I've commented out some of the code in s7.s to try and disable the

Graphics-2 I/O operations.

src/sys/s7.s

@@ -5,26 +5,26 @@ pibreak:			" priority interrupt break processing "chain"
    dac .ac			" save interrupt AC
 	"** CROSSED OUT....
 
-   dpsf
+   " dpsf		" Warren commented this code out to try and
-   jmp 1f
+   " jmp 1f		" disable the Graphics-2 I/O
 
-   dpcf
+   " dpcf
-   dprs
+   " dprs
-   dac dpstat
+   " dac dpstat
-   sma ral
+   " sma ral
-   jmp 2f
+   " jmp 2f
-   dprc
+   " dprc
-   dac dpchar
+   " dac dpchar
-   -1
+   " -1
-   dac dpread
+   " dac dpread
-   lac dpstat
+   " lac dpstat
-   ral
+   " ral
-2:
+" 2:
-   sma
+   " sma
-   jmp piret
+   " jmp piret
-   -1
+   " -1
-   dac dpwrite
+   " dac dpwrite
-   jmp piret	"** END OF CROSSOUT
+   " jmp piret	"** END OF CROSSOUT
 
 1: clsf			" clock overflow (line frequency ticks)?
    jmp 1f		"  no
@@ -88,24 +88,26 @@ cnop:			" fetched as constant in iread
    dac .dspb
    jmp piret
 dsprestart:
-   lac d1
+			" Warren commented this out to try and
-   dac .dspb			" set .dsbp = 1
+			" disable the Graphics-2 I/O
-   lac dspbufp			" load display buf pointer
+   " lac d1
-   beg				" start display processor
+   " dac .dspb			" set .dsbp = 1
-   -10
+   " lac dspbufp			" load display buf pointer
-   dac .dsptm			" set .dsptm = -10 (10 ticks)
+   " beg				" start display processor
-   jmp piret
+   " -10
+   " dac .dsptm			" set .dsptm = -10 (10 ticks)
+   " jmp piret
 
-1: sna ral			" dataphone flag set (bit 7)??
+" 1: sna ral			" dataphone flag set (bit 7)??
-   jmp .+3			"  no
+   " jmp .+3			"  no
-   raef				" XXX: fix comment
+   " raef				" XXX: fix comment
-   jmp piret			" return
+   " jmp piret			" return
-   sma				" light pen flags (bit 2)
+   " sma				" light pen flags (bit 2)
-   jmp 1f			"  no
+   " jmp 1f			"  no
-   lda				" G-2: load display address
+   " lda				" G-2: load display address
-   dac .lpba			" save
+   " dac .lpba			" save
-   rlpd				" G-2: resume after light pen stop
+   " rlpd				" G-2: resume after light pen stop
-   jmp piret
+   " jmp piret
 
 1: ksf				" (TTY) keyboard flag set?
    jmp 1f			"  no