MOS versions

OS 1.10

Existance implied by existance of OS 1.20.

OS 1.20

Standard production MOS for BBC A/B.

OS A1.0

American OS 1.20

OS 1.21

Existance implied by existance of OS 1.23.

OS 1.22

Existance implied by existance of OS 1.23.

OS 2.00

Standard production MOS for BBC B+.

OS 2.10

Cambridge Workstation

OS 2.30

Standard production MOS for Reuters BBC B+. "OS R0.3"

MOS 3.00

Existance implied by existance of MOS 3.20.

MOS 3.10

Existance implied by existance of MOS 3.20.

MOS 3.20

Standard production MOS for BBC Master.

MOS 3.30

Existance implied by existance of MOS 3.50.

MOS 3.40

Existance implied by existance of MOS 3.50.

MOS 3.50

Optional upgrade for BBC Master.

MOS 3.5A

Tinsley

MOS 4.00

Standard production MOS for BBC Master ET.

MOS 5.00

Early production MOS for Master Compact.

MOS 5.10

Standard production MOS for Master Compact.