#FILE: $RCSfile: os9formt.txt $ #DESC: OS9 Disk and File formats #REV: $Revision: 1.1 $ #DATE: 06/04/94 #AUTHOR: Graham E.Kinns #DISCLAIMER: All information provided as is etc. #ARCHIVE: This file is part of the DRGNINFO collection of Dragon info files #CONTACT: Comments, bugs, revisions, suggestions to Dragon@grempc.demon.co.uk #HISTORY: 1.0 22/03/94 - Initial version #RCSID: $Id: os9formt.txt 1.1 1995/08/18 14:33:17 Graham Exp $ #SOURCE: Dragon OS9 System Programmer's Manual + additional 0. Introduction ================ This file represents all I've amassed about the OS9 disk and file formats, particulartly OS9 level 1 as released by Dragon Data Ltd, UK for the Dragon computer in 1983 shortly before their demise. Incidently, it is believed Microware never received any license royalties whatsoever. Having never run OS9, I may be missing a few things which are obvious to the experienced user. All words are stored in Motorola hi-order format. 1. Known disk formats ====================== 2. Sector organization ======================= 3. Identification Sector ========================= Identification Sector resides on LSN 0 and contains the Disk Descriptor: Os9 ref Byte Length Description offset (bytes) DD.TOT 0x00 3 Total number of sectors on media DD.TKS 0x03 1 Number of tracks DD.MAP 0x04 2 Number of bytes in allocation map DD.BIT 0x06 2 Number of sectors per cluster DD.DIR 0x08 3 Starting sector of root directory DD.OWN 0x0b 2 Owner's user number DD.ATT 0x0c 1 Disk attributes (to be clarified) bit 7: D - Directory bit 6: S - Shared bit 5: PE - Public Execute bit 4: PW - Public Write bit 3: PR - Public Read bit 2: E - Execute bit 1: W - Write bit 0: R - Read DD.DSK 0x0e 2 Disk identification (for internal use) DD.FMT 0x10 1 Disk format: density, number of sides bit 7: bit 6: bit 5: bit 4: bit 3: bit 2: bit 1: bit 0: DD.SPT 0x11 2 Number of sectors per track DD.RES 0x13 2 Reserved for future use (under Level 1) DD.BT 0x15 3 Starting sector of bootstrap file DD.BSZ 0x18 2 Size of bootstrap file (in bytes) DD.DAT 0x1a 5 Time of creation: Y : M : D : H : M DD.NAM 0x1f 32 Volume name: last char has sign bit set 4. Allocation Map ================== 5. File / Directory storage ============================ The first sector of every file contains a file descriptor, which contains the logical and physical description of the file. The table below describes the contents of the descriptor. Os9 ref Byte Length Description offset (bytes) FD.ATT 0x00 1 File Attributes: D S PE PW PR E W R bit 7: D - Directory bit 6: S - Shared bit 5: PE - Public Execute bit 4: PW - Public Write bit 3: PR - Public Read bit 2: E - Execute bit 1: W - Write bit 0: R - Read FD.OWN 0x01 2 Owner's User ID FD.DAT 0x03 5 Date Last Modified Y : M : D : H : M FD.LNK 0x08 1 Link Count FD.SIZ 0x09 4 File Size (number of bytes) FD.DCR 0x0d 3 Date Created: Y : M : D FD.SEG 0x10 240 Segment List: see below ------------------------------------------------------------------------------ 99. Acknowledgements ===================== David J. Linsley ( djl102@tower.york.ac.uk ) for the information from the Dragon 6809/OS9 Lev 1 System Programmer's Manual All trademarks, servicemarks etc. are acknowledged