Exelbasic + (Plus)

September 2, 2018

exelbasicplusSome time ago, I acquired an Exeltel VX. Like any other flavour of Exelvisions computers (the EXL100 and the other Exeltels) it has no built-in programming language (in case of the Exeltel VXs this would have been a lesser problem anyway as it wants to be a Videotex terminal). However, if you want to load anything from a cassette (or a floppy disk or a battery-buffered RAM) you need your Basic. Exelvision delivered one with every EXL100, the Exelbasic.

In order not to have to borrow an Exelbasic from a friend (hi, cobrakai!), I bought one from Ebay (which does not appear that often as one wants, especially for a sane price). What I ended up with was not an ordinary Exelbasic, but the improved Exelbasic + (Plus) which I did not even know existed. Instead of a measly 200 pages of (French) manual, you have a 300 page one (also French). I am happy!



Intergraph Clipper Workstations

July 30, 2018

Just as an addendum to the last post, here is a list of all the Intergraph Interpro workstation models with a Clipper CPU.

We start with the earliest models:

Model Year of Introduction CPU
32C 1986 C100
120 1988 C100
125 1989 C100
220 1988 C100
225 1989 C100
340 1988 C100
360 1988 C100

From about 1989, Intergraph introduces a systematic naming scheme. It is described as a comment in the MAME emulator code in the Reference section. It follows an ABCD format:

  • A: case type (2=desktop, 6=minicase)
  • B: CPU type (0=C300, 4=C4T, 6=C400?, 7/8/5 = C400I)
  • C: graphics type (0=none, 3/5=GT, 4=EDGE-1, 8 = EDGE-2)
  • D: usually 0, 6xxx systems have 5, 7 and 9 options (backplane type?)

Graphics type 3 is for GT graphics fitted to a 2xxx system, and type 5 when fitted to a 6xxx system.

This scheme allows you, in principle, to generate all possible model numbers. However, of course, the CPUs and the graphic options developed over time and older options were not necessarily offered later on.

These are the models that I could find in the literature:

Model Year of Introduction CPU
2020 1991 C300
2430 1992 C400
2730 1993 C400
2830 1994? C400
3050 1989 C300
3070 1989 C300
6040 1990 C300
6080 1990 C300
6240 1990 C300
6280 1990 C300
6450 1992 C400
6480 1992 C400
6750 1993 C400
6780 1993 C400
6850 1993 C400
6880 1993 C400

Now, if you read the above scheme carefully and compared it to the list above, you can see that the scheme is missing some values. First, there seems to be a short-lived “3” case type. Second, there is an unkown CPU type “2”, obviously also a C300. Third, two unknown graphics options “0” and “7”.

Finally, I assume that the CPU type “8” is a C400 that runs on 50 MHz instead of the 40 MHz of the “7” models.


Intergraph 2700 Series Workstation

July 29, 2018

I bought on Ebay a 1993 workstation from a manufacturer

  1. you might not think about immediately regarding classical workstations
  2. that still exists today

The manufacturer is Intergraph, a company that started in 1969 on engineering for government agencies. It became one of the leading CAD/CAM suppliers in the 1990s, and stopped making hardware in 2000. Today, Intergraph is a 4000 people company working in the Geographical Information Systems area.

The workstation, a “2700 Series” model, is interesting mainly from a CPU point of view. It uses the last model of the “Clipper” family of CPUs (and not an ordinary PC processor, SPARC, MIPS, PA-RISC, or POWER chip, these are for common people :-).

The following paragraphs contain mainly passages from the [Wikipedia entry]. Clipper CPUs started their live when Fairchild decided to develop a 32-bit RISC CPU that was available from 1986. The first model was called C100. In 1987 Schlumberger, who owned Fairchild from 1979 on, sold Fairchild to National Semiconductor in 1987. They also sold the Clipper technology to the biggest customer of this technology, Intergraph. National Semiconductor would probably not be interested in Clipper, anyway, because they had their own 32-bit CPU the NS320xx family (in fact, it was the first 32-bit general-purpose microprocessor). It was developed earlier, and it was not RISC (but it was also not commcercially successful even if the list of computers incorporating this CPU is impressively large).

So in 1988 Intergraph developed a new model of the Clipper family, the C300. In 1990, finally, the last model of the family, the C400 was released. It was the first processor to integrate both architectural techniques, superscalar and superpipelined operations. Superscalar instruction dispatch means executing more than one operation at a time. Superpipelined operation means that some of the stages of a pipeline are broken up into smaller sub-stages in order to increase the performance. As a consequence, in 1990 the C400 with its 33 MIPs and 9 MFLOPs compared favourably to its competitors, e.g. early SPARC or POWER processors.

The Clipper architecture used a simplified instruction set compared to earlier CISC architectures, but it did incorporate some more complicated instructions than were present in other contemporary RISC processors. These instructions were implemented in a so-called Macro Instruction ROM within the Clipper CPU. This scheme allowed the Clipper to have somewhat higher code density than other RISC CPUs.

