Difference between revisions of "Graduate Software"
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(→Structure of a utility ROM) |
(→Structure of a utility ROM) |
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| Line 21: | Line 21: | ||
| &30 | | &30 | ||
| 208 | | 208 | ||
| − | | Loading code (note | + | | Loading code (note 2) |
|- | |- | ||
| &100 | | &100 | ||
| 256 | | 256 | ||
| − | | Directory (note | + | | Directory (note 3) |
|- | |- | ||
| &200 | | &200 | ||
| Line 41: | Line 41: | ||
| 0 | | 0 | ||
| 8 | | 8 | ||
| − | | Filename (note | + | | Filename (note 4) |
|- | |- | ||
| 8 | | 8 | ||
Revision as of 10:46, 28 April 2018
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) |
| &30 | 208 | Loading code (note 2) |
| &100 | 256 | Directory (note 3) |
| &200 | &3e00 | Data area for files. |
Each directory entry has the following structure:
| Offset (Hex) | Count | Description |
| 0 | 8 | Filename (note 4) |
| 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. Utility ROM 1 has this description: "Graduate (C)1988 CP/M Accessory Rom 1\r\n$VER 2.30 "
2. Up to 16 files can be defined. Each file takes 1 entry. Unused entries are filled with &FF.
3. Filename is in upper case, 8 characters long, padded with spaces. '.COM' extension is assumed when accessed.
4. ROM starts at &c000. Therefore &c200 is the start of the first file.
