6502Em

6502Em will not run without at least one set of ROMs. The following versions of the OS are supported:

OS 1.2

This was the final release of the OS for the BBC Model B

files needed:

!6502Em.ROMs.OS1,2             The Operating System itself
!6502Em.ROMs.BASICII           The BBC BASIC interpreter

OS 3.2

This was the first release (of two) of the OS for the BBC Master

files needed:

!6502Em.ROMs.M128.OS3,2        The Operating System itself
!6502Em.ROMs.M128.Terminal     Terminal 1.20 ROM, plus more OS
!6502Em.ROMs.M128.View         View 3.0 ROM, plus a little OS
(!6502Em.ROMs.M128.ADFS1,50     ADFS, not currently loaded by emulator)
!6502Em.ROMs.M128.BASICIV84    The BBC BASIC interpreter
!6502Em.ROMs.M128.Edit1,00     Edit ROM (
!6502Em.ROMs.M128.ViewSheet    Viewsheet 1.0 ROM
!6502Em.ROMs.M128.DFS2,24      DFS ROM - provides *SRLOAD etc

OS 3.5

This was the second release (of two) of the OS for the BBC Master

files needed:

!6502Em.ROMs.M128.OS3,5        The Operating System itself
!6502Em.ROMs.M128.Terminal35   Terminal 1.20 ROM, plus more OS
!6502Em.ROMs.M128.ViewB3,3     View 3.3 ROM
(!6502Em.ROMs.M128.ADFS2,03     ADFS, not currently loaded by emulator)
!6502Em.ROMs.M128.BASIC4r32    The BBC BASIC interpreter
!6502Em.ROMs.M128.Edit1,50r    Edit ROM
!6502Em.ROMs.M128.ViewSh1,01   Viewsheet 1.01 ROM
!6502Em.ROMs.M128.DFS2,45      DFS ROM, plus a little OS

Some of the changes from 3.2:

• Startup message is "ACORN MOS" not "Acorn MOS"
• Sideways ROMs can now be automatically relocated over the tube (BASIC, Edit)
• Sideways RAM Utilities now in kernel
• ADFS *Format, *Verify and *Backup now in ROM (decoded by MOS)
• CLOSE#0 and EXT#= now work under DFS
• Larger range of step values available (*CONFIGURE FDRIVE)
• Support for international characters in filing system names
• Area move, ellipse and sound code is now in DFS ROM
• A few extra CMOS options
• The ROM between &FC00 AND &FF00 now contains code

OS 5.1

This was the only release of the OS for the Master Compact

files needed:

!6502Em.ROMs.Compact.OS5,1     The Operating System itself
!6502Em.ROMs.Compact.Utils     OS * Commands (including *SRLOAD)
!6502Em.ROMs.Compact.BASICIV86 The BBC BASIC interpreter
(!6502Em.ROMs.Compact.ADFS2,10  ADFS, not currently loaded by emulator)

OS 1.0

This was the only release of the OS for the Acorn Electron

files needed:

!6502Em.ROMs.Electron          The Operating System itself
!6502Em.ROMs.BASICII           The BBC BASIC interpreter

Historical Note

OS 2.x was for the BBC B+

OS 3.5 was the second release for the Master 128

OS 4.x was for the Master ET (Econet Terminal)

Previous releases for the original BBC were 0.10 and 1.00

The Electron's OS was, confusingly, also 1.00