this is my current main.c.  the main changes are longer delay
in shutdown() if #e/*debug is present; one-minute delay at end
of shutdown() when a terminal panics; fiddled the computation
of kpages, apparently to give kernels on machines >64MB more memory.

i now also print the amount of memory at boot, as V6 Unix did,
but that's commented out here.

Notes:
Thu May 5 08:50:36 EDT 2005 rsc
    I'm not convinced the terminal kernels need yet more memory.
    
    As far as the delay is concerned, is this a multiprocessor 
    terminal?  If you're on a uniprocessor then it should not
    reboot on panic -- the if(active.ispanic && m->machno==0)
    case should trigger, leading into the for(;;)halt(); loop.
    
    What am I missing?
    

Thu May 5 12:43:00 EDT 2005 rsc
    Simplified the code a little - mp terminals should no longer
    reboot on panic.
    


Reference: /n/sources/patch/applied/dont-clear-the-screen-so-fast
Date: Tue May  3 05:42:10 CES 2005
Reviewed-by: rsc

--- /sys/src/9/pc/main.c	Tue May  3 05:38:28 2005
+++ /sys/src/9/pc/main.c	Tue May  3 05:38:25 2005
@@ -346,6 +346,7 @@
 	char *p;
 	int userpcnt;
 	ulong kpages;
+	// uvlong kb;
 
 	if(p = getconf("*kernelpercent"))
 		userpcnt = 100 - strtol(p, 0, 0);
@@ -353,6 +354,8 @@
 		userpcnt = 0;
 
 	conf.npage = conf.npage0 + conf.npage1;
+	// kb = (((uvlong)conf.npage * BY2PG)/1024);
+	// print("mem = %,llud.%3.3lludMB\n", kb/1024, ((kb%1024)*1000)/1024);
 
 	conf.nproc = 100 + ((conf.npage*BY2PG)/MB)*5;
 	if(cpuserver)
@@ -376,7 +379,12 @@
 		 * The patch of nimage is a band-aid, scanning the whole
 		 * page list in imagereclaim just takes too long.
 		 */
-		if(kpages > (64*MB + conf.npage*sizeof(Page))/BY2PG){
+		/* 64MB is not always enough with Gbe */
+		if(kpages > (96*MB + conf.npage*sizeof(Page))/BY2PG){
+			kpages = (96*MB + conf.npage*sizeof(Page))/BY2PG;
+			conf.nimage = 2000;
+			kpages += (conf.nproc*KSTACK)/BY2PG;
+		} else if(kpages > (64*MB + conf.npage*sizeof(Page))/BY2PG){
 			kpages = (64*MB + conf.npage*sizeof(Page))/BY2PG;
 			conf.nimage = 2000;
 			kpages += (conf.nproc*KSTACK)/BY2PG;
@@ -631,6 +639,8 @@
 			break;
 	}
 
+	if (getconf("*debug"))
+		delay(5*60*1000);
 	if(active.ispanic && m->machno == 0){
 		if(cpuserver)
 			delay(10000);
@@ -640,6 +650,12 @@
 	}
 	else
 		delay(1000);
+	/*
+	 * give the poor terminal user a chance to read the crash messages
+	 * before clearing the screen!
+	 */
+	if (active.ispanic && !cpuserver)
+		delay(60*1000);
 }
 
 void