System information

Console Commands
MicroVax 3100 Models 88/98 User Information
A-25
characters,including the checksum and separating space,
into an 8-bit register initially set to zero. The
line_checksum does not include the terminating carriage
return, rubouts, or characters deleted by a rubout. If no
errors occur, the result is zero.
If the line_checksum is correct, the console responds with
the input prompt and either sends data to the requester or
prepares to receive data.
If the line_checksum is in error, the console responds with an
error message. This prevents the operator from inadvertently
entering into a mode where the console accepts characters
from the keyboard as data and does not provide an escape
mechanism.
{data}\ If the command is a load (bit 31 of the count is clear), the
console responds with the input prompt (>>>), then accepts
the specified number of bytes of data to be put into memory
and an additional byte of received data_checksum. The data
is verified by adding all data characters and the checksum
character into an 8-bit register initially set to zero. If the
final content of the register is nonzero, the data or
checksum is in error, and the console responds with an
error message.
If the command is a binary unload (bit 31 of the count is set),
the console responds with the input prompt (>>>), followed
by the specified number of bytes of binary data. As each byte
is sent, it is added to a checksum register initially set to zero.
At the end of the transmission, the two's complement of the
low byte of the register is sent.
{data_checksum}\ If the data_checksum is incorrect on a load, or if memory or
line errors occur during the transmission of data, the entire
transmission is completed, and the console issues an error
message. If an error occurs during loading, the contents of
the memory being loaded are unpredictable.)
The console represses echo while it is receiving the data string and checksums. The
console terminates all flow control when it receives the carriage return at the end of the
command line to avoid treating flow control characters from the terminal as valid
command line checksums.