Unlike many other microprocessors, the Clipper processors were sets of several distinct chips. The C400 consists of four basic units: an integer CPU, an FPU, an MMU, and a cache unit, but the MMU and cache unit were combined into one CAMMU chip. Therefore, the C400 consists of 3 separate chips. Funnily, the largest chip is the CAMMU.

The strength of Intergraph (short for Interactive Graphics) computers was always graphics. Not so much the 3D graphics for VR and animated movies, but the 2D and 3D graphics for CAD/CAM-like applications. Therefore, also their workstations came with good graphics capabilities. My workstation even has a 2-display graphics card where everythings seems to exist twice: 2 x 2 MB Video RAM, 2 RAMDACS (yes, this was the time when RAMDACs were separate chips).

Intergraph workstations came for a long time in one of three combinations and names:

  • InterPro: desktop form factor plus separate display
  • InterAct: tower form factor plus two displays integrated into a digitalisation desk
  • InterView: tower form factor for a nearby digitalisation desk

According to my favorite market resource, at least in Germany, 3 different models of the 2730 desktop workstation were sold:

  • InterPro 2730-112: Single 19″ display
  • InterPro 2730-122: Double display
  • InterPro 2730-352: Single 21″ display

So, what model do I probably have? Well, after reviewing the above models and knowing the configuration of my workstation (32 MB RAM, 426 MB HDD, double display card), it is probably a InterPro 2730-122, and a not upgraded one.

You have probably noticed that I do not have pictures from a running workstation. That is, because I do not have a monitor yet. One would hope that any 13W3 display could do, but probably I am way to optimistic about that.

Like Sun’s, also Intergraph had a Forth-based diagnostics tool accessible at the firmware level. As I am a big fan of Forth, I am curious to see what one can do with this one.

According to [Wikipedia], “Fairchild promoted the CLIX operating system, a version of UNIX System V, for use with the Clipper. Intergraph adopted CLIX for its Clipper-based systems and continued to develop it; this was the only operating system available for those systems.” Later on, Intergraph ported Windows NT to Clipper computers, and even demonstrated such systems. However, Intergraph cancelled this project before its release. However, there is a 3.5″ floppy disk in my disk drive and it’s labelled “NT 3.5.1 21/21”. I’m very curious what this means. As soon as I get a monitor, I will tell you…

The last Clipper-based computer was the 2830 model which (I assume) is a 2730 with a 50 MHz (instead of a 40 MHz) C400. In 1995, Intergraph gave up this line of computers and sold exclusively x86 systems with Windows NT or Solaris.

The outer design of the workstation is quite standard and boring:



However, the build quality and the industrial design of the machine is really good. If we remove the heavy gauge steel cover by removing three screws we see a nicely laid out interior:


The right third is the PSU- The PCB on the bottom is the graphics card. Here is it in more detail:


The top part of the interior is a cage with the HDD and the FDD. It is so well designed that you can swivel the entire cage up after removing a thumb screw:


And underneath you find the SIMM slots to the left and the CPU on the right:


Four slots filled with 8 MB of RAM each, and another 12 slots empty. The chip with the big heat spreader (the one with the hole) is the CAMMU, the other two are CPU and FPU. If you want to see how the chips look like underneath: la voila!

Technical Data

Manufacturer: Intergraph
Model: 2700 Series
Introduced in: 1993
Initial price: ???
CPU: Intergraph Clipper C4 (a.k.a. C400) @40 MHz
RAM: 32 MB (128 MB max)
HDD: 426 MB (externally max: 9.4 GB)
FDD: 3.5″, 1.44 MB
Graphics: “GT+ Graphics”
Colors: 256
Interfaces: RS232, parallel, Ethernet, SCSI, keyboard, mouse, plotter, screen (13W3)


Tektronix Smalltalk Workstations (4400 and 4300 Series)

July 20, 2018

Tektronix (also known as “Tek”) is very well known for their manufacturing test and measurement devices such as oscilloscopes, logic analyzers, and video and mobile test protocol equipment. Lesser known are their computer models. Today I want to dig into the Tektronix family of Unix workstations that support a special feature: the programming language Smalltalk.

I am a big fan of Smalltalk even if this language today plays hardly a significant role. Tektronix was heavily involved in the commercialisation of Smalltalk; in fact they provided the first commercial version of Smalltalk.

What is Smalltalk?

As Smalltalk is currently such an exotic language (it was quite a niche language even at its best times), we should probably have a short look on this programming language.

Smalltalk is an object-oriented, dynamically typed, reflective programming language. The typical implementation uses a small (hardware-dependent) Virtual Machine that interprets bytecode. The major part of Smalltalk is implemented as bytecode (in this sense it is very similar to Forth). The typical Smalltalk system includes the Graphical Development Environment (using its own GUI if necessary), the runtime environment, and the Smalltalk-to-bytecode compiler, all written in Smalltalk. Also, all sources exist live in the system, i.e. you can read them, and you can change them on the spot. As a result, Smalltalk is probably the easiest language if you intend to shoot yourself in your foot, e.g. by editing the compiler that compiles the compiler code 🙂 You typically save a Smalltalk system by making a copy of the entire state of the Virtual Machine, including code, variable contents, the lot. Therefore, if you shoot yourself in the foot, you simply reload the last copy of the working Smalltalk system.


