11y ago
    "only that it "won" and having a winner meant more portable code." That's generally true so long as the winner is open. C was. Now, it runs on everything.
- kps 11y ago
  > [...] or it was stolen without early credit from BCPL along with its other foundations? That's simply not correct. The first public paper on C (The C Programming Language in BSTJ #57, the Unix issue) spent the first 4-page section on its BCPL ancestry.
  - nickpsecurity 11y ago
    It's a contested claim. However, here's the first document and reference on the C language: https://www.bell-labs.com/usr/dmr/www/cman.pdf https://www.bell-labs.com/usr/dmr/www/cman.pdf Show me where it references BCPL. As I see it, Ritchie only references B as the inspiration for C. From the document, anyone who hadn't read the B paper (most people) would think they, Thompson, and/or Ritchie mostly came up with C's features and strengths. They eventually became known as the "C philosophy" and C-like languages. Whereas, it was Martin Richards that invented both of those plus the idea of stripped down languages for writing tools on minimal hardware. He should get credit for creating the "BCPL philosophy" that the "programmer is in control" plus inspiring a BCPL-like language called C that allowed UNIX's success. Instead, early work focused all attention on Thompson and Ritchie with UNIX papers/software making sure that was the case by adding momentum. At least I got to see the guy in action in the video linked to my History of C page. It shows his team, the constraints they worked on, why they dumped most of ALGOL, and him working with it later on. That presentation put things into an honest perspective where I can see his and UNIX founders' contributions to overall success with due credits (and/or critiques) to each.
Gibbon1 11y ago
One of the things about C was: American Telephone and Telegraph Company was a regulated monopoly and prohibited from selling anything outside of the telephony business. So they developed C and Unix but couldn't sell either commercially. However they could allow universities to use both for free. Deal with C was one grad student could write a cross compiler in about 300 hours. And then you could use that to cross compile Unix and the compiler. End result a lot of CS students learned C in school. Other languages tended to be tied to a particular machine, cost money, or weren't really suitable (Fortran/p-system Pascal) for the stuff people wanted to do.
pjmlp 11y ago
That is an urban legend perpetrated by C fans rewriting history. Extended Algol was available in 1961. PL/I and PL/M variants are older than C. Mesa was already being used at Xerox PARC when C was born. There are quite a few other examples that anyone that bothers to read SIGPLAN papers and other archives can easily find out.
- kps 11y ago
  > Extended Algol was available in 1961. What extension was that? Burrough's ESPOL (the notable use of an Algol extension for system programming, on a processor designed to be an Algol target) had what we would now call inline assembly. > Mesa was already being used at Xerox PARC when C was born. Close; C ~ 1972 (started 1969), Mesa ~ 1976 (started 1971). The Alto system software was mostly BCPL; Mesa arrived with the commercial D series. Mesa also targeted a virtual instruction set (i.e. like Java or p-code) designed specifically for it, run by an interpreter on the bare metal.
  - pjmlp 11y ago
    Burroughs had Extended Algol and ESPOL, yes. It still doesn't invalidate the fact that it had more memory safety features as C, one decade earlier. Regarding Mesa that is like calling x86/x64 firmware an interpreter for Intel bytecode. Most literature in those days used bytecode to refer to Assembly processed by CPU microcode.
    - kps 11y ago
      The point was that those machines had the benefit of instruction sets co-designed with the language. (And Mesa had strong default type safety, but basically the same memory model as C, allowing pointer arithmetic, null pointers, and dangling pointers.)
      - pjmlp 11y ago
        Of course Mesa had pointer arithmetic, null and dagling pointers. Any systems programming language has them. However there is a difference between having them as an addition to strong type features and them being the only way to program in the language. For example, using arrays and strings didn't require pointer arithmetic. In C all unsafe features are in thr face of the programmer. There is no way to avoid them. In Mesa and other similar languages, those unsafe are there, but programmers only need to use them in a few cases. C was designed with PDP-11 instruction set in mind. For many years that the C machine model no longer maps to the hardware as many think it does.
kjs3 11y ago
That's laughably untrue. In fact, in the 70s, most system programming was done in anything except C. Off the top of my head: IBM: assembler & PL/S Unisys: Algol GE/MIT (Multics): PL/I(-ish) Control Data: Cybill (Pascal-ish) & assembler Intel and Digital Research: PL/M DEC: MACRO-11 & BLISS DG: assembly & PL/I Xerox: assembly, Smalltalk, Mesa/Cedar PERQ: Pascal

by mwfunk 11y ago

nickpsecurity 11y ago

"The alternative to C for systems programming in the '70s was not Modula-2 or anything like it" The main alternatives were ALGOL60, ALGOL68, and Pascal. They were each designed by people who knew what they were doing in balancing many goals. They, esp ALGOLS, achieved good chunk of most. A subset and/or modification of one with gradual progression for improved hardware would've led to better results than C with same amount of labor invested. On low end, Pascal ended up being ported to systems from 8-bitters to mainframes. On high end, Burroughs implemented their mainframe OS in an ALGOL with hardware that enforced its safety for arrays, stacks, and function calls. In the 80's, things like Modula-2, Concurrent Pascal, Oberon, and Ada showed up. I'll understand if they avoided Ada given constraints at the time but the others were safer than C and quite efficient. More importantly, their authors could've used your argument back then as most people were doing but decided to build on prior work with better design. They got better results out of it, too, with many doing a lot of reliable code with very little manpower. Hansen topped it off by implementing a barebones, Wirth-like language and system called Edison on the same PDP that C was born on. "The comment you were responding to reads to me like someone providing historical context, not an expression of an ideal." The historical context in a related comment was wrong, though. It almost always is with C because people don't know it's true history. Revisionism took over. The power that revision has in locking in people to C is why I always counter it with actual evidence from the inventors of the concepts. Two quick questions to illustrate why I do that and test if it's sensible: 1. When hearing "the programmer is in control," did you think that philosophy was invented by Thompson for C or it was stolen without early credit from BCPL along with its other foundations? 2. Did you know that those were not designed or validated as a good language at all? And that they were grudgingly accepted just to get CPL, an ALGOL60 variant, to compile on crappy hardware whose problems no longer exist by chopping off most important attributes? If you knew 1 and 2, would you still think C was a "well-designed" language for systems programming? Or a failed implementation of ALGOL60 whose designers were too limited by hardware? If No 1, we should emulate the heck out of C. If No 2, we should emulate ALGOL60-like language that balances readability, efficiency, safety, and programming in the large. Btw, all the modern languages people think are productive and safer lean more toward ALGOL more than C albeit sometimes using C-like syntax for uptake. Might be corroboration of what I'm saying.

