Just a note:
To get /dev/pm0 (so I could symlink /dev/mouse -> /dev/pm0) I used
this patch.  Apply at your own risk...

 - Arne H. J.

--- conf.c.orig	Mon May 15 22:49:12 1995
+++ conf.c	Fri May 12 11:50:16 1995
@@ -116,6 +116,8 @@
 cdev_decl(rcons);
 #include "fb.h"
 cdev_decl(fb);
+#include "pm.h"
+cdev_decl(pm);
 
 struct cdevsw	cdevsw[] =
 {
@@ -127,7 +129,7 @@
         cdev_ptc_init(NPTY,ptc),        /* 5: pseudo-tty master */
 	cdev_log_init(1,log),		/* 6: /dev/klog */
 	cdev_fd_init(1,fd),		/* 7: file descriptor pseudo-dev */
-	cdev_notdef(),			/* 8: 2100/3100 frame buffer */
+	cdev_fb_init(NPM,pm),		/* 8: 2100/3100 frame buffer */
 	cdev_notdef(),			/* 9: old slot for SCSI disk */
 	cdev_tape_init(NTZ,tz),		/* 10: SCSI tape */
 	cdev_disk_init(NVND,vnd),	/* 11: vnode disk driver */