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2        $seiten_id = 'fruehe-computer';
3        $version = '$Id: early-computers.php 488 2014-01-06 16:04:53Z heribert $';
4        $titel = 'Scientifical calculators and mini computers';
6        require "../../lib/technikum29.php";
9<h2>Scientifical calculators and mini computers</h2>
11<h3 id="lpg21-en">Schoppe & Faeser:  LGP-21 (General Precision) </h3>
13        <!-- Bild über ganze Breite (geht bei schmalen Monitoren ins Menü rein) -->
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15    <div class="box center" style="position:relative;">
16       <div style="position:absolute; top:0px;"><img src="/shared/photos/rechnertechnik/lgp-21.jpg"  width="872" height="414" alt="LGP 21 Computeranlage" />
18        <div style="height: 443px;">&nbsp;</div>
19                <p class="bildtext small">From left to right: magnetic tape drive, 1. LGP-21, Tally paper-tape-reader and punch, 2. Tally reader, two additional hard drives, 2. LGP-21, Flexowriter</p>
21    </div>
23                <p>This machine is particularly interesting in more than one way: 1) The hardware
24is extremely simple, 2) the machine already employs a bus system for
25interconnecting the various units. 3) The machine features a fixed disk which
26holds all registers as well as timing tracks. As the picture above shows we
27have two complete systems which simplifies troubleshooting and repair.<br>
29Citing from the original brochure (1964): "The LGP-21 is produced by Schoppe &
30Faeser as a licensee in Europe and is distributed by EUROCOMP GmbH."<br>
32The LGP-21 had been developed by Librascope, division GP1 (USA). This company
33once was one of the largest calculating machine manufacturers in the world.
34Starting in 1962 the LGP-21 was marketed in the USA by General Precision. The
35machine is a very small computer but was advertised as "The first complete
36program controlled digital computer for only $16,250 in the minimum
37configuration." This configuration consisted of the CPU and a Flexowriter only.
38This machine was the successor of the LGP-30 (1st generation, 1956, also build
39by Schoppe & Faeser in Germany as a licensed product). The LGP-21 is very rare
40- only about 100 machines were built in Germany. Even rarer is the magnetic
41tape unit of which only 5 known units were built. The machine in the museum has
42serial number 4.</p>
44<div class="box left clear-after">
45                <img src="/shared/photos/rechnertechnik/tally-lochstreifenleser.jpg" width="603" height="241" alt="Tally Lochstreifenleser" />
46                <p class="bildtext small">The external memory of the LGP-21 are perforated papertapes, which are scanned mechanically of the Tally-tape reader. The magnetic tape drive and other external drives were added in the late 60s.</p></div>
48<p>As external storage the LGP-21 employs a paper tape system using Tally
49papertape readers. The magnetic tape unit and two external disks with a
50capacity of about 8000 words each were added in the late 1960s.<br>
52A rotating disk serves as the machine's main memory and clock generator. It
53rotates with 1475 RPM and holds 4096 words of 32 bits each which equals 12 kB,
54a reasonable size back then. The disk contains 64 data tracks, four timing
55tracks and tracks for three registers (accumulator, instruction register and
56counter register). The mean write density is about 10 Bit/mm (about 1/200th of
57today's disk drives).<br> Here you can see a picture of the
58<a  class="popup" href="/shared/photos/rechnertechnik/lgp21-platte.jpg"><b>LGP-21 disk drive</b></a><br>
60The LGP-21 supports 23 different instructions - enough to program typical
61scientific applications.<br>
63Repairing the machine turned out to be quite a challenge. Having two machines
64of this type helps a lot.
66More information about this interesting and rare system will follow.</p>
73        <h3>Mini-Computers</h3>
75    <p>Today's kids think of the latest mobile devices when talking about "mini computers".
76           In contrast, in the 1960s and the early 70s, a computer was always huge (like our
77           <a href="univac9400.php">UNIVAC mainframe</a>), thus a 300kg computer was "mini".
78           Early computers are well worth seeing due to their enormous size and the nice
79           transparent auxillary devices.
80       <br />There is a very important computer family that finally lead to (today's)
81           personal computers: The development of the "Mini" computers from Digital Equipment
82           Corporation (DEC), series PDP-8 and PDP-12 (both 12-bit architecture). The museum
83           owns a complete production run from that devices: From the PDP-8 (also called
84           Classic-8), year of manufacture 1965 to the PDP-8a (1975, this one is less
85           important so it is located in the archive). PDP means Programmed Data Processor.