FullyFunctional 11y ago
I actually mostly agree with you. My point was poorly made. I didn't mean that C was particularily great, only that it "won" and having a winner meant more portable code. I'll back out of the PL debate; this isn't really the place and there's too much to be said on the topic than will fit in this margin.
- nickpsecurity 11y ago
  "only that it "won" and having a winner meant more portable code." That's generally true so long as the winner is open. C was. Now, it runs on everything.
kps 11y ago
> [...] or it was stolen without early credit from BCPL along with its other foundations? That's simply not correct. The first public paper on C (The C Programming Language in BSTJ #57, the Unix issue) spent the first 4-page section on its BCPL ancestry.
- nickpsecurity 11y ago
  It's a contested claim. However, here's the first document and reference on the C language: https://www.bell-labs.com/usr/dmr/www/cman.pdf https://www.bell-labs.com/usr/dmr/www/cman.pdf Show me where it references BCPL. As I see it, Ritchie only references B as the inspiration for C. From the document, anyone who hadn't read the B paper (most people) would think they, Thompson, and/or Ritchie mostly came up with C's features and strengths. They eventually became known as the "C philosophy" and C-like languages. Whereas, it was Martin Richards that invented both of those plus the idea of stripped down languages for writing tools on minimal hardware. He should get credit for creating the "BCPL philosophy" that the "programmer is in control" plus inspiring a BCPL-like language called C that allowed UNIX's success. Instead, early work focused all attention on Thompson and Ritchie with UNIX papers/software making sure that was the case by adding momentum. At least I got to see the guy in action in the video linked to my History of C page. It shows his team, the constraints they worked on, why they dumped most of ALGOL, and him working with it later on. That presentation put things into an honest perspective where I can see his and UNIX founders' contributions to overall success with due credits (and/or critiques) to each.

Gibbon1 11y ago

One of the things about C was: American Telephone and Telegraph Company was a regulated monopoly and prohibited from selling anything outside of the telephony business. So they developed C and Unix but couldn't sell either commercially. However they could allow universities to use both for free. Deal with C was one grad student could write a cross compiler in about 300 hours. And then you could use that to cross compile Unix and the compiler. End result a lot of CS students learned C in school. Other languages tended to be tied to a particular machine, cost money, or weren't really suitable (Fortran/p-system Pascal) for the stuff people wanted to do.

pjmlp 11y ago

That is an urban legend perpetrated by C fans rewriting history. Extended Algol was available in 1961. PL/I and PL/M variants are older than C. Mesa was already being used at Xerox PARC when C was born. There are quite a few other examples that anyone that bothers to read SIGPLAN papers and other archives can easily find out.

kps 11y ago
> Extended Algol was available in 1961. What extension was that? Burrough's ESPOL (the notable use of an Algol extension for system programming, on a processor designed to be an Algol target) had what we would now call inline assembly. > Mesa was already being used at Xerox PARC when C was born. Close; C ~ 1972 (started 1969), Mesa ~ 1976 (started 1971). The Alto system software was mostly BCPL; Mesa arrived with the commercial D series. Mesa also targeted a virtual instruction set (i.e. like Java or p-code) designed specifically for it, run by an interpreter on the bare metal.
- pjmlp 11y ago
  Burroughs had Extended Algol and ESPOL, yes. It still doesn't invalidate the fact that it had more memory safety features as C, one decade earlier. Regarding Mesa that is like calling x86/x64 firmware an interpreter for Intel bytecode. Most literature in those days used bytecode to refer to Assembly processed by CPU microcode.
  - kps 11y ago
    The point was that those machines had the benefit of instruction sets co-designed with the language. (And Mesa had strong default type safety, but basically the same memory model as C, allowing pointer arithmetic, null pointers, and dangling pointers.)
    - pjmlp 11y ago
      Of course Mesa had pointer arithmetic, null and dagling pointers. Any systems programming language has them. However there is a difference between having them as an addition to strong type features and them being the only way to program in the language. For example, using arrays and strings didn't require pointer arithmetic. In C all unsafe features are in thr face of the programmer. There is no way to avoid them. In Mesa and other similar languages, those unsafe are there, but programmers only need to use them in a few cases. C was designed with PDP-11 instruction set in mind. For many years that the C machine model no longer maps to the hardware as many think it does.

kjs3 11y ago

That's laughably untrue. In fact, in the 70s, most system programming was done in anything except C. Off the top of my head: IBM: assembler & PL/S Unisys: Algol GE/MIT (Multics): PL/I(-ish) Control Data: Cybill (Pascal-ish) & assembler Intel and Digital Research: PL/M DEC: MACRO-11 & BLISS DG: assembly & PL/I Xerox: assembly, Smalltalk, Mesa/Cedar PERQ: Pascal