Goals: Systems programming aims at students who are proficient in an object-oriented programming language like Java or Python, and have completed a course on data structures, but would like a deeper understanding of how "real world" computing systems are built. In CS4414 you will learn an additional programming language, C++, and will learn to use the Linux system as a way to create high quality software, with an emphasis on parallelism and other ways of maximizing performance. The C++ with Linux technology pair has gained nearly universal adoption at every level, from small devices hidden within "smart things" to the world’s largest cloud computing systems. As such, the skills you gain in CS4414 are very broadly relevant, no matter what you plan to do in your career.
Prequisites: We aim at two groups of students. One group will have already taken CS3110 and CS3410 (or the equivalent), done some substantial coding projects in Java and also in a language like C (with real pointers, malloc and free), and are seeking additional perspective on the creation of large, complex, software systems. These students would have gained extensive programming experience along the way and will be very comfortable in object-oriented programming. A second group might have less formal background, but already be sure they can handle a more advanced programming class. Such a person could enroll in CS4414 fairly early, before taking 3410, but after discovering a significant love for and talent for "hard core" programming.
We do see some students who have already taken CS4410. For them, some ideas we cover will be familiar, but in fact the overlap is surprisingly small. CS4410 focuses on how the OS was built, not on how to use it very effectively to achieve the highest possible performance. This shift in emphasis leads to material you won’t have seen in CS4410. On the other hand, both courses do look closely at Posix threads and monitor-style synchronization. One difference is that in CS4410, that topic is treated mostly "on paper". In CS4414, we program with threads, almost from the start of the semester.
Coding test on the first day: CS4414 can be problematic for students who are not yet confident programmers with a good level of understanding of computing environments and tools, and the ability to pick things up with relatively little direct guidance. That sort of student should first get more experience — CS4414 is not an easy class, moves very quickly, and has a lot of hands-on programming assignments (CS4410, in contrast, actually has very little coding unless you take CS4411 at the same time). CS4414 is absolutely not the place to develop basic programming and object oriented computing skills. You will fall behind quickly if you lack that sort of prior background and experience. To ensure that everyone is at the right level, there will be a coding assignment on the very first day of the class — a kind of "readiness test" (it will be pass/fail). People unable to complete this test shouldn’t enroll in CS4414.
Some practical considerations: Among our practical goals will to learn to leverage existing Linux tools, to learn how to write correct code in C++, and how to achieve performance and efficiency. Like any programming language, you really teach yourself by doing, but we will present C++ and Linux in the required section. Assigned readings and homeworks will help you build up hands-on proficiency. C++ and Linux are easy to learn if you are comfortable in some other object oriented programming language like Java, so we will move quickly (this is not a course for people who struggle with programming or who have never seen object-oriented code and learned about data structures). You’ll also be reading a famous C++ self-teaching textbook, written by the inventor of the language. This will begin early in the semester, so be ready to work hard in the first few weeks!
Goals: Systems programming aims at students who are proficient in an object-oriented programming language like Java or Python, and have completed a course on data structures, but would like a deeper understanding of how "real world" computing systems are built. In CS4414 you will learn an additional programming language, C++, and will learn to use the Linux system as a way to create high quality software, with an emphasis on parallelism and other ways of maximizing performance. The C++ with Linux technology pair has gained nearly universal adoption at every level, from small devices hidden within "smart things" to the world’s largest cloud computing systems. As such, the skills you gain in CS4414 are very broadly relevant, no matter what you plan to do in your career.
Prequisites: We aim at two groups of students. One group will have already taken CS3110 and CS3410 (or the equivalent), done some substantial coding projects in Java and also in a language like C (with real pointers, malloc and free), and are seeking additional perspective on the creation of large, complex, software systems. These students would have gained extensive programming experience along the way and will be very comfortable in object-oriented programming. A second group might have less formal background, but already be sure they can handle a more advanced programming class. Such a person could enroll in CS4414 fairly early, before taking 3410, but after discovering a significant love for and talent for "hard core" programming.
We do see some students who have already taken CS4410. For them, some ideas we cover will be familiar, but in fact the overlap is surprisingly small. CS4410 focuses on how the OS was built, not on how to use it very effectively to achieve the highest possible performance. This shift in emphasis leads to material you won’t have seen in CS4410. On the other hand, both courses do look closely at Posix threads and monitor-style synchronization. One difference is that in CS4410, that topic is treated mostly "on paper". In CS4414, we program with threads, almost from the start of the semester.
