Chapter 1: Introduction - About the BBC Microcomputer, its memory map, and the scope of its operating system

Chapter 2: Memory Layout and Constants - The memory layout and constants

Chapter 3: Memory Mapped IO - Register locations for memory-mapped hardware

Chapter 4: Character definitions and VDU tables - Character definitions; Boot message; VDU tables - 1216 bytes (7.4%)

Chapter 5: VDU and OSWORD routines - VDU 0-6, 8-31, 127. OSWORD 9, 11, 12; VDUCHR entry point; Swap cursor variables; Check text or graphics cursor active; Hardware scrolling; Scroll in paged mode - 1629 bytes (9.9%)

Chapter 6: Changing MODEs - MODE change code; OSWORD 10; Clear screen - 475 bytes (2.8%)

Chapter 7: Graphics cursor and soft character definitions - OSBYTE 20; Cursor editing mode; Software scroll up/downwards; Exchange four VDU variables; Plot character at graphics cursor; Graphics cursor handling; MODE 7 character conversion; Setup soft character definitions - 872 bytes (5.3%)

Chapter 8: PLOT - OSBYTE 134; OSWORD 13; PLOT routine; Checking graphics cursor bounds; Coordinate conversion; PLOT line; Move graphics cursor; Copy VDU variables; PLOT lateral fill; PLOT fill triangle - 1890 bytes (11.5%)

Chapter 9: Cursor editing mode - OSBYTE 132, 133, 135; Cursor editing mode routines - 382 bytes (2.3%)

Chapter 10: Resets - OSBYTE 142; Default vector table; Default MOS variables table; Reset entry point - 732 bytes (4.4%)

Chapter 11: Interrupt processing - OSBYTE 17; IRQ entry point; BRK handler; IRQ1, IRQ2 handlers; Display string - 681 bytes (4.1%)

Chapter 12: Command Line Interpreter (star commands) - OSBYTE 127, 139; OSRDCH entry point; OSCLI Handler; Table of star commands; *BASIC; Reading hex values from strings; Copyright string (backwards) - 479 bytes (2.9%)

Chapter 13: Writing characters; printer; buffers - OSBYTE 123, 156; OSWRCH entry point; Econet / User printer routines; Flush buffers; Count or purge buffer (CNPV); Append to buffer - 362 bytes (2.2%)

Chapter 14: Star commands - *LOAD; *SAVE; *SPOOL; *KEY; *FX; OSBYTE 119, 138, 145, 152, 153; Clear OSFILE address; Tables of buffer addresses; EVENT entry point; Remove from buffer (REMV); Insert into buffer (INSV) - 933 bytes (5.6%)

Chapter 15: OSBYTE and OSWORD - VDU 7; OSBYTE 0-14, 16, 18, 19, 117, 118, 124-126, 128-130, 136, 137, 144, 147, 149, 151, 154, 155, 160, 247; OSWORD 0-8; OSBYTE entry point; OSWORD entry point; *LINE; *CODE; Serial baud rate / sound buffer table; GSINIT; GSREAD; Keyboard handling routines - 1360 bytes (8.3%)

Chapter 16: Sound and Speech - OSBYTE 158, 159; Sound and speech interrupt processing; ROM/PHROM read byte - 983 bytes (5.9%)

Chapter 17: Keyboard processing - OSBYTE 15, 21, 120-122, 131; Keyboard processing, translation table, scanning code; KEYV entry point; Speech table; *HELP - 603 bytes (3.6%)

Chapter 18: Tape and ROM Filing systems - OSBYTE 140, 141, 143; OSARGS entry; OSFILE entry; OSFIND entry; OSBGET entry; OSBPUT entry; File system vector table; FSC entry point; Setup tape options; Load and save file; Copy filename; *RUN; *CAT; *OPT; Search for block; Open a file; Save a block to tape - 1107 bytes (6.7%)

Chapter 19: Low Level Tape Operations - Update ACIA; Check EOF; Search for file; Spool or Exec file; Load and save block; Load block header; Load and save byte; Update CRC - 801 bytes (4.8%)

Chapter 20: Filing System Messaging and Error Reporting - Print progress; Prompt to record on tape; Print four byte hex; Check for ESCAPE during tape operations; Load block from tape; Print following message; Data? File? Block? error messages - 575 bytes (3.5%)

Chapter 21: More Low Level Tape Operations - Setup, Claim, and Reset ACIA; Cancel tape operation; Activate / deactivate RTS; Zero checksum; Copy filename; Motor on/off; Check file is open; Send data to second processor; Setup for cassette write - 280 bytes (1.7%)

Chapter 22: Credits - Credits string - 768 bytes (4.6%)

Chapter 23: Extended vectors - Extended vector entry points table; Extended vector handler - 167 bytes (1%)

Chapter 24: OS entry points; Tube; FRED; JIM; SHEILA - OSBYTE 146, 148, 150, 157; OS Entry points and 6502 Vectors (NMI, Reset, IRQ); Chapter 25: Appendix; Circuit diagrams in vector format; Chapter 26: Index; Index of MOS features as they are seen by user programs; - 89 bytes (0.5%)

Chapter 25: Appendix - Circuit diagrams in vector format

Index - Index of MOS features as they are seen by user programs