From: utzoo!decvax!ucbvax!C70:bitgraph
Newsgroups: fa.bitgraph
Title: Re: Bugs in Firmware
Article-I.D.: ucb.1531
Posted: Fri Jul 16 14:30:04 1982
Received: Sat Jul 17 02:31:28 1982

>From edmond@BBN-UNIX Fri Jul 16 14:29:34 1982
   Probably the reason for the gray rectangle is the use of DEL characters
for padding functions like Insert and Delete Line.  The BitGraph displays
DELs as a box, where the H19 and the VT52 discard DELs.  The TOPS-20 EMACS
likes to use DEL characters for padding.  Other TOPS-20 and TENEX programs
also prefer DEL to NUL, since NUL is often used as a string terminator by
operting system functions.
 -WBE