86        </p>
87        <div class="box left clear-after">
88        <img src="/shared/photos/rechnertechnik/dec/flip-chip-module.jpg" width="400" height="173" alt="Flip-Chip-Module" />
89                <p>The manuals of these computers are very detailed, with full circuit
90                   documentation. There never have been any other computer with such an
91                   elaborate documentation. For restoration purposes these manuals are
92                   indispensable. Even in those days, other manufacturers kept their
93                   blueprints in secret for fear of unauthorized re-use (e.g. HP).
95                </p>
96        </div>
98        <p>For further reading see the story about <a class="go" name="backlink-dec"
99        href="/en/devices/dec-history.php">Rise and Fall of DIGITAL (Equipment Corporation)</a>.</p>
101    <h3 id="pdp8">Classic PDP-8</h3>
102        <div class="box left clear-after">
103                <img src="/shared/photos/rechnertechnik/dec/pdp-8.jpg" width="400" height="560" alt="PDP 8 Classic" />
104                <img style="clear:left" src="/shared/photos/rechnertechnik/dec/pdp-8,pannel.jpg" width="400" height="300" alt="PDP-8 Bedienungspannel" />
105                <img style="clear:left" src="/shared/photos/rechnertechnik/dec/pdp8-fluegel.jpg" width="400" height="345" alt="PDP-8 Flügel" />
108                <p>PDP computers were especially used by scientists. By using self-made
109                   (CPU) interface boards, already existing (experimental) equipment could easily
110                   migrated to the new hardware. DEC even offered prefabricated boards to
111                   encourage own extension development.
112                   The figure above shows a typical second generation module (1965) without ICs
113                   from the classic PDP-8 on the left. In the middle is a smaller third generation
114                   module with ICs (from 1967) which was used in the PDP-8i, PDP-8L and PDP-12.
115                   On the right is an empty module just suitable for being equipped by the
116                   user for interfaces to own periphery.<br>
119         One of the museum highlights: The complete PDP-8 system with processor,
120         a big tape deck TU-580 (originally belonged to the PDP-5, manufactured in 1963),
121         punch card reader/puncher PC-01, hard-disc DF-32 with immovable heads
122         and a teletype as printer. The Classic PDP-8 is considered the world's first mass-produced
123         "minicomputer". Due it's use of ICs, unlike its predecessors, it is considered
124                 a second-generation computer.
125        </p>
127                <p>This computer features various different logic and register modules. All logic
128                is only built with NAND and NOR gatters. Registers are constructed with flip-flop
129                circuits. The extensive wiring of the modules (see picture) is called
130                <a href="">Wire wrapping</a>. This kind of
131                connections were used in all bigger computers until the 1980s, since it is an
132                easy way to connect two points which are not mounted on the same board or on the
133                same level. In the early days this wiring was manually performed and later executed
134                by machines. Even today there are still some wire-wrap-connections in testing
135                environments.
136                <br>
137                The picture shows the uncovered computer with opened right wing where you can easily
138                see the wire-wrap connections.</p>
140                <p class="small">Top: Complete PDP-8 system, <br/> center: console of the computer <br/> below: open computer, the right wing is extended. Here you can see the wire-wrap connections.<br><br>
141                The processor and the tape reader are on loan from the <a href=""> "FITG"</a>, Frankfurt (Germany)</small>
143                </div>
144         <!-- The <b>Classic PDP 8</b> from DEC (Digital Equipment Corporation, Massachusetts):
145         He is considered to be the world's first mass-produced "minicomputer" (1965). "Mini" is relative: Only too very
146         strong men can lift the computer. It is better to have four people to carry it!.
147         Without ICs or their ancestors the device is counted among the seccond-generation calculators.
148         <br/>You can also get a view from the "Flip-Chip"-card from the <a class="go" href="/en/devices/pdp-8-left-flank.php">left flank</a>
149         (<u>flank</u>). The core memory is set above (storage capacity 4kB).-->
153  <h3 id="pdp8i">PDP-8I</h3>
154    <div class="box left">
155        <img src="/shared/photos/rechnertechnik/dec/pdp8i.jpg" alt="DEC PDP-8I" width="400" height="666" />
156        </div>
157        <div style="margin-left:400px; min-width: 450px;">
158                <div class="box center auto-bildbreite">
159                        <img style="float:none" src="/shared/photos/rechnertechnik/dec/8i-pannel.jpg" width="400" height="292" alt="PDP 8i operator panel" />
160                        <p class="bildtext small">Left: The PDP-8i system with two-DECtapes TU 55, hight-speed paper tape reader/punch
161                                PC 04, 563 CALCOM plotter (top) and a TELETYPE (not shown). Above: the computer console</p>
162                </div>
163        </div>
165          <p>In 1967 the first series 74xx TTL ICs (transistor-transistor logic) came on the market.
