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I think of PL/I as a systems programming language, and COBOL as an application programming language, much in the same way you'd look at C/C++ and Java in the Un

by Aloha 5y ago

I think of PL/I as a systems programming language, and COBOL as an application programming language, much in the same way you'd look at C/C++ and Java in the Unix world, I think (I think that analogy is actually almost directly applicable, though maybe Pascal is a closer fit? I'm not sure). Different tools designed to do different things. I'd actually like to learn PL/I (or COBOL beyond a cursory knowledge), I'm someone who has a great deal of knowledge of the thought patterns of programming (as well as how you architect software, systems design, etc), without knowing any one tool well, I tend to learn a tool for a task, then forget the tool when I no longer require it anymore. My job is.. hard to explain, but its quasi programming, but also very much not aside from helper scripts I write now and again (I use all of the thought patterns of programming, without any of the tools). I enjoy writing software, but only have so many itches to scratch in my personal time.

skissane 5y ago
> I think of PL/I as a systems programming language, and COBOL as an application programming language, much in the same way you'd look at C/C++ and Java in the Unix world, I think PL/I is a general purpose applications programming language. Its primary design goal was to unify COBOL, FORTRAN and ALGOL into a single language, and as such was intended to meet the needs of both business and scientific application programmers. IBM invested heavily in trying to convince business software developers to move from COBOL to PL/I - see for example [0] - but, while there was a decent amount of business software development done using PL/I in the 1970s, it never had the success in that market which IBM had hoped for, PL/I ended up being an also-ran to COBOL instead of what it was meant to be, the successor. PL/I proper was generally not used as a systems programming language. On the one hand, it had a number of features (decimal arithmetic, formatted and record IO and multithreading support built-in to the language syntax) which while useful in applications programming were unavailable or unsupportable or not useful in systems programming. On the other hand, a lot of features which are valuable in systems programming - such as inline assembly, the ability to manually control the allocation of variables to machine registers - are not in PL/I proper. Given this, it was common to create systems programming dialects of PL/I which removed those application-centric features and added systems programming specific features. But those dialects were not properly speaking PL/I and were often called by other names - IBM’s was called BSL, later renamed to PL/S, which spawned a bunch of descendants with similar names (PL/AS, PL/X, PL/DS, PL/MI, PL/MP, PL.8). Honeywell had PL/6 which was used as the systems programming language for its CP-6 operating system (a backward compatible rewrite of Xerox CP-V). Prime Computer had PL/P as the systems programming language for PRIMOS. Gary Kildall developed PL/M in which he wrote the first versions of CP/M (later versions were rewritten in assembly to get better performance, but even in later versions PL/M was still used to implement some of the utilities.) However, none of these systems programming languages were in the strictest sense PL/I; the original unmodified PL/I (without subsetting or supersetting) was an applications programming language not a systems programming language. [0] http://bitsavers.org/pdf/ibm/360/pli/SC20-1651-1_A_Guide_to_PL_I_for_Commercial_Programmers_Apr68.pdf http://bitsavers.org/pdf/ibm/360/pli/SC20-1651-1_A_Guide_to_...
- Aloha 5y ago
  Thank you for taking the time to explain that to me! I found it informative and enjoyable to read.

by Aloha 5y ago

skissane 5y ago

> I think of PL/I as a systems programming language, and COBOL as an application programming language, much in the same way you'd look at C/C++ and Java in the Unix world, I think PL/I is a general purpose applications programming language. Its primary design goal was to unify COBOL, FORTRAN and ALGOL into a single language, and as such was intended to meet the needs of both business and scientific application programmers. IBM invested heavily in trying to convince business software developers to move from COBOL to PL/I - see for example [0] - but, while there was a decent amount of business software development done using PL/I in the 1970s, it never had the success in that market which IBM had hoped for, PL/I ended up being an also-ran to COBOL instead of what it was meant to be, the successor. PL/I proper was generally not used as a systems programming language. On the one hand, it had a number of features (decimal arithmetic, formatted and record IO and multithreading support built-in to the language syntax) which while useful in applications programming were unavailable or unsupportable or not useful in systems programming. On the other hand, a lot of features which are valuable in systems programming - such as inline assembly, the ability to manually control the allocation of variables to machine registers - are not in PL/I proper. Given this, it was common to create systems programming dialects of PL/I which removed those application-centric features and added systems programming specific features. But those dialects were not properly speaking PL/I and were often called by other names - IBM’s was called BSL, later renamed to PL/S, which spawned a bunch of descendants with similar names (PL/AS, PL/X, PL/DS, PL/MI, PL/MP, PL.8). Honeywell had PL/6 which was used as the systems programming language for its CP-6 operating system (a backward compatible rewrite of Xerox CP-V). Prime Computer had PL/P as the systems programming language for PRIMOS. Gary Kildall developed PL/M in which he wrote the first versions of CP/M (later versions were rewritten in assembly to get better performance, but even in later versions PL/M was still used to implement some of the utilities.) However, none of these systems programming languages were in the strictest sense PL/I; the original unmodified PL/I (without subsetting or supersetting) was an applications programming language not a systems programming language. [0] http://bitsavers.org/pdf/ibm/360/pli/SC20-1651-1_A_Guide_to_PL_I_for_Commercial_Programmers_Apr68.pdf http://bitsavers.org/pdf/ibm/360/pli/SC20-1651-1_A_Guide_to_...

Aloha 5y ago
Thank you for taking the time to explain that to me! I found it informative and enjoyable to read.