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Michael Piepers homepage | ||||
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BeOS Programs | ||||
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PalmBeach | ||||
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PSION Link Protocol description | ||||
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RFSV Protocol description | ||||
The command FWRITE used around data into a file opened before to write. It must; the same File handle to be used, as with the instruction FOPEN one returned the delivery.
Since with FWRITE very gross;e quantities of data will transfer can, it is to be made certain that; a command of several Frames to consist can! In PLP protocol the counter is inserted for it which indicates descending the number of blocks still which can be expected (inclusive of the own).
It is to be noted that; all values, which are more greater than 8 bits in reverse order will transfer. The LOW byte sent as the first over the line and only then follows the HIGH byte!
The instruction FWRITE is as a consequence built into the PLP:
| Header | PLP | RFSV FWRITE | Footer | CRC | |||
|---|---|---|---|---|---|---|---|
| 16 10 02 | 32 03 02 01 | Command 0a 00 |
Size 12 34 |
File handle 01 00 |
Data 01 02 03 04 05... |
10 03 | 12 34 |
If the instruction FWRITE is divided on several Frames, then in the log by the counter one marks. This is directly before the RFSV log and counts down. The following example shows two blocks, which show an FWRITE instruction with 512 byte data. The counter is yellow marked.
| Header | PLP | Counter | RFSV FWRITE part 1 | Footer | CRC | |||
|---|---|---|---|---|---|---|---|---|
| 16 10 02 | 32 03 02 | 02 | Command 0a 00 |
Size 02 02 |
File handle 01 00 |
Data 01 02 03 04 05... |
10 03 | 12 34 |
| Header | PLP | Counter | RFSV FWRITE part 2 | Footer | CRC |
|---|---|---|---|---|---|
| 16 10 02 | 33 03 02 | 01 | Data 06 07 08 09 0a... |
10 03 | 12 34 |
With the implementation for that BeOS this counter is however already analyzed in the basic program, so that; the blocks always compiled and the ADD on to be supplied.
A valid response takes place with the command RESPONSE and returns the delivery an error code.
| Header | PLP | RFSV RESPONSE | Footer | CRC | ||
|---|---|---|---|---|---|---|
| 16 10 02 | 33 02 03 01 | Command 2a 00 |
Size 02 00 |
Result 00 00 |
10 03 | 12 34 |
The command FWRITE consists of 4 information units. These have the following meanings:
| Length in byte | possible values | Meaning | |
|---|---|---|---|
| Command | 2 byte | 00 0a (fixed) | The command identifier has always the same value! |
| Size | 2 byte | variable | The length of the complete instruction is indicated. If this is divided into two frames, then the specification corresponds to the length of both frames. |
| File handle | 2 byte | variable | It is too transferred to the File handle, in whose file is to be written. |
| Data | variable | variable | Here follow the data, which are to be written. The number is indicated in the field Size. |
The command FWRITE is answered with RESPONSE. This returns the delivery an error code as result. If 00 00 is returned the delivery, then no error occurred.
| Length in byte | possible values | Meaning | ||||
|---|---|---|---|---|---|---|
| Command | 2 byte | 00 2a (fixed) | The command identifier has always the same value! | |||
| Size | 2 byte | 00 02 (fixed) | Always 2 additional byte are supplied! | |||
| Result | 2 byte | variable | The result can obtain the following values:
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|
Michael Piepers homepage | ||||
|
BeOS Programs | ||||
|
PalmBeach | ||||
|
PSION Link Protocol description | ||||
|
RFSV Protocol description | ||||