Picture of how Smalltalk typically looked like in the 80s

Smalltalk is also a language that takes object-orientation very literally. Conceptually, the statement “1 + 2” is interpreted by Smalltalk as: there is an object “1” that is sent a message consisting of two elements, a “+” procedure name and a parameter “2”. Lesser languages aim to translate object-oriented code into a procedural intermediary language (like C++ was originally a pre-processor for C), but that’s not the Smalltalk way (I know that people knowing modern Smalltalk will now complain and try to explain that nowadays Smalltalk is able to e.g. directly compile into objectcode, but as we will talk about Smalltalk in the 80s, my explanation comes very close to the reality back then).

Smalltalk was developed from 1969 by Xerox PARC. In 1980 Xerox PARC made an attempt to interest other companies in creating commercial versions of Smalltalk. One of the companies that answered to this call was Tektronix.

The first development generation (1980-1981) of Tektronix’ Smalltalk system was a single-board 68000 system connected first to a Tektronix 4025 raster graphics terminal, later on to a directly connected bit-mapped display. The Smalltalk base system was implemented using their own Pascal compiler (cross-compiled on DECsystem 10/20 computers).


Smalltalk on the Magnolia Workstation

The second development generation (Late 1980 -1981) ran on the “Magnolia” workstation. The architecture of Magnolia was very much along the lines with what we today identify as an early workstation: 68000 CPU, bit-mapped display, Unix-like OS, C compiler, harddisk, mouse. As the performance of the first Smalltalk system (like every other Smalltalk implementation apart from the original Xerox ones) on the single-board system was dismal, Tektronix changed the execution mechanism completely and ended up in a well-performing system.

This success inspired Tektronix to come up with a Smalltalk workstation product, code named “Pegasus”. It ended up in the model 4404 which was 68010-based and was marketed as an “AI machine”, featuring both Smalltalk and Lisp (as an option). As Motorola was not shipping yet a 68k MMU, a discrete MMU had to be designed as virtual memory support was considered essential for supporting Smalltalk and Lisp.

The third generation Tektronix Smalltalk was developed in 1985-86 for the 68020-based 4405/4406 models. It first shipped with the 4405/4406 in January 1986.

The final major revision of Tektronix Smalltalk was done for the 4317 model that was sold from 1987.

Fortunately, the history of Smalltalk at Tektronix is extensively documented (as an entry I suggest the “Tektronix Smalltalk Document Archive”, see the references).

As I am such a big fan of Smalltalk, I really would like to own a Tektronix Smalltalk workstation (a currenty unfulfilled desire). So, if you know one that needs a new owner…

Later workstation models did not came with Smalltalk, and Tektronix also made other workstation families. The Tektronix 6130 workstation (from 1984) had a NS32016 32-bit CPU, the XD88 family (from 1989) a Motorola 8800 CPU.

Please find in the following a list of the technical data of all 4400 and 4300 series workstations. Because it was little additional effort, I listed also the data of some 4300 series models that did not have Smalltalk.

4400 Series Models (Smalltalk)


CPU: 68010@10 MHz + NS32081 FPU
RAM: 1 – 4 MB
Resolution: 640 x 480
CRT: 13″
HDD: 45 MB
FDD: 320 kB
Interfaces: RS232C, LAN, SCSI, centronics
OS: Unix-like OS
Initial date: 1984
Initial price: $14950


CPU: 68020@16 MHz + 68881 co-processor
RAM: 1 – 5 MB
Resolution: 640 x 480
CRT: 13″
HDD: 45 MB
FDD: 320 kB
Interfaces: RS232C, LAN, SCSI, centronics
OS: Unix-like OS
Initial date: 1985
Initial price: $14950


CPU: 68020@16 MHz + 68881 co-processor
RAM: 2 – 6 MB
Resolution: 1280 x 1024
CRT: 19″
HDD: 90 MB
FDD: 320 kB
Interfaces: RS232C, LAN, SCSI, centronics
OS: Unix-like OS
Initial date: 1985
Initial price: $23950

4300 Series Models

2D Terminals (no Smalltalk)


This family was the workstation variant of the 4320 workstation family. The models differ only in the grahics resolution.
4224: Resolution: 1024 x 768
4225: Resolution: 1280 x 1024
Graphics Processor: 68020@16.0 MHz
Colors: 256
Graphics RAM: 4 – 8 MB
CRT: 16 or 19″, 60 Hz
Interfaces: 3 * RS232C, LAN (IEEE 802.3), 2 * RGB, SCSI, color printer
Initial date: 1987
Initial price: $12950-$37500

3D Terminals (no Smalltalk)

This family was the terminal variant of the 4230 workstation family. The models differ only in number of colors.
4235: colors: 16/256
4236: colors: 256
4237: colors: 4096/16.7M
Graphics Processor: 68020@16.7 MHz
Resolution: 1280 x 1024
Graphics RAM: 4 – 52 MB
CRT: 16 or 19″, 60 Hz
Interfaces: 3 * RS232C, LAN (IEEE 802.3), 2 * RGB, color printer
Initial date: 1987
Initial price: $23500-$37500

2D Workstations, entry level (Smalltalk)


