VBN is a program to "edit" a file, given the file-spec, a VBN (virtual block number), an offset into the block, and data that will overlay the existing data. This program is similiar to the MEDUSA program, which did modifications based on LBN. To use the program, enter:   $ RUN VBN  VBN prompts with: Enter file spec: If you enter only a carriage control, VBN terminates. Otherwise, it prompts again with:   Enter VBN (decimal):  If you enter only a carriage control, VBN issues the earlier prompt. Otherwise, it displays a hex and ascii version of the block that you specified, and then prompts with:   Enter offset (hex):  If you enter only a carriage control, VBN issues the earlier prompt. Otherwise, VBN prompts with:   Enter new value (hex or ascii):  If tou enter only a carriage control, VBN issues the earlier prompt. You can enter a one-byte hex data value, or a character string enclosed in single quotes. Note that the character string can be longer than one byte, but must not exceed the boundary of the vbn. VBN then displays the altered block and prompts with: ! " Ok to write back to file (Y/N): # $If you enter anything besides an uppercase "Y", VBN terminates, without %altering the block. If you enter "Y", the block is re-written, and VBN &returns to the "Enter VBN (decimal)" prompt. ' ( )The files in this directory include: * + AAAREADME.TXT - This text file , BLD.COM - Proc to build VBN program - VBN.FOR - VBN source program . /This program was something of a quick hack, and I hope to make enhancements 0by the next DECUS. 1