6 ms·

Fred Brooks is mentioned in the case study. The book "The Mythical Man Month" is about software engineering and project management based on Fred Brooks experie

by Cactus2018 8y ago

Fred Brooks is mentioned in the case study. The book "The Mythical Man Month" is about software engineering and project management based on Fred Brooks experiences at IBM while managing the development of OS/360. > assigning more programmers to a project running behind schedule will make it even later. > while it takes one woman nine months to make one baby, "nine women can't make a baby in one month". https://en.wikipedia.org/wiki/The_Mythical_Man-Month https://en.wikipedia.org/wiki/The_Mythical_Man-Month

wglb 8y ago
The book is essentially an apologia for finishing one year late.
- graycat 8y ago
  And he ended up with JCL, one of the worst pieces of work in computing. There were already much better user interfaces then.
  - wglb 8y ago
    In those days? Can you give an example?
    - graycat 8y ago
      DEC10
      - msla 8y ago
        The PDP-10 family ran a few operating systems in its life, some of which had better or worse user interfaces, but one of the things the all had in common was a focus on interactive use as opposed to batch operation or even block-mode terminals. Interactive use means each concurrent user represents more system load compared to the alternatives.
      - wglb 8y ago
        The pdp 10 was introduced in 1966. DOS/360 was introduced in 1964, prior to the PDP 10. Thus, there was nothing to borrow when JCL was invented. Again, what examples of existing languages were available at the time the JCL was invented?
        jecel 8y ago
        https://en.wikipedia.org/wiki/Work_Flow_Language https://en.wikipedia.org/wiki/Work_Flow_Language It says this was introduced "soon after 1961", though I doubt the IBM people were aware of it.
  - DrScump 8y ago
    JCL wasn't a user interface; only programmers used it. It was essentially shell scripting and environment variables.
    - graycat 8y ago
      It was the interface for users essentially all of whom were programmers since there was essentially no on-line access then. Calling JCL a scripting language is one heck of an insult to Rexx, etc. When Cowlishaw's Rexx became available right, away it swept IBM, e.g., ran the service machines that ran VNET, IBM's early thing to do internally for IBM what the Internet later did for the world. Rexx could have run on MVS, etc. -- some people at Watson wanted that, but I doubt if it ever did. I wrote a lot of JCL for MVT on the 360/91 and later on other 360 boxes, and I never saw anything like environment variables. The horror was the DCB statements: They were to fill in control blocks needed in assembler to do I/O; if didn't understand those assembler control blocks, then DCB statements didn't make a lot of sense.
      - DrScump 8y ago
        Perhaps I should clarify that I was referring to OS/MVS JCL. MVT was before my time. By "environment variables" I meant the ability to tie a logical device name (at the program level) to a physical device (or instance thereof, like a particular generation of a tape volume), like how environment variables link a logical name to a value. I used to do all the JCL for my project group. Having come from being an operator first, I knew how to set up the JCL exactly how I wanted (including comments for instructions to / clarifications for operators and job control center staff) and syntax-test it. Meanwhile, the other groups stumbled through either hand-keypunching or laboriously filling out keypunch sheets. Many didn't even know we had a JES2 spooled card punch available before I came in.
        graycat 8y ago
        The worst pain in the back side for me with JCL was that the job turnaround time was about 4 hours. So, miss one comma in JCL, and KaPOOF lose 4 hours of work. I had two solutions: (1) Walk my deck of cards to a card/printer remote terminal (about 300 yards away from my office) and have it print my card deck, then back at my office stare closely character by character by character at the printout. (2) When a job did run, rush to copy the crucial JCL cards and KEEP them as something that WORKED. In those days, the job control card struggles were not just for MVT or MVS but more general. At one meeting of users, a guy stood and said that he wanted the control cards that worked laminated in plastic with a hole in a corner and hung on a chain!!! My later encounters with the IBM mainframes were via 3270 terminals, VM, Rexx, and with nearly no use of JCL. And in those days I was becoming a happy as a clam Prime customer. Did some good things with some Prime computers. Then it was on to PC/DOS, OS/2, and Windows 9X, 2000, XP, 7, 10, .NET, SQL Server, the .NET version of Visual Basic (as far as I can tell, just a better flavor of syntactic sugar than C# -- I hate the idosyncratic syntax of C/C# -- wrote it? Yes. Like it, NO!), and soon Windows Server. Here in the Mid Hudson Valley, IBM is running ads for people who know CICS to rejoin!!
  - edward-h 8y ago
    You might be pleased to hear Fred Brooks apologised for JCL in 2015:[1] > If we had been smart, we would also have done a schedule-time mode of PL/I instead of doing JCL, the Job Control Language. But we weren’t smart. The worst mistake we made was JCL. Its existence was a mistake. Building it on a card format was a mistake. Building it on assembly language was a mistake. Thinking of it as only six little control cards instead of a language was a mistake, because it had no proper subroutine facilities, no proper branching facilities. That we did not see it as a language was the fundamental problem; we saw it as a set of control cards. [1] https://cacm.acm.org/magazines/2015/11/193333-an-interview-with-fred-brooks/abstract https://cacm.acm.org/magazines/2015/11/193333-an-interview-w...
    - gwern 8y ago
      The full interview is at https://archive.computerhistory.org/resources/access/text/2012/11/102658255-05-01-acc.pdf https://archive.computerhistory.org/resources/access/text/20... ; I've mirrored the ACM excerpts at https://www.gwern.net/docs/cs/2015-brooks.pdf https://www.gwern.net/docs/cs/2015-brooks.pdf
    - graycat 8y ago
      Thank you; thank you; thank you. There he really nailed the problems with JCL. Once at the Watson lab I rode in the elevator with Brooks and nearly kissed his ring for his The Mythical Man-Month but was nice enough not to mention JCL!
  - sreeramvenkat 8y ago
    Sometimes I wonder if anyone can write a JCL from scratch. A new JCL is always copied from an existing one and the gets modified. The first couple of lines of a JCL are particularly scary if I recollect properly.