The family is the entry line of 4300 series workstations. Apart from not having too much dedicated graphics hardware (it seems), they have a built-in Smalltalk environment.
CPU: 68020@16.7 MHz + 68881 co-processor
HDD: 86 MB
FDD: 1.2 MB
Interfaces: RS232C, LAN, SCSI, centronics
OS: UTek (Tektronix Unix with X Windows)
Initial date: 1987
Initial price: $9995-$18950
RAM: 5 – 13 MB
Resolution: 640 x 480
Colors: monochrome
CRT: 13″
RAM: 4 – 12 MB
Resolution: 1376 x 1024
Colors: 16 grayscale levels
CRT: 19″
RAM: 4 – 12 MB
Resolution: 1376 x 1024
Colors: 16/4096
CRT: 19″

2D Workstations, medium level (no Smalltalk)

This family was the workstation variant of the 4220 terminal family. The models differ only in the grahics resolution.
4324: Resolution: 1024 x 768
4325: Resolution: 1280 x 1024
CPU: 68020@20 MHz + 68881 co-processor
RAM: 4 – 12 MB
Graphics Processor: 68020@16.0 MHz
Colors: 256
Graphics RAM: 4 – 8 MB
CRT: 16 or 19″, 60 Hz
HDD: 86 MB
FDD: 1.2 MB
Interfaces: 2 * RS232C, LAN (IEEE 802.3), 2 * RGB, SCSI, color printer
OS: UTek (Tektronix Unix with X Windows)
Initial date: 1987
Initial price: $23500-$37500

3D Workstations (no Smalltalk)


This family was the workstation variant of the 4230 terminal family. The models differ only in number of colors.
4335: colors: 16/256
4336: colors: 256
4337: colors: 4096/16.7M
CPU: 68020@20 MHz + 68881 co-processor
RAM: 4 – 12 MB
Graphics Processor: 68020@16.7 MHz
Resolution: 1280 x 1024
Graphics RAM: 4 – 52 MB
CRT: 16 or 19″, 60 Hz
HDD: 86 MB
FDD: 1.2 MB
Interfaces: 2 * RS232C, LAN (IEEE 802.3), 2 * RGB, SCSI, color printer
OS: UTek (Tektronix Unix with X Windows)
Initial date: 1987
Initial price: $37500-$51500

Applications Processor (no Smalltalk)


This device completed the terminals to their workstation variant. It therefore included the CPU and co-processor, the CPU RAM, the HDD, and the operating system.
Initial date: 1987
Initial price: $14950


Tektronix 4300 Series Catalog (1988)

Tektronix Smalltalk Document Archive

Roger D. Bates: MAGNOLIA – A Single User System. Design and Implementation Plan. September 1980.

Paul McCullough, “Implementing the Smalltalk-80 System: The Tektronix Experience,” in Smalltalk.80: Bits of History, Words of Advice, Glenn Krasner, ed., pp. 59-78, Addison-Wesley, 1983.

David Computer PROFI 203

June 12, 2018

As you might know by now I like rare and obscure computers you will not find much about from other sources in the Internet. But, at the same time, that’s also a problem for me if I want to write a new entry to this blog: I have to find out about another rare, strange computer, hopefully standing out from the waste mass of CP/M machines and PC compatibles. This task seems to get increasingly more difficult over time (maybe naturally so). If *you* have a proposal in this direction, go ahead and write a comment…

However, I was able to compile a short list of interesting contestants, and today I want to start to write about the first one. Of course, I could research the computer, and write an entry when I’m done, but why not doing it in the form of a logbook, extending the entry as I learn more about it. Maybe, there are some folks out there who would want to accompany me along the way. So, here we go.

June 12th, 2018

Today I learned about a model that is *really* obscure, almost a yeti of a computer. There is basically one entry in old-computers.com which we can use as a starting point. The model is called “PROFI 203” (Professional 203 if you like) from a company called “David Computer”. Never heard of any of that? Me neither. According to the mentioned entry, it is a 1983 machine from Germany with a Fairchild 9445 CPU.

A *what* CPU? Apparently, this was a Data General NOVA 3 computer-on-a-chip (running 10 times faster than the original NOVA 3) made at Fairchild, a successor to Fairchilds 9440 CPU which emulated the NOVA 2. Now, some of you might recognize the names Data General and NOVA because they play an important role in the popular 1981 non-fiction book “The Soul of a New Machine” by Tracy Kidder on the development of the Data General Eclipse MV/8000. The NOVA was a 16-bit computer, therefore the 9445 was a 16-bit CPU. As it can be expected, Data General was not pleased about the possibility of having competition by a code-compatible CPU and they sued Fairchild for many years. Bottomline: the 94XX cpu family was not a success. But it is very interesting to me because this is quite an exotic beast. First productions of the 9445 were delivered late in 1981. Initially, the 9445 ran at 16 MHz, later versions also on 20 MHz and 24 MHz. It could address 128 kB of RAM directly.

The old-computer.com entry contains a photo (the only photo I ever found so far):

Quite a beast of a computer. It seems that you have a small-refrigerator-in-a-desk form factor, with a printer on the top, and a display and keyboard in front of the user.

