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TR-DOS filesystem: Difference between revisions
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→File descriptor format
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Note2: start line for basic programs is not saved in header file, indeed, it is stored directly at the end of file: after end of basic program (symbol #80), could be placed token #AA followed by little-endian word that reflects start line. | Note2: start line for basic programs is not saved in header file, indeed, it is stored directly at the end of file: after end of basic program (symbol #80), could be placed token #AA followed by little-endian word that reflects start line. | ||
===Example file descriptors=== | |||
====BASIC==== | |||
{| class=wikitable | |||
|- | |||
! | Offset (dec) | |||
! | Offest (hex) | |||
! | Bytes | |||
! | Content | |||
! | Description | |||
|- | |||
| 0-7 | |||
| 00-07 | |||
| 62 61 73 69 63 20 20 20 | |||
| "basic " | |||
| Filename | |||
|- | |||
| 8 | |||
| 08 | |||
| 43 | |||
| "B" (Basic) | |||
| File type | |||
|- | |||
| 9-10 | |||
| 09-0A | |||
| EF 01 | |||
| 495 bytes | |||
| File size including variables area minus area at the end containing the line number. | |||
|- | |||
| 11-12 | |||
| 0a-0b | |||
| 68 01 | |||
| 360 bytes | |||
| Pointer to the start of the variables area in the file. | |||
|- | |||
| 13 | |||
| 0C | |||
| 08 | |||
| 8 sectors long | |||
| Number of sectors the file uses | |||
|- | |||
| 14 | |||
| 0D | |||
| 02 | |||
| Start sector 2 | |||
| Sector the file starts from (Note, sectors number from 0 regardless of the actual disk layout) | |||
|- | |||
| 15 | |||
| 0E | |||
| 01 | |||
| Start logical track 1 | |||
| Logical Track the file starts from. (Note, the tracks are encoded as CH, so for DS drives, track 0=C0H0, 1=C0H1, 2=C1H0, ect) | |||
|} | |||
== File types == | == File types == | ||