wiki:Architecture

Version 3 (modified by soujak, 18 years ago) (diff)

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Project architecture

1. File system organization

The distribution is subdivided in several folders in order to efficiently organize files and logically separate them into different sections. Kaya is a layered OS, so each Phase has been confined in a sub-distribution own hierarchy, in order to ease interchanges between different implementation of the same layer and to underline that opportunity. In addition to this, each Phase has the classic structure

  • phaseN/
    • src/: sources folder containing Phase N source code and a test programs;
    • obj/: Phase N objects files;
    • include/: library headers of Phase N;
  • include/: system common headers: constants and macro definitions (const.h), types and data structures definitions (types.h);
  • dev/: uMPS virtual devices;
  • doc/: documentation root containing various developers informations about project internals and development process.

2. Source modules organization

2.1. Phase 1

Following the evident logical division between two entities that we had to instantiate - processes and semaphores -, we opted for a two-modules subdivision:

  • pcb.c: collects primitive functions for PCBs initialization/ allocation/ deallocation, process queue/ tree maintenance;
  • st.c: collects primitive functions for SD tree initialization and PCB enqueueing to/dequeueing from semaphores.

2.2. Phase 2

Nucleus modular division reflects main objectives of the operating system: hardware interface, process alternation, low-level synchronization primitives and exception handling routines. Let's see such division in details:

  • initial.c implements main() and exports the nucleus’s global variables (e.g. process count, device descriptors, etc.);
  • interrupts.c implements the device interrupt exception handler. Processes all the device interrupts, including Interval Timer interrupts, converting device interrupts into V operations on the appropriate semaphores;
  • exception.c implements the TLB program trap and syscall/breakpoint exception handlers;
  • dispatcher.c implements Kaya’s process dispatcher and deadlock detector;
  • scheduler.c implements Kaya’s process configurable scheduler;
  • tools.c implements some kernel utilties and debugging tools.