The entry does not tell us much more, only that it uses a “MIDOS” operating system, and that is has a monochrome display, RS232, IEEE 488, and Monitor interfaces, as well as one “or several” 5.25” disk drives.

One (of two) comments says “I just posted a bunch of information about the dAVID Computer, designed and built in Kitchener, Ontario, Canada in the early 1980’s. However, I got an error from this site when I submitted it. If there’s interest I can try again.” Well, Jack, the unresponsiveness of old-computers.com made me start this blog in 2009 🙂 (J.C., if you read this, *I* would be very interested…).

And that’s it what I know for now. When asking Google for “David Computer” “profi 203”, I get basically one other hit, namely a very brief 1983 mention in the German computer industry newspaper “Computerwoche” (who, thankfully, have their entire archive since 1974 online). Here is the translated text:

“Their family 200 with over 20 different models is presented by the David Computer GmbH, Stuttgart, at the Fair in Cologne.

The smallest member of the family is the upward compatible 16-bit micro computer profi 203. In the standard configuration the model has 128 kB RAM, two floppy disks drives with a capacity of 512 kB each, a screen, and a printer. Maximally, the profi 203 could be fitted with 356 kB RAM and a 40 MB hard disk drive. In the multi-user mode up to four screens can be connected. The price for the standard configuration is about 20’000 DM [which would be about 21’000 $ in 2018]. The maximum configuration of the largest model of the family, the profi 230 is 1024 kB RAM, 600 MB hard disk space and 24 screen interfaces. […]

David Computer also offers the software package Intext/M for their micro computer, a program with integrated data and text processing. In addition, the Stuttgart company will demonstrate the usage of Teletex and Electronic Mail using the profi 203.”

And, then, the best part: the address of the company. It is called “David Computer GmbH” and it is about 2km from my home. I could walk there if I could also move back 35 years in time (no, the company does not exist there any more). My jaw drops, this is a nice  coincidence in an area where most players used to sit in the U.S.

So, that’s all Google has to offer using these keywords. But, there is another dependable source of information if the computer was offered in Germany: my beloved CC Computerarchiv. And, low and behold, in the June of 1983 issue of the office equipment part, there it is:

The model 203/20, priced at 30’521 DM, with a 10 MB hdd, a terminal, and one 1.6 MB floppy disk drive. Another 5530 DM for an additional text terminal. The model 230 for a mere 37’940 DM with 256 kB RAM, and an additional 25’368 DM for 2 * 14 MB hdds. All prices for any option you can have.

No entry in subsequent issues. David Computer seem to disappear from the market after 1983.

So, what remaining leads can we follow?

  • we can try to find out more about the David Computer GmbH (especially given that I am living in the area where they used to be)
  • we can try to find out whether this computer is also known under another name (the Fairchild 9445 CPU was used only in a few computers)
  • we can try to find more about MIDOS, the operating system
  • we can try to find out more about Intext/M

And that’s what I will do in the course of the next days, so stay connected.

June 16th, 2018

Ok, I hate it when a mystery clears up so quickly. Let’s start with the leads that did not lead anywhere. Intext/M, not a thing outside the 203 computer. MIDOS, the same.

What actually tells us something are official information on the David Computer GmbH. There is an official registry portal of all German states that registers by and large all companies in Germany. You can ask it even for closed companies. You have to pay if you want to have detailed information, but some fields are free. So there was a “David-Computer Vertriebs-GmbH ” from 1977 to 1991. That’s probably the one we know of. The entry specifies also the Predecessor of this company, the “DDC Computer Vertriebs-GmbH”. And if we look into CC Computerarchiv, we immediately get a model “203” and “230” from “DDC” in 1982, with the same data and similar prices. But that’s not all, DDC is represented in all issues of CC Computerarchiv from 1976 on (although with different models). But the last entry for DDC is in 1982, and the only one for David Computer in 1983. So where did these computers go after that date? The solution again comes from the companies registry. From 1983 until 1991 there is a company called “SynTec System- und Software-Entwicklung GmbH” whose one predecessor was the “David Computer Systeme GmbH”. The other predecessor was the “Ericsson Information Systems Vertriebspartner GmbH” (Ericsson Information System Distribution Partner, Inc.). Ok, So Ericsson had a hand in this game. And, what do you know?, from 1984 the company “Ericsson Vertriebspartner” (not to be confused with Ericsson, who has an entry on its own with different models) is represented in CC Computerarchiv with the models 203 and 230. This continues in 1985. In 1986, three more models appear, the 240, 250, and 260. The same in 1987 and 1988. From 1989, there is no more “Ericsson Vertriebspartner” and no more models 203-250 represented.

Now, if we search for “Ericsson” and “203”, we learn that the family of computers is  called “Eritron” (probably after 1983). Using this new name, we can find more information on this computer system which we will do in a few days. Stay connected!

June 24th, 2018

So, let’s see what we can find out about the Eritron line of computers. There is a thread in a C64 forum (in German) on the machine, together with photos of components. The guy taking the photos (in another man’s garage) could figure out a PCB with some AMD Am2903 (4-bit) Bit-Slice chips and claims this would be the CPU. Hmm, I’m not sure on that.

