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2        $seiten_id = 'gamma55';
3        $version = '$Id: gamma10.php 278 2012-07-18 12:55:44Z sven $';
4        $title = 'A second generation calculator: BULL GAMMA 55';
6        require "../../lib/technikum29.php";
9        <h2>A second generation calculator: The BULL GAMMA 55 (GE-55)</h2>
11         <div class="box center clear-after">
12                <img src="/shared/photos/rechnertechnik/bull-ge55.jpg" alt="BULL Gamma 55 Computer-Anlage" width="750" height="389" />
13                <div class="bildtext">
14                <p>On the left the printer I41 is visible, in the background the CPU (2m
15wide!) and on the right the paper tape puncher can be seen. On top of
16the desk is a punch card reader with an alphanumeric keyboard in front
17of it.</p>
18                </div>
19                </div>
20        <p>
21        We are since 2012 the proud owners of a new BULL computer system: A BULL Gamma
2255 (also known as GE-55 after the merge with General-Electric). The
23system now in the collection was stored in Switzerland with all
24accompanying documentation, punched cards etc. for 26 years.<br>
26It was developed in 1966 by BULL in France and hit the market in 1967.
27It was aimed at small and middle sized companies that were too small
28as customers for other, larger computer systems.<br>
30This computer demonstrates the tremendous advances of computer
31technology in the 1960s. While all instructions on the (larger) Gamma
3210 are implemented with a lot of active circuitry stepping through
33many cycles, this is done in the Gamma 55 by means of a rather large
34read-only-memory. This is an implementation of a microprogram which
35reduces the necessary hardware significantly, making the machine
36cheaper and more reliable.<br>
38The basic implementation of the machines makes heavy use of mechanical
39parts but at least the card reader is an optical device.<br>   
41<div class="box left">
42<a class="popup" href="/shared/photos/rechnertechnik/ge-55-2.jpg">
43                <img src="/shared/photos/rechnertechnik/ge-55-2.jpg" alt="Während der Restauration" width="565" height="323" /></a>
45                <div class="bildtext"> 
46        <p>The system during the refurbishment of
47the cabinets <a class="popup" href="/shared/photos/rechnertechnik/ge-55-2.jpg"> (enlarge picture) </a><br> </p>
48                </div>
49                </div>
52<p>Our machine can be programmed in machine language or some kind of a
53mini-COBOL (Common Business Oriented Language). The compiler is loaded
54via punched cards. To start a program a Supervisor that is loaded by
55punched cards is necessary.<br>
57The system was advertised with 2.5 kB, 5 kB or 10 kB of main memory
58(core memory). Our machine has 5 kB of memory and it is really
59astonishing that a high level language like COBOL - even our
60mini-COBOL - is feasible with such a tiny amount of memory at all.<br>
62As an extension a memory drum was offered which also allowed the use of
63a mini-FORTRAN (FORmula TRANslator).<br>
65Although BULL was quite inventive concerning software their hardware
66was quite outdated. The boards used in this machine are the same as
67those in the earlier GAMMA 10 (based on Germanium transistors). At the
68same time other companies like UNIVAC or IBM already employed
69integrated circuits (DTL, Diode-Transistor-Logic) for their machines.<br>
70    </p>
72September 2013: <b id="ge-55">Success! The machine is up and running!</b><br>
73After a substantial amount of time spent for debugging, the machine is now
74fully operational again. More the 30 (!!) defective transistors and diodes had to
75be traced down and replaced to achieve this. These parts failed silently
76during the 33 years in storage. We can now proudly state that this is the
77only surviving Gamma 55 on earth which is still running. If you are
78interested in details concerning the architecture and programming of the
79machine, have a look here (in German only): <a href=""> BULL Gamma 55 manuals </a> </p>
81<div class="box left">
82                <a class="popup" href="/shared/photos/rechnertechnik/leser617.jpg">
83                <img src="/shared/photos/rechnertechnik/leser617.jpg" alt="Card-Reader" width="402" height="249" /></a>
84                <div class="bildtext">
85                <p>Card-Reader <a class="popup" href="/shared/photos/rechnertechnik/leser617.jpg">(enlarge picture)</a><br> </p>
86                </div></div>
87The card reader of the GE55 can be seen on the left of the pictures (without
88its cover. It is interesting to see that Bull solved every problem for which
89as (practical) mechanical solution exists in a mechanical way (as compared to
90our times where microcontrollers are abundant even in applications which
91might be implemented more easily with a mechanical approach). The card is
92coupled to a punched tape which generates the clock signal for reading the
93card's columns. Although this part can wear out easily, it is nevertheless an
94ingenious solution.<br>
95Also visible is the projection display: 10 digits and two
96additional symbols are displayed by an array of incandescent lamps with
97associated lenses. This is the main way of communicating with the machine
98like today's video terminals.
99The picture below shows the read-only-memory containing 1024 words. A very
100heavy contraption but very maintainable. (Both pictures can be enlarged by
101clicking on them.)
104                <div class="box right">
105                <a  class="popup" href="/shared/photos/rechnertechnik/ge55-rom.jpg">
106                <img src="/shared/photos/rechnertechnik/ge55-rom.jpg" alt="Read-only-memory" width="399" height="259" /> </a>
107                <div class="bildtext">
108                <p>Right: Read-only-memory removed from the machine.
109 <a  class="popup" href="/shared/photos/rechnertechnik/ge55-rom.jpg">(enlarge picture)</a><br></p>
110                </div>
111                </div>
113        <div class="cols">
114<div class="leftcol">
115<p class="small">Contemporary document: In the following you find some quotations from
116the system description published in 1967/1968:<br>
117<blockquote><p class="small">"After intensive market research, BULL GENERAL ELECTRIC developed a
118versatile computer system: Its internal structure resembles that of
119modern computers. Furthermore it is a data processing system that
120allows direct input via keyboard. It is a real data processing system
121because it can grow with your needs and its memory capacity (internal
122as well as external) can be extended.<br>
124Construction: The central processing unit (CPU) of the GE-55 supports
125four channels; three of which are normal speed channels for slow
126input/output devices and one high speed channel used by external
127memory units or a fast line printer...<br>
128....the cycle time is 7.9 us. Characters are represented by their
129respective ISO-code. The core memory is used as data and program
130memory. A since byte, comprised of 8 data bits and one parity bit,
131stores a single alphabetical character or up to two numerical
134<div class="rightcol"><blockquote><p class="small">
136Instructions are analyzed and executed under control of a
137read-only-memory with a capacity of 1024 word of 36 bits each... This
138memory contains micro programs for control, supervision and execution
139as well as arithmetic and character conversion tables.<br>
141Software: The programming system is mainly comprised of the following
142parts: Symbolic languages that facilitate the actual programming task
143and an assembler for translating assembler programs to machine
147<div class="clear">&nbsp;</div><br>
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