OS Building and Booting in Fundamentals of OS
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The document outlines the structure and operations of operating systems, including the need for OS, booting procedures, and debugging processes. It details the steps involved in building and booting an operating system from scratch, including configuring and compiling the OS. Additionally, it discusses performance tuning techniques and tools necessary for debugging and tracing system behavior.
![22CS301 - Operating Systems
1.9 Building and Booting OS
MODULE 1 -Computer Systems
Course Outcome:
Upon completion of the session, students shall have ability to
CO1 Identify the basic concepts and operations of operating systems. [U]](https://image.slidesharecdn.com/os-building-and-booting-240605030834-dc8d6427/85/OS-Building-and-Booting-in-Fundamentals-of-OS-3-320.jpg)
OS Building and Booting in Fundamentals of OS
- 1. 22CS301 - Operating Systems 22CS301 OPERATING SYSTEM MODULE 1 -Computer Systems
- 2. 22CS301 - Operating Systems Session Topic 1.1 Need for Operating Systems -Abstract view of OS 1.2 Computer Systems 1.3 OS Operations 1.4 Virtualization 1.5 Computing Environments 1.6 OS Services 1.7 OS Structures 1.8 System Calls 1.9 Building and Booting OS 1.10 Process 1.11 Threads 1.12 Multithreading Module 1- Introduction MODULE 1 -Computer Systems
- 3. 22CS301 - Operating Systems 1.9 Building and Booting OS MODULE 1 -Computer Systems Course Outcome: Upon completion of the session, students shall have ability to CO1 Identify the basic concepts and operations of operating systems. [U]
- 4. 22CS301 - Operating Systems Building and Booting an Operating System • Operating systems generally designed to run on a class of systems with variety of peripherals • Commonly, operating system already installed on purchased computer – But can build and install some other operating systems – If generating an operating system from scratch • Write the operating system source code • Configure the operating system for the system on which it will run • Compile the operating system • Install the operating system • Boot the computer and its new operating system
- 5. 22CS301 - Operating Systems • The operating system is loaded via a bootstrapping procedure, often known as booting. • The process of booting involves turning on a computer. • The memory of the CPU is empty when it is first turned on. • After loading the operating system into the main memory and turning on the computer, it is prepared to accept user commands. • The initial collection of tasks the computer carries out when turned on is known as the boot sequence. • The kernel is located, loaded into the main memory, and executed by the bootstrap loader. In some systems, the kernel is loaded after a straightforward bootstrap loader retrieves a more intricate boot program from the disk. • Restarting a computer is sometimes referred to as rebooting. MODULE 1 -Computer Systems Booting
- 6. 22CS301 - Operating Systems Step 1: BIOS is loaded Step 2: BIOS: Power on Self-Test • This test runs a preliminary examination of the computer's main memory, disk drives, input/output devices, etc. Moreover, the system emits a beep sound in case of any errors. Step 3: Loading of OS • The bootable sequence stored in the CMOS is read by BIOS following the successful completion of POST. Step 4: System Configuration Step 5: Loading System Utilities • In this step, system utilities like antivirus and volume control are loaded into the memory. Step 6: User Authentication MODULE 1 -Computer Systems Steps of Booting Process in Operating System
- 7. 22CS301 - Operating Systems Building and Booting Linux • Download Linux source code (http://www.kernel.org) • Configure kernel via “make menuconfig” • Compile the kernel using “make” – Produces vmlinuz, the kernel image – Compile kernel modules via “make modules” – Install kernel modules into vmlinuz via “make modules_install” – Install new kernel on the system via “make install”
- 8. 22CS301 - Operating Systems System Boot • When power initialized on system, execution starts at a fixed memory location • Operating system must be made available to hardware so hardware can start it – Small piece of code – bootstrap loader, BIOS, stored in ROM or EEPROM locates the kernel, loads it into memory, and starts it – Sometimes two-step process where boot block at fixed location loaded by ROM code, which loads bootstrap loader from disk – Modern systems replace BIOS with Unified Extensible Firmware Interface (UEFI) • Common bootstrap loader, GRUB, allows selection of kernel from multiple disks, versions, kernel options • Kernel loads and system is then running • Boot loaders frequently allow various boot states, such as single user mode
- 9. 22CS301 - Operating Systems Operating-System Debugging • Debugging is finding and fixing errors, or bugs • Also performance tuning • OS generate log files containing error information • Failure of an application can generate core dump file capturing memory of the process • Operating system failure can generate crash dump file containing kernel memory • Beyond crashes, performance tuning can optimize system performance – Sometimes using trace listings of activities, recorded for analysis – Profiling is periodic sampling of instruction pointer to look for statistical trends Kernighan’s Law: “Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it.”
- 10. 22CS301 - Operating Systems Performance Tuning • Improve performance by removing bottlenecks • OS must provide means of computing and displaying measures of system behavior • For example, “top” program or Windows Task Manager
- 11. 22CS301 - Operating Systems Tracing Collects data for a specific event, such as steps involved in a system call invocation Tools include • strace – trace system calls invoked by a process • gdb – source-level debugger • perf – collection of Linux performance tools • tcpdump – collects network packets
- 12. 22CS301 - Operating Systems BCC Debugging interactions between user-level and kernel code nearly impossible without toolset that understands both and an instrument their actions BCC (BPF Compiler Collection) is a rich toolkit providing tracing features for Linux • See also the original DTrace For example, disksnoop.py traces disk I/O activity Many other tools (next slide)
- 13. 22CS301 - Operating Systems Linux bcc/BPF Tracing Tools
- 14. 22CS301 - Operating Systems try MODULE 1 -Computer Systems The type of booting occurs where the computers hang or reach a state of no response
- 15. 22CS301 - Operating Systems MODULE 1 -Computer Systems Warm Booting
- 16. 22CS301 - Operating Systems MODULE 1 -Computer Systems What type of booting “when a computer starts up for the first time or when it is shut down, and the power button is pressed to restart the system”.
- 17. 22CS301 - Operating Systems MODULE 1 -Computer Systems Cold Booting