Apart from the additional models 240, 250, and 260, there were also the models ET1 and ET1a (ET stands for Eritron Tower). An in this database, the CPU for the ET1 is stated as 9945. That’s the second mentioning of the 9945, but there are also not more.

What I found mentioned several times is that the 200 series used MULTIBUS as a bus system. And that the 200 series later on had a software product that ventured into “Computer-aided Translation”.

But, again, that’s it. No pictures except the one. CPU probably a Fairchild 9445. Main application area Word Processing for companies and institutions. Users sat on terminals connected to the servers via serial line. The business could keep up for some years until it was probably taken over by PCs. I think I have reached the end of Internet research possibilities for this model. If I ever find out more, I’ll post it here.


Pick-Master – A Soviet Spectrum Clone?

May 10, 2018

From time to time I like to acquire computers that a so obscure that the Internet cannot tell you what they are. You have to get physical access and examine them (and then describe them for the Internet :-).

Update: I found out more about this computer. See the reveal at the end.

So I bought an allegedly “Soviet Spectrum Clone” from Ebay called “Pick-Master”.


The (rattly but) real keyboard is all-latin and has the original Spectrum key settings on some of the keys (even if the “J.J.” and “J.F.” keys seem quite strange). The grey metal top plate proudly tells you this is a “ZX-Spectrum original system” with a Z-80A CPU, Basic, and 48 kB RAM, and that it “run(s) with any tape recorder and TV set”. Compared to an original ZX Spectrum, the case is huge.


The bottom is boring, but has a paper sticker that seems to bear a serial number “00243”.


The bottom features two fold-out legs, ok, that’s nice.

The back


has 4 interfaces, all marked in latin:


RGB seems clear, JOY is probably joystick, DC5V seems clear enough. “TYPE” though: very strange. Maybe a typewriter interface? Now, the elephant in the room, of course, are connectors. I never saw these types of connectors. Each one has 8 pins.

So, this was the situation before I bought the thing. Google knows nothing at all about a “Pick-Master”. There is no photo that ressembles this thing. I am excited allthough I know that the number of Eastern Block spectrum clones are legion, that I cannot read kyrillic and that there are currently not enough resources in English on this topic.

Ok, what can we tell from the inside of our computer? This is our computer opened:


Now it is clear why the computer is so large: the functional parts are ordered around the keyboard, not underneath.

The build quality is good, the parts look hand-soldered. No helpful markings on the board. The keyboard baseplate is probably not designed for this model, it looks as if it has space for an additional row of function keys on the top and as if it was cut at the top right corner in order to give space to some components on this PCB.

Here is a picture from the interesting part of the PCB:


We find:

  • the CPU: a (Z)80A MME9212. This is a Soviet version of the Zilog Z80A. MME might hint to being manufactured in Erfurt, GDR (i.e. at that time East-Germany). This seems to be an “export version” whatever that means. Maybe exported to the Soviet Union.
  • 8 * KP565PY5 64 kbit chips
  • KA1515XM1: a Russian ULA chip
  • KP563PE2: PROM 32kx8 (maybe 32 kB?)

Ok, so this is definitively a Soviet Block Spectrum. Maybe designed to be exported to the West because the top is so much advertising the machine.

In every case a very, very rare machine, and an interesting one, too.

Update: Thanks to a very resourceful native Russian speaker (Hi, Anastasiia!) we found out more about this machine. Spoiler alert: it is still very rare and this variant is not yet described. So, what do we have here?

According to http://zxbyte.ru/pik.htm, this is basically a Soviet “Peak” computer, made by the “Terminal” (Терминал) company in Vinnitsa, Ukraine. If you are as able to read Russian as I am, here is the Google Translate link: https://translate.google.de/translate?hl=de&sl=ru&tl=en&u=http%3A%2F%2Fzxbyte.ru%2Fpik.htm

The Russian model name is “Пик”, which translates to “peak”. The manufacturer was known “in the whole (Sovjet) Union” for its – terminals (hence the imaginative company name). So, still an industrial manufacturer 🙂

According to the above web page it has a Kempston joystick interface (which is to be expected). The “TYPE” interface I was wondering about is a – tape interface. Maybe a translation typo? The connectors are all the same, so there is the danger that you put e.g. the power cable into the joystick interface, ugh…

The ROM seems to contain a Sowjet standard image of the Spectrum software from Didaktik Skalica, copyrighted 1989. It was used also in other Sowjet Spectrum clones. The model itself seems to be made around 1992.

Now the best part: if you compare the pictures of the computer on the Russian page with mine you can see:

  • the Russian version has the model name and the “advertisment text” in Russian, mine in English – so I seem to have really some sort of meant-for-the-export-to-the-West version. Whether a Spectrum clone could still be sold in the West in 1992 is very questionable, 10 years after its introduction. The model name on my version is “PiCK-MASTER”. Maybe a play on words with the original PIK name…
  • the Russian version has a socketed Goldstar Z80A in a plastic case. My version has an soldered Sovjet Z80A copy in a ceramic case.
  • My version has a small daughter PCB in the top right corner which does not exist in the Russian model. I have no clue on the function of this “patch”.
  • The Russian model has the serial number 168, mine has 243. I have no clue what this means.
  • Either my version was earlier (and they have a different serial number range for both models). They started by trying to market these to Western markets, did not come far, and switched back to the domestic market. As they could not get Sovjet Z80A clones any longer, they switched to Western versions. They found some problem, made a patch PCB and added that into the machine, and in later versions, they changed the main PCB and incorporated the patch on the mainboard. Or, my version was later (maybe the serial number range was consecutive), they added some hardware in order to cope with e.g. Western TV sets (therefore the patch PCB). The Goldstar CPU could have been a replacement to the original CPU at a later date.

