ZDSFS: Difference between revisions

 

To find the sequence of format 1 entries the OS has to read 0, 0, 3. Place the first 20 bytes into a buffer then obtain the location of the format 1 DSCBs:

void GetCHRFromVTOC(void *buffer) {

uint16_t cyl, head;

return;

}

 

== Format 1 DSCB ==

The entries are ordered in a chain-like structure, where a formatId=0 entry denotes the end of said chain.

 

// NOTE: This code assumes EBCDIC is being used

void CheckDSCB(struct DSCB1 *dscb, const char *name) {

}

}

 

Finding the files is just a matter of reading records until reaching the end of the head, then incrementing heads and after reading the last head in the cylinder, incrementing cylinders. This also has to be done for reading files.

 

This is mostly specific to DASD devices but it's provided for clarity.

// NOTE: This code assumes EBCDIC is being used

void FindFile(const char *name) {

}

}

 

== See also ==

 

[[Category:S390]]