166             DEC was at the bleeding edge, releasing the 8i ("with <b>i</b>ntegrated circuits"). No one
167                 knew about the stability of the new ICs (later bugs). Therefore UNIVAC used the well established
168                 DTL technology even two years after. Fortunately, the TTL ICs proved to be as stable as the DTL
169                 series. Since the integration degree was much higher, less space has been needed for computers.
170                 <br>DEC's first calculator with integrated circuits was very expensive. The CPU on alone
171                 (in the picture: Left case, middle) cost US$ 27,000 without peripherals at that time.
172         <br>The main memory had a capacity of 8kB. While computing a "large" problem, it was possible to swap
173         programs or data to files on magnetic tape and read in afterward be reread. DEC developed
174         an intelligent operating system (OS/8) which worked very efficiently with such little memory.
175         It is very interesting to watch this computer working.</p>
176         <p>If you have not been in the presence of this computer, you should know that it is quite large.
177         With the plotter, it stands at a height of almost 7' (2m) and weighting at more than 600 lbs (300kg).</p>
178         <p>The peripherals consist of two TU-55 (tape drives), a PC-04 (high speed paper tape reader),
179         Calcomp 563 plotter (at the top) and of course a teletype (not pictured).
180        </p>
183        <h3 id="pdp8L">PDP-8L</h3>
184        <div class="box desc-left borderless">
185                <img src="/shared/photos/rechnertechnik/dec/pdp-8L.jpg" width="400" height="360" alt="DEC PDP-8L" />
186                <p class="small">PDP-8L (build in 1968) with HSR Paper Tape Reader</p>
187        </div>
188        <div class="box clear-after">
189                <p>Many DEC customers did not need the high memory capacity or installable options.
190                Therefore DEC developed the stripped-down computer PDP 8L (<b>L</b>ow-cost) with
191                only a few pre-wired installed options in the lower price range.
192                The core memory had only 4kB capacity, it was extendable to 8kB with an external cabinet.
193                <br>Our PDP-8L has many extensions: HSR (High Speed) paper tape reader, TC01 Tape Control
194                with two drives TU55 and additional memory.
195                <br>DEC invented the interpreted programming language <b>FOCAL</b> (Formulating Online
196                Calculations in Algebraic Language), which allowed the user an interactive
197                programming environment (like a Unix shell). This language is similar to BASIC, but
198                slightly simpler. FOCAL required no operating system and ran smoothly with 4kB core
199                memory and lacking mass storage.
200        </div>
203 <h3 id="pdp12">PDP-12, LAB-12</h3>
204 <div class="box left">
205      <img src="/shared/photos/rechnertechnik/dec/pdp-12.jpg" width="400" height="485" alt="DEC LAB-12" />
206 </div>
207 <div class="box center" style="min-width: 840px;">
208          <img src="/shared/photos/rechnertechnik/dec/pdp-12-konsole.jpg" width="400" height="256" alt="LAB-12 Bedienungspannel" />
209 </div>
211                        <p>The PDP-12 was released in 1969. Just 755 units were sold worldwide. It was the last series that
212                        could operate in LINC-Mode (it could be switched to either LINC-8
213                        or PDP-8). This is a laboratory computer, equipped with AD and DA
214                        converter as standard. Such computers were usually kept up to date
215                        with hardware updates. The memory of this device was gradually
216                        increased from 8kB up to 32kB (DW 08E storage extension).
217                        <br>Besides the tape drives, the computer was also equipped with
218                        an 8-inch floppy drive. Afterwards they were removed again in
219                        favor of two removable disk drives. Finally they even tied the
220                        device to 10BASE-T ethernet, using a selfmade controller with an
221                        handwritten TCP/IP stack on a selfmade operating system.
