diff --git a/btester.sh b/btester.sh
new file mode 100755
index 0000000..a956a7e
--- /dev/null
+++ b/btester.sh
@@ -0,0 +1,11 @@
+#! /bin/sh
+
+pdpy11 --lst tester.mac
+
+if [ ! -e raw_to_simh_bin ] ; then
+	g++ -Ofast raw_to_simh_bin.cpp -o raw_to_simh_bin
+fi
+
+./raw_to_simh_bin tester 512 512 tester.bin
+
+ls -la tester*
diff --git a/raw_to_simh_bin.cpp b/raw_to_simh_bin.cpp
new file mode 100644
index 0000000..3d7b3d3
--- /dev/null
+++ b/raw_to_simh_bin.cpp
@@ -0,0 +1,72 @@
+// this program is in the public domain
+// written by Folkert van Heusden <mail@vanheusden.com>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void put_byte(const uint8_t byte, int32_t *const csum, FILE *const fh)
+{
+	*csum -= byte;
+
+	fputc(byte, fh);
+}
+
+int main(int argc, char *argv[])
+{
+	if (argc != 5) {
+		fprintf(stderr, "Usage: %s file_in load_offset start_offset file_out\n", argv[0]);
+		fprintf(stderr, "Note: offsets must be decimal\n");
+
+		return 1;
+	}
+
+	const char     *file_in  = argv[1];
+	const uint32_t  offset   = atol(argv[2]);
+	const uint32_t  start    = atol(argv[3]);
+	const char     *file_out = argv[4];
+
+	FILE           *fh_in    = fopen(file_in,  "r");
+	FILE           *fh_out   = fopen(file_out, "wb");
+
+	fseek(fh_in, 0, SEEK_END);
+	uint32_t        file_size = ftell(fh_in);
+	fseek(fh_in, 0, SEEK_SET);
+
+	int32_t         csum = 0;
+
+	// header for the data itself
+	// after the data, a header will follow setting
+	// the start address
+	put_byte(0x01, &csum, fh_out);
+	put_byte(0x00, &csum, fh_out);
+
+	uint32_t        temp = file_size + 6;
+	put_byte(temp & 255,   &csum, fh_out);
+	put_byte(temp >> 8,    &csum, fh_out);
+
+	put_byte(offset & 255, &csum, fh_out);
+	put_byte(offset >> 8,  &csum, fh_out);
+
+	for(int i=0; i<file_size; i++) {
+		uint8_t c = fgetc(fh_in);
+
+		put_byte(c, &csum, fh_out);
+	}
+
+	fputc(csum & 0xff, fh_out);
+
+	put_byte(0x01, &csum, fh_out);
+	put_byte(0x00, &csum, fh_out);
+
+	put_byte(6,    &csum, fh_out);
+	put_byte(0,    &csum, fh_out);
+
+	put_byte(start & 255, &csum, fh_out);
+	put_byte(start >> 8,  &csum, fh_out);
+
+	fclose(fh_out);
+
+	fclose(fh_in);
+
+	return 0;
+}
diff --git a/tester.mac b/tester.mac
new file mode 100644
index 0000000..9d6ee61
--- /dev/null
+++ b/tester.mac
@@ -0,0 +1,52 @@
+; in simh:
+; simh> set console telnet=3333
+; then invoke telnet to port 3333 on the simh systm
+; simh> load test.bin
+; simh> run
+
+
+; initialize stack pointer
+start:	MOV	#1000, R6
+
+	MOV	#textstart, R0
+	CALL	printstart
+
+
+	MOV	#textfin, R0
+	CALL	printstart
+	TRAP	7
+
+; store copy of R0 on the stack
+printstart:	MOV	R0,-(SP)
+; store PSW (status register) on stack
+	MFPS	-(SP)
+
+; string ends with 0x00
+print:	TSTB	(R0)
+	BEQ	pdone
+
+; put character in tty buffer
+	MOVB	(R0), @#TTYTX
+
+; wait for it to be transmitted
+waittx:	TSTB	@#TTYST
+	BPL	waittx
+
+	INC	R0
+	JMP	print
+
+; retrieve stored r0, r1 and psw from stack
+pdone:	MTPS	(SP)+
+
+	MOV	(SP)+,R0
+	RET
+
+	make_raw
+
+textstart:	.ASCII	"tester running...\r\n\x00"
+textfin:	.ASCII	"tester finished\r\n\x00"
+
+textbuffer:	.BLKB	256.
+
+TTYST	=	177564
+TTYTX	=	177566