hcu - call the host system




Calls up the host system on a directly connected serial line (/dev/ttyp1) and manages an interactive conversation with possible transfers of files.

After making the connection, hcu performs two functions: the transmit function reads data from the standard input and, except for lines beginning with ~, passes it to the host system; the receive function accepts data from the host system and passes it to the standard output.

Lines beginning with ~ have special meanings. The transmit function interprets these lines as follows:

terminate the conversation with the host. This command logs you off the host and returns to the ELF monitor.

escape temporarilty to the ELF monitor. This command does not explicitly log you off the host. To resume communication with the host, enter another hcu command.

~%xtake !from [ to ]
copy an executable file from (on the host system) to file to on the satellite system. If to is omitted, the from argument is used in both places. If the satellite file does not exist, it will be created with read/write/execute permission set and size matching the size of the file on the host. If the satellite file exists and is writable, its size will be changed to match that of the host.

~%atake !from [ to ]
same as xtake but for non-executable files (usually ASCII). Does not set execute permission.

~%xput from [ !to ]
copy an execuatble file from (on satellite system) to file to on host system. If to is omitted, the from argument is used in both places.

~%aput from [ !to ]
same as xput but for non-executable files (usually ASCII).

enable flow control so that the system sends out the stop character (control s) when its internal queue is close to overflowing on input, and sends the start character (control q) when it is ready to accept further input. Users may also issue stop and start characters from the console terminal. This is the default mode.

disable flow control, disallowing the use of stop (control s) and start (control q) characters to control the flow of characters between the host and the satellite. This mode is used, for example, when the user wishes to send the stop and start characters as input to the host rather than using them for flow control.

send the line ~... to the host system. This sequence is necessary when communicating to a third system via the cu(1C) command on the host system.

Because of the difference in byte and word orders between the VAX-11-750 and the Motorola 68000, files created on one system need to be massaged in order to be correctly read on the other system. The transfer facility only handles ASCII files and executable files. A user that that transfers binary files, other than executable files, is responsible for writing a program to correctly interpret those files.


create(1F) , chsize(1F) , chmod(1F) , link(1P) , cp(1F)