222                        Thus this device can demonstrate the era from paper tapes up to
223                        today's storage standard.<br>
224                        Check out the console in a large scale:
225<a class="popup" href="/shared/photos/rechnertechnik/dec/konsole,dunkel.jpg">PDP-12 console (dark picture)</a> 
226or: <a  class="popup" href="/shared/photos/rechnertechnik/dec/konsole,hell.jpg">PDP-12 console (ligh picture)</a>
227                        </p>
229        <div class="desc-right borderless">
230      <img src="/shared/photos/rechnertechnik/dec/pdp-12-innen.jpg" width="297" height="676" alt="DEC LAB-12-Flip-Chips" />
231          <p class="small">The picture on the left shows the PDP-12 inner life with all 462 Flip-Chip-Boards.</p>
232        </div>
234        <p>By having all the following options, our computer was very comfortable
235        (the number in parentheses indicates the number of neccessary boards):</p>
237        <dl>
238                <dt>AD12 [A-D-Control] (12 modules):
239                <dd>The AD12 includes 16 channels of input, 10bit output resolution and features
240                    up to 60kHz signals at 30dB down.
242                <dt>DM12 [Data Break Multiplexer for KF12-B] (6 modules):
243                <dd>The DM12 provides the capability of operating up to three data break devices.
244                    The Data Break facility allows an I/O device to transfer information directly
245                        with the PDP-12 core memory on a cycle-stealing basis. This is particulary
246                        well suited for high-speed devices which transfer large amounts of information
247                        in block form. Peripheral I/O equipment  could reach a maximum transfer rate
248                        of 6,5 Mbit/sec.
250                <dt>DP12A [TTY-Dataphone] (4 modules):
251                <dd>The DP12 options permit interfacing additional Teletypes and Modems. They are
252                    capable of accepting data asynchronously up to 100,000 baud. The units are
253                        designed for US-ASCII and meet the EIA-standard (RS232) requirements.
255                <dt>DR12 [Relays and Control] (1 module):
256                <dd>The relay buffer is a six-bit register connected to six relays that are mounted
257                    on the data terminal panel. They can be used for controlling experiments or
258                        external equipment not otherwise directly interfaced with the PDP-12 Computer.
259                        The states of the relays can be examinede at any time via the register.
261                <dt>KE12 [Extended Arithmetik Element] (14 modules):
262                <dd>The EAE enables the CP (the DEC operating system) to perform arithmetic
263                    operations at higher speed. The ALU is extended by asynchronous logic such as a
264                        12-bit Multiplier Quotient Register and a 5-bit Step Counter.  These components
265                        are used by auxillary CPU instructions (opcodes).
267                <dt>KF12 [Multi Level] (54 modules):
268                <dd>The Multi-Level Automatic Priority Interrupt is designed to reduce the CPU
269                    overhead during the servicing of program interrupts. Up to 15 levels of interrupts
270                        can be accomodated with each level having an unique vector address. The interrupts
271                        can be accepted from other options (CPU extensions) or from up to six external
272                        devices. Storing of priority and vectoring of interrupt service routines is
273                        performed with a Stack.
275                <dt>KT12 [Time-Sharing Option] (2 modules):
276                <dd>This module provides the additional logic circuits required for the PDP12 Time
277                    Sharing System. Having satisfied the minimum equipment, it perimts up to 16 users
278                        to operate their individual programs in an apperantly simultaneous manner. The
279                        system is controlled by a group of subprograms called "TSS/12 Monitor".
281                <dt>KW12-A [Real Time Clock] (19 modules):
282                <dd>The RTC can be used to generate Program Interrupts over a range of intervals of
283                    2.5us to 40.96s; detect external and internal events in order to count them,
284                        measure them against a time base, measure the interval between them, use them as
285                        time base standard or control sample times of A/D conversions. In our system
286                        this module was used to connect the german longwave time signal radio station
287                        DCF77 in order to recieve the atomic clock time from the German master clocks
288                        in Frankfurt.
289        </dl>
291        <p>The computer is equipped with further cabinets which allow much more peripherals:</p>
293        <div class="desc-right no-copyright borderless">
294       <img src="/shared/photos/rechnertechnik/dec/pdp-12anwendung.jpg" width="400" height="366" alt="Typical PDP-12 in scientific environment" />
295           <p class="bildtext small">Typical picture in the 1970s: PDP-12 in the scientific domain. [Source: "digital products and applications, 1971"]</p>
296        </div>
298        <dl>
299                <dt>AA50P [12 Bit DAC Controller]
300                <dd>Cabinet to upgrade the number of digital-analog converters (half filled in our setup)
302                <dt>BA12 [Peripharal Expander]
303                <dd>Cabinet for peripheral extension, e.g. paper tape reader/puncher, PC05, card
304                    readers, etc.
306                <dt>DW08A [I/O Bus Converter]
307                <dd>Cabinet to connect "negative bus system" units. The "negative logic level" was used
308                    at the time of germanium transistors (PNP), for example the DF32 disk drive with
309                        fixed heads.
