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The Implementation of the ULIX Literate Operating System

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Subscribe ULIX: Literate Unix

A diary documenting the implementation of ULIX-i386

Welcome to the ULIX blog.

Ulix (Literate Unix) is a Unix-like operating system developed at University of Erlangen-Nürnberg. I use D. E. Knuth's concept of Literate Programming for the implementation and documentation. The goal was a fully working system which can be used in operating system courses to show students how OS concepts (such as paging and scheduling) can be implemented. Literate programs are very accessible because they can be read like a book; the order of presentation is not enforced by program logic or compiler restrictions, but instead is guided by the implementer's creative process.

Ulix is written in C and assembler for the Intel architecture. The literate programming part is handled by noweb.

On this page I document my progress with the implementation.


Navigation: 2015 | 2014 | 2013 | 2012 | 2011


Bug fix :) (19.05.2012)


I found a bug in memory management that came into being after including code for creating new address spaces: When there is more than one address space, we have (identical) copies of the page directory's mapping for c0000000..ffffffff -- so when an entry in that area is modifed (i.e. a new page table is created and linked from that page directory) it must also be modified in all existing copies... Took me quite a while to find it, but now the code is OK :) Memory setup works for processes (as long as no more than 4 MB are requested; can be fixed easily), so the system is ready for process creation.

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