Data Access and Storage

In this module, we will learn about the two key abstractions that operating systems provide to processes in order to organize and represent data. First, we will study the basics of memory management, and dynamic allocation. Next we will study the fundamental concepts and abstractions that make up a file system, and explore how these abstractions are realised in both the high-level C standard I/O library, and in the low-level POSIX system call interfaces. And, we will compare and contrast these abstractions from a systems programming perspective, while investigating the connections between them. By the end of this module, students will be able to work with allocated memory, understand the basic concepts and abstractions of file systems, be able to use the facilities provided by both the C library and POSIX system calls to perform file system tasks, and finally be able to demonstrate the relationship between the standard library and the underlying system calls that it is built on top of.

Module Learning Outcomes

After successful completion of this module, you will

Understand and explain the fundamental abstractions of a file system
- Structure and organization
- File access, permissions, and representation
- C streams concepts
- POSIX-specific concepts
Write C programs that use the C standard I/O library features to,
- Manage and work with dynamically allocated memory
- Open, read from, write to, and close files
- Select appropriate file buffering modes
- Use file positioning to access structured data
- Handle errors and end-of-file conditions
Write C programs that use POSIX system calls to do all of the above, and,
- Appropriately use blocking and non-blocking I/O
- Use polling to manage simultaneous input streams
- Inspect and manipulate file meta-information
- Navigate and manipulate file system structure
- Manipulate files of different types
Write an implementation of the C standard I/O library using POSIX system calls