User`s guide

The Error Code definitions for register A are shown in Table 2-7.

Table 2-7. Register A BDOS Error Codes

Code Meaning

00 Function successful

255 Physical error : refer to register H

01 Reading unwritten data or no available directory space (Write

Sequential)

02 No available data block

03 Cannot close current extent

04 Seek to unwritten extent

05 No available directory space

06 Random record number out of range

09 Invalid FCB (previous BDOS close call returned an error code

and invalidated the FCB)

10 Media Changed (A media change was detected on the FCB's

drive after the FCB was opened)

For BDOS read or write functions, the file system also sets register H when the

returned Error Code is a value other than zero or 255. In this case, register H

contains the number of 128-byte records successfully read or written before the error

was encountered. Note that register H can contain only a nonzero value if the calling

program has set the BDOS Multi-Sector Count to a value other than one; otherwise

set to zero. If the Error Code equals 255, register H contains a physical error code

(see Table 2-11).

2-31

2.3 BDOS File System CP/M 3 Programmer's Guide