Table of Contents
Advertisement
Basic Disk Operating System (BDOS) Functions
The "SELECT" error is also issued as the result of an error condition returned to the
BDOS from the BIOS module. The BDOS makes a BIOS disk select call prior to
issuing any BIOS read or write to a particular drive.
If
the selected drive is not
supported in the BIOS module, it returns an error code to the BDOS resulting in this
error message. CP/M-86 terminates the currently running program and returns to
the command level of the CCP following any input from the console.
The "R/O" message occurs when the BDOS receives a command to write to a drive
that is in read/only status. Drives may be placed in read/only status explicitly by a
STAT command or BDOS function call, or implicitly if the BDOS detects that a
diskette medium has been changed and a warm start has not been performed. The
ability to detect changed media is optionally included in the BIOS, and exists only if
a checksum vector is included for the selected drive. When any character is pressed
on the keyboard, the transient program is aborted and control returns to the CCP.
RESET DISK SYSTEM
ENTRY
RETURN
CL:
ODH
FUNCTION 13
RESET DISK SYSTEM
The Reset Disk function programmatically restores the file system to a reset state
where all drives are set to read/write (see functions 28 and 29) and Drive A is
selected as the default. This function can be used, for example, by an application
program which requires diskette changes during operation. Function 37 (Reset
Drive) can also be used for this purpose.
4-13
Advertisement
Table of Contents
