System information

1.8 Operation of CP/M on the MDS
This section gives operating procedures for using CP/M on the Intel MDS microcomputer
development system. Basic knowledge of the MDS hardware and software systems is assumed.
CP/M is initiated in essentially the same manner as the Intel ISIS operating system. The disk
drives are labeled 0 through 3 on the MDS, corresponding to CP/M drives A through D,
respectively. The CP/M system disk is inserted into drive 0, and the BOOT and RESET switches
are pressed in sequence. The interrupt 2 light should go on at this point. The space bar is then
pressed on the system console, and the light should go out. If it does not, the user should check
connections and baud rates. The BOOT switch is turned off, and the CP/M sign-on message
should appear at the selected console device, followed by the A> system prompt. You can then
issue the various resident and transient commands.
The CP/M system can be restarted (warm start) at any time by pushing the INT 0 switch on the
front panel. The built-in Intel ROM monitor can be initiated by pushing the INT 7 switch, which
generates an RST 7, except when operating under DDT, in which case the DDT program gets
control instead.
Diskettes can be removed from the drives at any time, and the system can be shut down during
operation without affecting data integrity. Do not remove a disk and replace it with another
without rebooting the system (cold or warm start) unless the inserted disk is Read-Only.
As a result of hardware hang-ups or malfunctions, CP/M might print the following message:
BDDS ERR ON d: BAD SECTOR
where d is the drive that has a permanent error. This error can occur when drive doors are opened
and closed randomly, followed by disk operations, or can be caused by a disk, drive, or controller
failure. You can optionally elect to ignore the error by pressing a single return at the console. The
error might produce a bad data record, requiring reinitialization of up to 128 bytes of data. You
can reboot the CP/M system and try the operation again.
Termination of a CP/M session requires no special action, except that it is necessary to remove
the disks before turning the power off to avoid random transients that often make their way to the
drive electronics.
1.7 BDOS Error Messages CP/M Operating System Manual
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