Atom Lite+

The AL+ is an optimized and quick 8-bit version of the Atom IDE interface with a real-time-clock chip and a double CF-IDE adapter. It could be placed into one or both disk-drive slots of the Coupé. For the AL+ is available a special ROM with changed bootstrap code and some redefined keys (F7 and F8 for DIR, CNTRL+Z for RECORD). This BootROM v2.2 supports booting from any of the four possible (bootable formatted) CF cards. The forced boot is done by holding the keys 1 to 4 during the start-up of the computer (or 0 for no boot).

BDOS

The AL´s operating system, B-DOS, is based on the improved SAMDOS. CF interfaces under the B-DOS act as virtual second disk drives. The whole CF card is splitted into chunks of 819200 bytes, called ´records´, representing Coupé´s disk images (even ZX Spectrum´s Disciple and PlusD formats, DSK and MGT images, are readable).

The B-DOS handles 8GB from the space of the CF card. This limitation may upset anyone with more than 10000 floppy images to store.

The B-DOS features some MasterDOS capabilities: the speed, the ask option for multiple operations and the date stamping. B-DOS has not implemented directories yet, although you could name records systematically (e.g. GAM:, DEM:, MAG:, TXT:, PIC:, SRC: etc.) and then make the list with the command RECORD ,"GAM:*". Every record can be named with a 16 character name (filenames take 10 chars only).

The full command set and the detailed B-DOS description you can find in the documentation written by the author of the Atom Lite+ and the B-DOS v1.5a, Edwin Blink.

BDOS Versions

Please note the different versions of the B-DOS are used for the following Coupé´s storage devices:

version 1.5a for Atom Lite(+)
version 1.5t is the v1.5a patched for the Trinity SD slot
versions 1.6 and 1.7 support ATAPI and 16-bit IDE devices (with the classic Atom only)

Software

The vast majority of old good Coupé´s programs should run on the AL+ without any modification. However a small amount of MasterDOS and MasterBASIC programs could need some changes.

Patches exist for these games with a direct disc-access:

Sphera
Lemmings
Bulgulators (Mr Pac)
Batz ´n´ Balls (Arkanoid clone)
Prince of Persia
Momentum
Lemmings

Worth to mention are special versions of the SAM Paint and the the Solar Flare´s Mod Player.

Programming Tips

Many tips and hints can be found in the documentation.

The formatted CF card starts with the boot sector (always a single sector), then the records list follows (each record list entry is the 16-byte text label, so there are 32 entries per sector). The next space on the disk is broken into 1600-sector-long blocks (records). In case the end space has at least 40 sectors, a short record is created, otherwise it is ignored.

Record list size (in sectors) = (all sectors / 1600 + 32) / 32
Selected record(disk drive = 0) = (PEEK DVAR 7 = 2) * DPEEK DVAR 25