This page is a small collection of source code, information, and links related to general Operating Systems’ Development on the Web.

SOURCE CODE

Here is some source code, written by Andy McLaughlin, which might be useful to programmers who are developing OS- like products on the x86 platform.   Files ending with an “.s” extension are NASM- compatible (Intel syntax) Assembler code.

enableA20.s	This is a fairly versatile snippet of code for enabling the x86’s A20 address line.   It’s a little bit lengthy, but it seems to work more reliably than other examples I’ve tried.  Cut and paste it into one of your existing source files.
vesaModes.s	This piece of 16-bit code will query the VESA BIOS for a supported graphics mode number based on the desired parameters of resolution and colour depth.  Cut and paste it into one of your existing source files.

LINKS Here are some selected links to sites useful to OS developers (much of this is specific to PC- style hardware architectures).  Please email me about any broken links or erroneous descriptions.  Thanks. General Questions For an OS Designer So, why are you doing this anyway?  This should be required reading for anyone contemplating starting an OS project The OSDev.org wiki Almost everything you need to know about OS development The Operating Systems Resource Center Great collection of technical information and tutorials SigOps: Create Your Own Operating System This is a broadly focused site about OS theory Ralf Brown’s Interrupt List (also try this HTML Version) Don’t start any OS project on an x86 machine without getting this first. HelpPC WWW conversion (or download the actual HelpPC application) Likewise. sandpile.org — 80×86 index Lots of good information about x86 processors. NASM – The Netwide Assembler Project – FREE 80×86 assembler A GREAT little open- source assembler for x86 machines.   File systems Design and Implementation of the Second Extended File System The original EXT2 white paper The Second Extended File System Another EXT2 doc from a Linux site The Filesystems HOWTO Info about lots of different filesystems File System Info HPFS, FAT, NTFS info The Second Extended (EXT2) File System An EXT2 “book” by Dave Poirier.  Very good. EXT4 Disk Layout Very detailed info about the new features found in EXT4 The Extended-2 (EXT2) Filesystem Overview A white paper by Gadi Oxman.  A bit dated, but good as an alternative source of EXT2 information. UDF (DVD) filesystem DVD-ROM filesystem format specifications UDF (DVD) filesystem Good intoduction to UDF   File Formats Wotsit’s Format: The programmer’s file formats and data formats resource. This site is a godsend.  Information on file formats of almost any kind.   Look here before you go anywhere else. Standard Disk Format (Maverick) All about the format of the x86 Master Boot Sector DJGPP COFF Spec About the COFF object file format The Graphics File Format Page Info about lots of graphic file formats PCF Bitmap Font Files X11 (Linux, Unix) font file format   PC Hardware References Pentium(r)Processor – Manuals You need this if you’re going to do any coding in x86 Assembly language ATA-ATAPI.COM — ATA ATAPI IDE EIDE Fil’s FAQ-Link-In Corner: IDE Ref. ATA/ATAPI Errata Programming the PC’s IDE controller OSDev.org’s AHCI (native SATA) page SATA on Linux Programming the PC’s SATA controller VGA graphics Programming High-res high-speed VESA tutorial Game Programming and graphics programming 256-Color VGA Programming in C – Home Graphics and sound – The Hornet Archive Programming the PC’s video hardware The PS/2 Keyboard Interface Programming the PC keyboard PS/2 Mouse Interfacing Programming the PC mouse Serial Links using RS-232 and RS-485 Serial port programming information /pub/usenet/news.answers/pc-hardware-faq PC hardware Usenet FAQ   Networking The TCP/IP Guide Comprehensive, detailed book (readable online for free) about the low-level implementation of TCP/IP Beej’s Guide to Network Programming Excellent general guide to TCP/IP networking and user-space network programming, library functions, etc. The IP Protocol The IP networking protocol (you need to implement this before TCP, UDP, etc.) DNS Protocol Good overview of DNS from a MS TechNet page DNS (firewall.cx) Detailed breakdown of DNS queries and responses Choosing an Ethernet NIC Some Linux-related general info about network cards   Graphics Wikipedia’s JPEG page Calvin Hass’s JPEG decoding pages – Huffman coding – MCUs – Chroma subsampling – JPEGsnoop (dumps JPEG data) – Lossless rotation – Lossless rotation of partial MCUs Dr. Dobb’s JPEG-like image compression JPEG image decoding and the JFIF file format Wikipedia’s bicubic interpolation page Wikipedia’s bilinear filtering page Image resizing   Miscellaneous RFC 1321 – The MD5 Message-Digest Algorithm The MD5 hashing algorithm (for passwords, etc.) EFI: 64-bit System Design Documents and links describing EFI firmware, GPT partition tables, etc. from Microsoft