11/3/71                                            SYS WRITE (II)





NAME            write  --  write on file



SYNOPSIS        (file descriptor in r0)

                sys     write; buffer; nchars   / write = 4.

                (number written in r0)



DESCRIPTION     A file descriptor is a word returned from a suc-

                cessful open or creat call.



                buffer is the address of nchars contiguous bytes

                which are written on the output file.  The number

                of characters actually written is returned in r0.

                It should be regarded as an error if this is not

                the same as requested.



                For disk and tape files, writes which are multi-

                ples of 512 characters long and begin on a 512-

                byte boundary are more efficient than any others.



FILES           --



SEE ALSO        sys creat, sys open



DIAGNOSTICS     The error bit (c-bit) is set on an error: bad de-

                scriptor, buffer address, or count; physical I/O

                errors.



BUGS            --



OWNER           ken, dmr