All in all, I am very pleased. Thanks to Anastasiia, I could find out who made this computer and when. It is an unknown export variant of a very rare Sovjet Spectrum clone. And, I agree to the author of the Russian page on the Peak, “one of the most beautiful clones of the Spectrum“.

Exeltel and Exelrecorder

May 10, 2018

A pro tip for people trying to connect an Exelvision or Amper Exeltel to a Exelrecorder: use a 8-prong DIN cable (270 degrees). If you don’t, you might wonder why the damn thing isn’t saving or loading :-). Okok, I’ll explain. The Exeltel is an interesting (by and large unsuccesful) 8-bit computer that incorporates a modem (and therefore, a telefone connection) for different purposes. One of these purposes was the use as an answering machine. Due to the lack of compute power and digital storage capabilities (8 bit, we remember) this means that you want to record to a cassette tape (using analogue audio, of course). In order to do that the computer has to be able to remote control the cassette recorder. In order to do that you need: a) a cassette recorder that can be remotely controlled, and b) a cable that provides the additional lines to control the recorder. That’s why there is an accessory for the Exeltel: the Exelrecorder.

There was also a quite standard cassette recorder (called the K7) for the predecessor of the Exeltel, the EXL100. This recorder and the EXL100 use a standard 5-prong audio DIN cable because there was no remote control need for that machine. The Exeltel and the Exelrecorder, though, need an 8-prong DIN cable for the additional functionality. Now, my problem was that I had an Exeltel and an Exelrecorder, but no cable. I tried it with a 5-prong cable, but the Exelrecorder would not start recording or playing. Only when I bought the 8-prong version, everything worked. If you have the same problem you’ll find that 5-prong DIN cables are hard to come by today, but an 8-prong one reduces your choice of shops to a very small number.

GRiD “Convertible” Model 2270

April 29, 2018


GRiD was a legendary company that existed from 1979. In 1988 it was purchased by Tandy Corporation, whose computer manufacturing division in turn was then bought by AST Research in 1993, which in turn was bought by Samsung in 1996. It was always a company that targeted not the mass market, but niche markets where the price of a product was less important than the technical features. As a result, GRiD had e.g.

  • the firstclamshell-design portable computer (GRiD COMPASS, 1982)
  • use of the Intel 8086 and 8087 floating-point co-processor in
  • a commercial productnotebook that had a built
  • in hard drive (GRiDCASE 12xx, 1984)pen-based tablet computer (GRiDP
  • AD 1900, 1989)portable to have a built-in pointing device (GRiDCASE 1550sx, 1990)

GRiD mainly sold solid computers to audiences with special needs, e.g. the military, or NASA.

Another one of their “firsts” was the first convertible computer, i.e. a model that could be used as a tablet and as a notebook computer: the two models 2260 and 2270 from 1992.

Except in the recent time there weren’t that many convertibles out there because a convertible needs a market demand for a tablet computer that then also shall be used as a notebook as writing text a lot is a pain on a tablet. Pen-based tablets were a hot topic in the first half of the 1990s. Afterwards, pen computing by and large vanished from the list of hype topics (with the notable exception of pen-based PDAs from 1996 to the early 2000s). Only with the (re-)advent of touchscreen-based User Interfaces by Apple’s iPhone from 2007, tablets re-appeared from 2009, this time without needing a pen. With the new interests in tablet computers, also convertibles re-appeared on the market.

Back to the GRiD 2270. In 1992, GRiD presented the convertible computer in two models (2660, 2670) that differed only internally. Both models were PCs that offered both a tablet mode using a Wacom pen subsystem and a notebook mode with a compact, but full-fledged keyboard. Both models had a 9.5″ 64 gray levels VGA LCD, a built-in HDD, and 4 MB of RAM. An external FDD could be connected to the parallel port. The 2260 used a 80386SL processor running at 25 MHz, the 2270 a 80486SL processor running also at 25 MHz.

There is a whole slough of names under which the two models are known. To the best of my research, these are officially the GRiD Model 2260 and 2270, respectively. My (German) manual to the 2270 has the title “GRiD Convertible GT” on the front. The Internet knows them also under the aliases “GRiDPAD 2260”, “GRiDPAD Convertible 2260”, and “GRiD Convertible 2260”. As AST models, they were known under the designation AST PenExec 3/25SL and 4/25SL, respectively.


There were two battery options, a small one and a big one. The batteries were NiCad and there are two peculiarities about it. First, you can load the battery directly from the PSU without a need for the computer as the battery has the power interface. As a consequence, you cannot power the computer without the battery because the computer does not have another power interface.