wglb 8y ago

The book is essentially an apologia for finishing one year late.

graycat 8y ago
And he ended up with JCL, one of the worst pieces of work in computing. There were already much better user interfaces then.
- wglb 8y ago
  In those days? Can you give an example?
  - graycat 8y ago
    DEC10
    - msla 8y ago
      The PDP-10 family ran a few operating systems in its life, some of which had better or worse user interfaces, but one of the things the all had in common was a focus on interactive use as opposed to batch operation or even block-mode terminals. Interactive use means each concurrent user represents more system load compared to the alternatives.
    - wglb 8y ago
      The pdp 10 was introduced in 1966. DOS/360 was introduced in 1964, prior to the PDP 10. Thus, there was nothing to borrow when JCL was invented. Again, what examples of existing languages were available at the time the JCL was invented?
      - jecel 8y ago
        https://en.wikipedia.org/wiki/Work_Flow_Language https://en.wikipedia.org/wiki/Work_Flow_Language It says this was introduced "soon after 1961", though I doubt the IBM people were aware of it.
- DrScump 8y ago
  JCL wasn't a user interface; only programmers used it. It was essentially shell scripting and environment variables.
  - graycat 8y ago
    It was the interface for users essentially all of whom were programmers since there was essentially no on-line access then. Calling JCL a scripting language is one heck of an insult to Rexx, etc. When Cowlishaw's Rexx became available right, away it swept IBM, e.g., ran the service machines that ran VNET, IBM's early thing to do internally for IBM what the Internet later did for the world. Rexx could have run on MVS, etc. -- some people at Watson wanted that, but I doubt if it ever did. I wrote a lot of JCL for MVT on the 360/91 and later on other 360 boxes, and I never saw anything like environment variables. The horror was the DCB statements: They were to fill in control blocks needed in assembler to do I/O; if didn't understand those assembler control blocks, then DCB statements didn't make a lot of sense.
    - DrScump 8y ago
      Perhaps I should clarify that I was referring to OS/MVS JCL. MVT was before my time. By "environment variables" I meant the ability to tie a logical device name (at the program level) to a physical device (or instance thereof, like a particular generation of a tape volume), like how environment variables link a logical name to a value. I used to do all the JCL for my project group. Having come from being an operator first, I knew how to set up the JCL exactly how I wanted (including comments for instructions to / clarifications for operators and job control center staff) and syntax-test it. Meanwhile, the other groups stumbled through either hand-keypunching or laboriously filling out keypunch sheets. Many didn't even know we had a JES2 spooled card punch available before I came in.
      - graycat 8y ago
        The worst pain in the back side for me with JCL was that the job turnaround time was about 4 hours. So, miss one comma in JCL, and KaPOOF lose 4 hours of work. I had two solutions: (1) Walk my deck of cards to a card/printer remote terminal (about 300 yards away from my office) and have it print my card deck, then back at my office stare closely character by character by character at the printout. (2) When a job did run, rush to copy the crucial JCL cards and KEEP them as something that WORKED. In those days, the job control card struggles were not just for MVT or MVS but more general. At one meeting of users, a guy stood and said that he wanted the control cards that worked laminated in plastic with a hole in a corner and hung on a chain!!! My later encounters with the IBM mainframes were via 3270 terminals, VM, Rexx, and with nearly no use of JCL. And in those days I was becoming a happy as a clam Prime customer. Did some good things with some Prime computers. Then it was on to PC/DOS, OS/2, and Windows 9X, 2000, XP, 7, 10, .NET, SQL Server, the .NET version of Visual Basic (as far as I can tell, just a better flavor of syntactic sugar than C# -- I hate the idosyncratic syntax of C/C# -- wrote it? Yes. Like it, NO!), and soon Windows Server. Here in the Mid Hudson Valley, IBM is running ads for people who know CICS to rejoin!!
- edward-h 8y ago
  You might be pleased to hear Fred Brooks apologised for JCL in 2015:[1] > If we had been smart, we would also have done a schedule-time mode of PL/I instead of doing JCL, the Job Control Language. But we weren’t smart. The worst mistake we made was JCL. Its existence was a mistake. Building it on a card format was a mistake. Building it on assembly language was a mistake. Thinking of it as only six little control cards instead of a language was a mistake, because it had no proper subroutine facilities, no proper branching facilities. That we did not see it as a language was the fundamental problem; we saw it as a set of control cards. [1] https://cacm.acm.org/magazines/2015/11/193333-an-interview-with-fred-brooks/abstract https://cacm.acm.org/magazines/2015/11/193333-an-interview-w...
  - gwern 8y ago
    The full interview is at https://archive.computerhistory.org/resources/access/text/2012/11/102658255-05-01-acc.pdf https://archive.computerhistory.org/resources/access/text/20... ; I've mirrored the ACM excerpts at https://www.gwern.net/docs/cs/2015-brooks.pdf https://www.gwern.net/docs/cs/2015-brooks.pdf
  - graycat 8y ago
    Thank you; thank you; thank you. There he really nailed the problems with JCL. Once at the Watson lab I rode in the elevator with Brooks and nearly kissed his ring for his The Mythical Man-Month but was nice enough not to mention JCL!
- sreeramvenkat 8y ago
  Sometimes I wonder if anyone can write a JCL from scratch. A new JCL is always copied from an existing one and the gets modified. The first couple of lines of a JCL are particularly scary if I recollect properly.