Graduate Software

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Graduate software provided a version of CP/M+ on ROM.

Additional 'utility' roms contained CP/M programs installed on a ROM.

Structure of a utility ROM

Each ROM is 16KB and has the following structure:

Offset (Hex) Count Description
0 48 Description of ROM (note 1)
&100 256 Directory (note 2)
&200 &3e00 Data area for files.

Each directory entry has the following structure:

Offset (Hex) Count Description
0 8 Filename (note 3)
8 1  ? (unknown &20)
9 2 address in ROM for start of data for file (note 3)
11 2 length in bytes of file
14 2 (unknown) &feff

Notes

1. Up to 16 files can be defined. Each file takes 1 entry. Unused entries are filled with &FF.

2. Filename is in upper case, 8 characters long, padded with spaces. '.COM' extension is assumed when accessed.

3. ROM starts at &c000. Therefore &c200 is the start of the first file.