5 Hole Paper Tape

Mus.Cat. NEWUC:2003.86 Mnfctr: Creed & Co Ltd Date: 1955 Ser. No: 5270 Model: 7P/N4
Comp: Paper Tape Punch Width: 600 mm Depth: 378 mm Height: 393 mm Weight: 21.5 Kg

Paper Tape Perforator.

When the first computers were being constructed
the only media were either 5-hole paper tape used in the Telegraph Service
or punch cards invented by Herman Hollerith to process the 1890 American census.

This is a five hole paper tape perforator.
Above the keyboard is the container for the reel of blank tape
which is threaded down to the punch at the left.

The coding sheet would be underneath the black horizontal rule.

Note that there is no display or printing of what is being punched.

Close-up of punch.

An electro-mechanical device par excellence.
These devices were built as if they were going to be used in a tank in battle field conditions.

This one needs a good servicing and cleaning.

Rear view of punch.

This is the rear view.
It is made out of cast-iron and steel with a metallic enamel finish.

It weighed 21.5Kg. Go and find something weighing 20Kg, and try lifting it.
If you have a bad back or hernia problem, Don't.

It is almost 50 years old and in very good condition.

Might try powering it on one day, and punching some paper tape!

Pegasus Computer

This description of 5 hole paper tape is as used with the FERRANTI PEGASUS COMPUTER in 1956.
5 hole paper tape was also used with the ILLIAC computer (1952),
and the COLOSSUS computer (1944) constructed to break the coded messages sent by the German military.

Perforator Keyboard

5 hole paper tape can encode 25=32 characters, but a perforator keyboard had 60 keys!

Perforator Keyboard

The keys were in 3 groups. The 28 coloured yellow are operable when the keyboard is in letter shift.
The 28 coloured pink when the keyboard is in figure shift.
The 4 coloured green are operable in either shift.
The RUN OUT key produces blank paper tape continuously while it is depressed.
(Blank character is the same as NUMERIC SHIFT.)

So, for instance, the letter B and the figure 2 both produced the same hole punch code.
How that code was interpreted depended on whether a "FIGURE SHIFT" or a "LETTER SHIFT" was last read.

The following is from "A Programming Manual for the Ferranti Pegasus Computer",
Reference CS.50, ISSUE 1. printed by FERRANTI LTD. October 1955.
Museum Catalogue Number: NEWUC:2004.20

CodeLetter Shift Figure Shift CodeLetter Shift Figure Shift
000.00FS FS 100.00P 0
000.01A 1 100.01Q >
000.10B 2 100.10R
000.11C i* 100.11S 3
001.00D 4 101.00T
001.01E ( 101.01U 5
001.10F ) 101.10V 6
001.11G 7 101.11W /
010.00H 8 110.00X x
010.01I 110.01Y 9
010.10J = 110.10Z +
010.11K - 110.11LS LS
011.00L v 111.00. .
011.01M LF 111.01? n
011.10N Space 111.10 CR
011.11O , 111.11Erase Erase

In HTML (The language used to create WEB pages like this one),
we do not have all the characters used with the PEGASUS computer.

FS is Figure Shift and enables the pink keys.
LF is Line Feed and causes a printer to advance one line.
Space causes a printer to move one character to the right, printing nothing.
LS is Letter Shift locks the pink keys and enables the green keys.
CR is Carraige Return and causes the printer to begin printing at the left end.
Erase is ignored.

The meaning and use of v and n is unknown to the author of this.

But an email received 26 January 2006 throws some light on their use:

I was looking at your museum photographs again and noticed your
uncertainty about the script v and n symbols. Pegasus had an early
primitive higher level programming system called Pegasus Autocode with
variables denoted v1, v2, v3 etc. and integers n1, n2, n3 etc. but which
used the script v and n. You could make statements like

v1=v2+v3 or n1=n1+1

using the standard arithmetic operators. (It also had conditional goto's
and labels if I remember correctly).

Jim Eve.
Back to Paper Tape.