311                <dt>DW08E [I/O Bus Converter]
312                <dd>This plug-in for the smaller PDP-8e converts the PDP-8, -8i and -12 bus to the
313                    OMNIBUS system from the PDP-8e. Thus all 8e interfaces could be connected, e.g. the
314                        RK8E interface (Digitl RK05) or Plessey PM DD/8 disk drives.
316                <dt>BM812 [Memory Expansion Box]
317                <dd>Memory expansion box that is capable of expending either a PDP8i or PDP12
318                    from 8kB to 32kB with MM8e-stacks (like in the PDP-8e).
319        </dl>
321        <div class="desc-left auto-bildbreite borderless" style="margin-bottom: 0;">
322      <img src="/shared/photos/rechnertechnik/dec/talk-to-me.jpg" width="163" height="209" alt="Demo-12 Demoprogramm" />
323          <p class="bildtext small">So logs the PDP-12-demo program</p>
324        </div>
326        <p>This system is fully developed. This was a common approach at that time: At first the
327           computer was purchased in the basic version which was barely affordable. Afterwards
328           more options were installed step-by-step. That way the enormous acquisition costs
329           were distributed over several years and the computer was always up to date.<br>
330           We have very good programs [Demo-12 running on DIAL], which shows with extreme illustrative the performance of the computer. This includes an on-screen analog clock with real-time display and the game
331"SPACE WAR". Some of will be soon available on our special page [in working].
332    </p>
333        <div class="cols" style="clear:left;">
334        <div class="leftcol">
335        <p class="small">(Google-translation!):We have a PDP-12 price list from the year 1973, a period in which the PDP-12 was already an outdated model. Our fully-equipped computer was a PDP-12 LDP (Laboratory Data Processor), here specifically a "clinical lab12", sold at a price of DM 206.700. Most of the options listed above were built in. (In 1973 3,50DM corresponds to 1$).<br>
336        This computer was equipped with 4kB Memory Core. So one needs in adition a "Memory Extension Control" for 16.600 DM and a 4kB Memory Module for 25.100 DM. The price for the unimposing Peripheral Expander BA12 was 5.400 DM (equivalent to a midsize car) and "High-Speed Paper Tape Reader/Punch" incredible 16.200 DM.</div>
337        <div class="rightcol">
338        <p class="small">
340        A Disk Cartridge Drive RK05 where sold for DM 21.200, where one needs in addition the "Positive I/O Bus to Omnibus Converter" DW8E (6750 DM). Similarly is the Converter DW08A and the Cabinet AA50 for additional D/A Controller. The 3 plugged D/A modules were calculated with 1.680 DM per unit.
341        The memory expansion to 32K does not appear on the list, but the price for this option was about 50.000 DM including the controller.<br>
343        In the sum it is a staggering number of 387.690 DM, which is today corresponding about 500,000 € or 600.000 $!</p>
347<div class="clear">
350         <h3 id="lab8e">Lab-8e, PDP-8e</h3>
351        <div class="box left">
352                <img src="/shared/photos/rechnertechnik/dec/lab8e.jpg" width="400" height="461" alt="DEC LAB-8e" />
353        </div>
354        <div class="box center" style="min-width: 840px;">
355                <img src="/shared/photos/rechnertechnik/dec/pdp-8e,pannel.jpg" width="400" height="300" alt="PDP-8e operator panel" />
356        </div>
357    <div class="bildtext">
358            <p>The successor of the PDP-8i was the PDP-8e (1970). This computer came with an
359             internal bus system, so you could easily attach any peripherals using interface cards. This
360             feature made the "mini"-computer all-purpose. This computer type was offered with diverse
361             A/D- and D/A-converters and connection facilities as a laboratory computer for analogue
362             devices (shown in the picture). The peripherals are:</p>
363            <ul>
364                <li>VR 12 (oscilloscope display)</li>
365                <li>PC 04 (High speed paper tape reader/puncher)</li>
366                <li>3 x TU 56 (double tape drive)</li>
367                <li>A/D- and D/A-converter</li>
368            </ul>
369        </div>
370    <div class="box left clear-after">
371                <img src="/shared/photos/rechnertechnik/dec/8e-module.jpg" alt="8e-Module" width="400" height="175"/>
372                <p>The picture on the left shows a board for own peripheral interfaces. In this unit,
373                   bus amplifiers, etc. are already mounted. You could install your own ICs in front of
374                   them and connect them with Wire-Wrap or soldered wires.
