Technical information for the user Firmware | Amstrad DDI-1 specs

CHAPTER 5

Technical information for the user – Firmware

This chapter assumes prior knowledge of the CPC464 firmware.

Some knowledge of the fundamentals of CP/M is also assumed. This chapter does not however attempt to discuss the facilities available in the CP/M environment. Complete information concerning CP/M, the CPC464 CP/M environment and the technical specification of the BIOS is contained in SOFT159 A Guide to CP/M. The Complete Firmware Specification of the Amstrad DDI-1 is contained in SOFT 158A, available as an Appendix to the Concise Firmware Specification SOFT158.

5.0 Introduction

AMSDOS is a disc operating system for the AMSTRAD CPC464 fitted with the DDI- 1 floppy disc interface. AMSDOS enables BASIC programs to access disc files in a similar manner to cassette files, indeed existing programs which currently use the cassette should be able to use disc files with little, or no, modification. The main source of incompatability will be file names in that, for AMSDOS, files names must conform to CP/M standards whereas cassette file names are far less restricted.

AMSDOS has been designed to complement CP/M, not to compete with it. They share the same file structure and can read and write each other's files. AMSDOS resides in the same ROM as the CP/M BIOS.

AMSDOS switches the cassette input and output streams (#9) to and from disc. Thus all the facilities available on cassette become available on disc. In addition displaying the disc directory, erasing disc files, renaming disc files, and selecting the default drive and user are also facilitated.

These facilities are implemented either by intercepting the cassette firmware calls or by external commands.

5.1 Headers

Cassette files are subdivided into 2k blocks, each of which is preceded by a header. CP/M files do not have headers. AMSDOS files may, or may not, have a header depending on the contents of the file. This will not cause problems for programs written in BASIC but is an important difference between cassette and disc files. This could perhaps be exploited for a protection scheme.

Chapter 5.

AMSTRAD Disc Drive & Interface DDI-1 Manual

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Amstrad DDI-1 manual Technical information for the user Firmware, Headers

Contents

Page Amstrad Disc Drive & Interface DDI-1 Amstrad Contents Contents Page Connecting the Mains Lead Foundations 1 Setting Up Connecting the DDI-1 to the Computer Computer Interface Unit Main Disc Drive Drive a Computer Write Protection Foundations 2 About Discs Open Closed When Your Disc Is Eject Button Indicator Lamp ROLCAVE. not found Drive a disc missing Retry, Ignore or Cancel?Foundations Loading Software/Games Run rolcave Type mismatch Bad commandSyntax error Drive a read fail Retry, Ignore or Cancel? Foundations Introducing Amsdos and CP/M Tape.in Drive B disc missing Retry, Ignore or CancelLoad filename Disc Cpm First Steps Using The CP/M DiscStoring Data Onto Disc CLS? Saving a Program in Memory onto Disc Back to AmsdosBeware EXAMPLE.BAS CatalogLoading From Disc Copying Programs From Disc to Cassette Copying Programs From Disc to DiscCopying Programs From Cassette to Disc Copying Using Disccopy Copying Using the CP/M System Disc Do you want to copy another disc Y/N Copying Using CopydiscCopying started Reading track 0 to Writing track 0 to Chkdisc Checking DiscsAborting Discchk Installation Amstrad Disc Drive & Interface DDI-1 Manual Making Working Discs Backup Master Disc DISCCOPY.COM Working SYSTEM/UTILITY discBasic only disc Turnkey Amstrad Basic discs Creating a Turnkey CP/M System disc Turnkey Basic using disc suppliedTurnkey CP/M Discs Turnkey Basic onto your Working disc Ambiguous filename Confirm individual files Y/N ? Configuring a CP/M ProgramConfiguring the Output from the package Payroll Configuring the Input to the packageStarting a Turnkey CP/M Package Autostarting a Turnkey CP/M Package Introduction Amsdos Primer Construction of Filenames Disc DirectoryAmsdos filenames and filetypes Save PROG.BAS a Save Bprog .BAS Amsdos headersFilenames on two drives BERT.BAS FRED1.BAS FRED2.BAS FRED3.BAK FRED3.BAS FINISH.BAS Examples of Using Amsdos Commands in a programWild cards Saving variables and performing a Screen Dump Closeout Neat Wend Closein Reference guide to Amsdos commandsPre-empting a Garbage Collection While not EOF CAT Summary of Basic commandsSummary of Amsdos external commands Save OPENOUT, Print #9, Write #9, List #9, Closeout DISC.IN CPMDIR Disc TAPE.IN ERAREN Tape Ascii files File Copying proceduresCopying Files Amsdos files with headers File has a header Amstrad Reference guide to Amsdos Error Messages Drive Drive write fail Drive Drive disc missingDrive Drive disc is write protected Drive Drive read fail CP/M system tracks CP/M PrimerOperating with CP/M Logging in a disc Configuration SectorConsole control codes ERA command Direct Console CommandsSwitching default drives DIR command Peripheral Management Transient commandsREN command Type command Cassette files File and disc copyingSingle file copying Whole disc copiers and checkers Stat System Management Is this correct Y/N SetupDo you want to update your system disc Y/N Stat SECRET.BAS $DIR Format D Format I Format Disc GenerationAmsdos Format Sysgen BootgenAdvanced programming Movcpm Amstrad Disc Drive & Interface DDI-1 Manual Introduction to Logo What is Logo Getting Started Dr. Logo To squareanysize side repeat 4 fd side rt 90 end Procedures with parametersRepeat 4 fd 60 rt To square Repeat 4 fd 60 rt 90 end To triangle Repeat 3 fd edge rt 120 end Using Variables to remember valuesEditing programs and procedures Cs squareanysize 100 rt 45 squareanysize Summary of Dr. Logo primitives Operating hints Count Word and List ProcessingAscii Char List EmptypFirst Fput Arithmetic Operations Logical Operations ?= Logo Logo Not Variables Procedures Show EditingText Screen Setsplit Dot CleanGraphic Screen Type Window PalSetpal Wrap Turtle Graphics Setpc Seth Nodes Workspace ManagementSetpos Ern Plist RecycleGlist Gprop KEYBOARD, Joystick buttonp Disc Files DirLoad Save ?key Paddle?paddle 0 ?make key rc Release SoundEnv Ent Stop LabelRepeat Run Throw ErrorCatch Pause System Properties Headers Technical information for the user Firmware Store requirements Changing Discs Amsdos messages Error MessagesBios messages Failed to load boot sector Common to ALL Formats Disc Organisation Return Parameters Jump Block Interception by AmsdosJump Block Re-Interception by the User 137 #BC9B Intercepted Firmware Calls132 #BC8C 133 #BC8F 134 #BC92 135 #BC95 #BC98 Page Appendix Glossary of Terms CP/M Dr.Logo Primitives TPA Amstrad Disc Drive & Interface DDI-1 Manual Appendix Term Limitations of Remedies Amstrad Disc Drive & Interface DDI-1 Manual Appendix Index ERA Setpos