Second, the battery hangs on two metal heads from the computer. To connect the battery, after putting the battery on the heads, you move the battery to the right where a peg goes into a hole.


The peg is then secured by a flap that needs to be pressed down.


That’s a quite special arrangement. Especially as the big battery that I have cannot hand freely from the computer, but is some millimeters thicker than the computer case. As a consequence, when placing the computer on a flat surface, the battery raises away from the heads and looks awkward. Probably, the smaller battery fits better onto the case.


The system has the typical WACOM pen, and the usual problems finding a space at the device for storing it. Their solution was a somewhat flimsy pen holder in a niche on the right lower part. This solution is not ideal, so in order to fix it, there is an accessory which consists of a string attached to a cap which can be put on top of the pen. The other side of the string is to be attached in a hole that exists for that purpose in the case.


As you might or might not know, I’m rather interested in the PenPoint operating system. This machine falls right into the time period where it could run PenPoint, and there are contemporary GRiD models that were delivered with it, so the question is, was there a PenPoint for the 2260/2270 models? Well, I do not know for sure, but it seems not (according to Dr. Google…). However, there is a mention of a “2260 MIL for PenPoint” file in [http://www.sandyflat.net/digerati/ast486/drivers/grid/index.htm], so maybe PenPoint was initially targeted. We will never know. The hardware, however, could have been easily used, even if the screen in keyboard mode was oriented in landscape, not portrait mode.

Technical Data

Manufacturer: GRiD Systems (AST Research)
Model: 2270
Introduced in: 1992
Initial price: $2995
CPU: Intel 80486SL@25 MHz
RAM: 4 MB (up to 20 MB)
HDD: 80 MB or 120 MB
OS: MS-DOS 6.0, Windows 3.1
Screen: 9.5″, 640×480, black and white, LCD, 64 gray levels
Battery: NiCad, 2.3 Ah, 9.6V, 0.6 Kg (this might be the larger one)
Interfaces: serial, parallel (also used for external FDD), VGA, 1 Type 1 PCMCIA
Weight: 2.1 kg without battery


Once upon a time

April 29, 2018


I recently ordered audio cassettes and a DIN audio cable as new products… I take “Things that belong in the last century” for 100. #thingsourkidsdontknow #longtailproducts

Digital Equipment (DEC) VK100 “GIGI”

April 8, 2018

gigiThe Digital Equipment VK100 or „GIGI“ (General Imaging Generator and Interpreter) seems to be one of DECs approaches of creating an “intelligent” graphics terminal that is capable of processing complex graphic commands. It is not only the device for which the ReGIS system was developed, it even contained a Basic interpreter whose programs could be loaded, saved, and executed via the serial connection from the host computer. It used 8-color bitmap graphics and was based on the Intel 8085 processor. It offered a VT-52 and (some sort of) a VT-100 mode. It connected to an external Barco GD33 RGB monitor.

ReGIS, short for Remote Graphic Instruction Set, was a vector graphics markup language developed by Digital Equipment Corporation (DEC). ReGIS supported rudimentary vector graphics consisting of lines, circular arcs, and similar shapes. Terminals supporting ReGIS generally allowed graphics and text to be mixed on-screen, which made construction of graphs and charts relatively easy.

One thing very nice about the machine is that there is a complete set of extensive manuals available electronically.

The GIGI Basic Handbook tells us the following:

“BASIC is provided as a tool to be used in making GIGI an intelligent terminal. For this reason, only a limited amount of user memory is provided with GIGI. It is therefore recommended that applications and instructional programming be done on the host computer as there is no guarantee of source language transportability between the BASIC in this version of GIGI and that provided in the future”. Now that’s a statement you will read rarely in any manual. Basic programs can have a length up to 7.8 kB.

It also tells us of two Basic modes in GIGI:
“One mode is called local BASIC. In local BASIC mode, the terminal user is in control of the GIGI BASIC system; […] The other mode is host BASIC. in host BASIC mode, the host computer is in control of the GIGI BASIC system; commands and programs come from the host computer, and all input and output default to the host computer.”
In other words: the local Basic mode is the one we know from any other computer, and the host Basic mode gets its instructions from the serial interfaces and write its output to the serial interface.

From a collector’s point of view, the VK100 is somewhat of a conundrum. On the one side it’s only a terminal and has no mass memory interfaces. Therefore, there is also no software for it. On the other hand it’s a full-blown computer with 32 kB of RAM (16kB of which are used for graphics!) and even Basic. It connects to a high-quality monitor and is one of the earliest examples of a terminal that is intended to execute code sent by a server. It is extremely rare and virtually unknown.

Technical Data

Manufacturer: Digital Equipment (DEC)
Model: VK100 (GIGI)
Introduced in: 1982
Initial price: $1500
CPU: Intel 8085A@ 3(?)MHz
RAM: 32 kB (16 kB System RAM, 16 kB Video RAM)
ROM: 28 kB (26kB are used)
Text Modes: 84×24, 42×24
Resolution: 768×240, 8 colors
Interfaces: RS-232C, 20 mA current loop, composite video, printer
Weight: 5.7 kg