375                   On the right is a typical module with a lot of ICs. Both modules are only partially
376                   visible.
377                </p>
378    </div>
381 <h3 id="nova-en">Data General: NOVA 2</h3>
383   <div class="box left">
384      <img src="/shared/photos/rechnertechnik/nova2.jpg" width="400" height="561" alt="Data General: NOVA 2" />
385<p>     Edson de Castro was responsible for product management at DEC and was intent
386on developing a 16-bit computer with a processor that would fit on a single
387printed circuit board. But Ken Olson, the founder of DEC, wasn't
388supportive. So de Castro left DEC in 1968 together with three other
389hardware engineers to found his own company in a vacant barber's shop:
390<b>Data General Corporation </b>(Massachusetts, USA).<br>
392Already in 1969 the first 16-bit computer in the <b>"NOVA" </b>series was ready
393for the market. Thanks to the simpler production method (no wire wrapping,
394only two boards + memory boards etc.) the basic version was quite inexpensive
395at $4000. However, this basic model alone wasn't really that useful, and
396after extending the computer the total price was substantially higher.
397The Nova computer was advertised as "the best small computer in the world".
398At this time, DEC was still building the PDP-8/I and the PDP-12, which
399required lots of very small flip-chip-modules. <br>
401The successor model (available in 1973), the<b> NOVA 2</b>, was simplified even
402further, and the increased chip density made it possible to have the whole
403processor together with the control logic for slow peripheral devices
404(teletype, paper tape puncher and reader) one single board. Our Nova is a
405NOVA 2/10 model with slots for 10 boards, and therefore enough space for
406quite a few device controllers and memory extensions.<br>
409From today's perspective, the rather huge boards (15x15 inch,
410nicknamed "circuit graveyards in baking tray size") do have disadvantages:
411any kind of repair is very difficult, because it is not possible to pin down
412a malfunction by exchanging small boards.<br>
414The NOVA shown in the picture is from a university. It is equipped with
415two harddisk drives, one twin floppy drive (8" disks!), one teletype,
416one high-speed paper tape punch reader and one punch card reader (not in
417the picture). Later on a terminal was added, which extended the computer
418to a comfortably usable system.</p>
420The details are better visible in a larger photo: <a  class="popup" href="/shared/photos/rechnertechnik/nova-detail.jpg">NOVA 2 with terminal</a><br>
422          <p class="bildtext small">
423Hardware configuration, from top to bottom:<br>
426<dd>Paper tape punch reader (mostly used for testing programs included with
427  every delivered system)
428<dd>Twin disk drive for 8-inch floppy disks, Model 6032
429<dd>CPU with core memory, 32 KB, access time 0.8 us
430<dd>Two hard-disk drives with removable cartridges, Series 30. Capacity
431  1.200.000 16-bit words, or 2.4 MB.
432<dd>Disk Cartridge System 4047, necessary to connect the second disk
433<dd>Terminal "DASHER 1", Model 6052 by Data General, on the right hand side
435 </div>
438    <h3 id="wang2200">WANG 2200 with bulky peripheral hardware</h3>
439    <p>Next, the first system that looks like today's computer is presented: <a class="go" href="/en/devices/wang2200.php">WANG 2200</a>, year of manufacture 1973. This computer, with so many peripheral devices, is probably unique in Germany. The peripherals: paper tape reader, punch card reader,  triple 8-inch disc drive, hard disc system with 38cm diameter disks (the device weights 100kg and cost 24000 DM, but only holdy 5MB), special BASIC-language keyboard, etc.</p>
440    <p>WANG quickly recognized that the future of computers needed screens. However the concurrent HP
441    computers had only a single-line LED display until 1975.</p>
443    <div class="box center">
444       <a href="/en/devices/wang2200.php" name="backlink-wang2200"><img src="/shared/photos/rechnertechnik/wang2200.jpg" width="592" height="402" alt="Wang 2200" /></a>
445    </div>
447    <p>The first personal computer was also build by WANG: the PCS II (1975). The first PC that was affordable for everybody was the PET 2001 from Commodore. It came on the market in 1977 and was as cheap as today's PCs, but had 8kB and had decent applications. Many more home computers followed, the market got out of hand and therewith this collection of computers ends.</p>
449    <p> See further details at <br>
450         <a class="go" href="/en/details2.php" title="Details 2"> the tabular overview of
451     mid range data processing equipment and proffessional early computers</a>.</p>
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