Coding test on the first day: CS4414 can be problematic for students who are not yet confident programmers with a good level of understanding of computing environments and tools, and the ability to pick things up with relatively little direct guidance. That sort of student should first get more experience — CS4414 is not an easy class, moves very quickly, and has a lot of hands-on programming assignments (CS4410, in contrast, actually has very little coding unless you take CS4411 at the same time). CS4414 is absolutely not the place to develop basic programming and object oriented computing skills. You will fall behind quickly if you lack that sort of prior background and experience. To ensure that everyone is at the right level, there will be a coding assignment on the very first day of the class — a kind of "readiness test" (it will be pass/fail). People unable to complete this test shouldn’t enroll in CS4414.
Some practical considerations: Among our practical goals will to learn to leverage existing Linux tools, to learn how to write correct code in C++, and how to achieve performance and efficiency. Like any programming language, you really teach yourself by doing, but we will present C++ and Linux
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Answers
System Call via unistd.h:
Advantages:
Direct system calls (e.g., getenv, setenv) can be more efficient as they interact directly with the operating system kernel.
Provides low-level control and access to environment variables.
Disadvantages:
May require more code and error handling compared to higher-level alternatives.
Less portable as system calls can vary across different operating systems.
Justification: Use unistd.h for low-level control and efficiency when performance is critical, and you need to interact with the environment variables at a very low level. This is typically necessary in systems programming or when writing low-level utilities.
Library Routine via stdlib.h:
Advantages:
Higher-level and more portable than system calls, as the library routines abstract OS-specific details.
Easier to use and less error-prone for basic operations.
Disadvantages:
Slightly less efficient than system calls, but the difference is often negligible.
Justification: Utilize stdlib.h when you need a balance between ease of use and portability. This is suitable for most general-purpose programming tasks, where the efficiency gain of using system calls is not a critical concern.
Shell (e.g., via command-line tools):
Advantages:
User-friendly for manual or script-based interactions.
Great for one-off tasks or quick testing.
Disadvantages:
Limited to the capabilities of the shell and its utilities.
Not suitable for programmatic, embedded, or highly performance-critical tasks.
Justification: Employ a shell or command-line tools when you need a quick and convenient way to interact with environment variables, especially for manual or script-based tasks. However, avoid this method for more complex, programmatic, or performance-critical applications.
In summary, the choice of whether to use a system call via unistd.h, a library routine via stdlib.h, or a shell to access and manipulate environment variables depends on your specific needs. Consider the trade-offs in terms of performance, portability, and ease of use to determine the most suitable approach for your task.
a) Opcode: An opcode, short for "operation code," is a fundamental part of a machine language instruction. It specifies the operation that a computer’s central processing unit (CPU) should perform, such as addition, subtraction, or memory access.
b) Operating System: An operating system is software that manages and controls the hardware and software resources of a computer. It provides services like process management, file management, memory management, and user interface, allowing users and applications to interact with the computer’s hardware in a structured and efficient manner.
c) Kernel: The kernel is the core component of an operating system that manages hardware resources and provides essential services to other software components. It acts as an intermediary between user-level applications and the hardware, handling tasks like process scheduling, memory management, and device drivers.
d) Built-ins: Built-ins typically refer to functions or commands that are an integral part of a programming language or software system. They are readily available for use without the need for additional libraries or external dependencies.
e) Instruction Pointer: The instruction pointer (IP) is a register in a CPU that points to the memory address of the next instruction to be executed. It plays a crucial role in the CPU’s control flow and program execution.
f) MBR: The Master Boot Record (MBR) is a small, special boot sector located at the beginning of a storage device, such as a hard disk drive. It contains the bootloader code and the partition table, enabling the computer to boot into an operating system.
g) Program vs. Process vs. Processor:
Program: A program is a set of instructions and code written to perform a specific task. It exists as a file on storage and becomes a process when executed.
Process: A process is an executing instance of a program. It includes the program’s code, data, and resources, and it runs independently with its own memory space.
Processor: A processor is the central processing unit (CPU) of a computer. It executes instructions and manages data. Multiple processes can run on a single processor, and modern computers often have multiple processors or cores.
h) System Call: A system call is an interface provided by an operating system that allows user-level programs to request services from the kernel, such as file operations, process management, and network communication. System calls enable user programs to interact with hardware and privileged kernel resources.
i) Platform-free Program: A platform-free program is a piece of software designed to run on multiple platforms or operating systems without modification. These programs are typically written in a way that abstracts platform-specific details, making them portable and compatible with various environments. This may involve using cross-platform libraries or programming languages.