Difference between revisions of "Graduate Software"
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=== Structure of a utility ROM === | === Structure of a utility ROM === | ||
| + | Each ROM is 16KB and has the following structure: | ||
| + | |||
| + | {| | ||
| + | |- | ||
| + | | ''Offset (Hex)'' | ||
| + | | ''Count'' | ||
| + | | ''Description'' | ||
| + | |- | ||
| + | | &100 | ||
| + | | 256 | ||
| + | | Directory (note 1) | ||
| + | |- | ||
| + | | &200 | ||
| + | | &3e00 | ||
| + | | Data area for files. | ||
| + | |} | ||
| + | |||
| + | Each directory entry has the following structure: | ||
| + | {| | ||
| + | |- | ||
| + | | ''Offset (Hex)'' | ||
| + | | ''Count'' | ||
| + | | ''Description'' | ||
| + | |- | ||
| + | | 0 | ||
| + | | 8 | ||
| + | | Filename (note 2) | ||
| + | |- | ||
| + | | 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. | ||
[[Category:Operating System]][[Category:CP/M]] | [[Category:Operating System]][[Category:CP/M]] | ||
Revision as of 11:39, 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 |
| &100 | 256 | Directory (note 1) |
| &200 | &3e00 | Data area for files. |
Each directory entry has the following structure:
| Offset (Hex) | Count | Description |
| 0 | 8 | Filename (note 2) |
| 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.
