Archive for January, 2020

Umtech VideoBrain Family Computer

January 10, 2020

Recently, while searching for another computer, I found a computer in a box in another box that I obviously bought some years ago, but then completely forgot about it. What was even funnier is that I saw this exact model on ebay some days ago and actually thought about bidding for it (which I didn’t). This computer finally sold on ebay for over €850 or $960 even without power supply or joysticks. I do not remember, but I am pretty sure I did not pay that type of money whenever it was that I purchased it.

Okok, to the point: Let me introduce you to the VideoBrain, sometimes also called the VideoBrain Family Computer, the sole model produced by a company called Umtech from 1977 on.

Very unusual for a home computer was the full travel, 36-key keyboard it featured. However, it is said to be poorly designed and difficult to use. Certainly, the choice of functions on it looks very weird.

The VideoBrain had no built-in computer language. However, there was one language available as a cartridge from December 1978. If you would had to guess which language one should offer to home consumers, only a few people would come up with the choice of VideoBrain: APL/S. APL is a programming language which (according to its Wikipedia page) is influenced by “mathematical notation” and influenced itself such crowd pleasers as “MATLAB” and the “Wolfram Language” :-).

Regarding the VideoBrain and APL/S there is a magnificient audio recording from the Third West Coast Computer Faire conference in 1978. This recording was made during the presentations of the Conference. Thir first and second presentation are:

  • Ted Haynes: Videobrain and the APL/S Language
  • Robert G. Brown: An Introduction to APL/S: A Modern Computation Language for Personal Computing

and you can listen to them in very good quality using the last link in the references.

And, you heard it here first, the $150 APL/S cartridge actually had not only ROM, but also more RAM (if you listen to the presentations from the last paragraph). This is also hardly surprising as 1 kB of RAM is hardly enough for a (later) Sinclair ZX81 with its efficient, token-based program representation, let alone APL, a language that can handle entire number arrays with a single operator. <update>[Brown78] states that the cartridge had 13 kB of ROM and 1(!) more kB of RAM.</update>

When you listen to the presentation of Robert G. Brown, you can also hear his rationale of offering APL as opposed to Basic, namely the higher productivity and better degree of programming structures. These are, of course, honorable reasons for a computer scientist, but seem a little bit odd for an entry-level computer with hardly enough memory to actually have program readability problems :-).

The above presentations are also contained as text articles in the Proceedings of the Third West Coast Computer Faire conference. But if you are interested in the APL dialect, also Byte had an article by Robert G. Brown, the author of APL/S in the December of 1979 issue, and this issue is online (see references below).

The main differences of APL/S to APL are:

  • APL/S is a subset of APL
  • all these pesky special characters the original APL needs as operators (like the arrow and the star-im-a-circle) are replaced by ASCII strings
  • arrays in APL/S are restricted to one dimension and subscript expressions must evaluate to scalars
  • APL/S adds control structures like IF and WHILE

APL/S uses a two-part user interface. In the lower half the user can enter and execute code. The upper half is reserved for bar charts. For variable names, only the first four characters are used.

The VideoBrain was the first home computer system where the software was available as cartridges. These could contain of up to 12 kB of ROM. Fewer than 25 software titles were ever markteted for the VideoBrain.

The used CPU is quite old and exotic. It is a Fairchild F8, which consists of two chips (the CPU and the “Program Storage Unit”. This sounds awkward, but was actually a technical achievement in 1975, at a time when earlier CPU designs distributed the needed functionality over a larger number of chips (sometimes 7 or more chips). Later on, CPUs assembled all functions in one chip. As a result, the F8 was quite economic, which, according to [CPU Museum], made it in 1977 to “the world´s leading microprocessor in terms of CPU sales”. However, as we know, the number of computers exploded only after 1977, and these computers used other CPUs. Therefore, it is not surprising, that there aren’t that many F8-based computers. There is the VideoBrain, and there is Fairchild’s own console, the Channel F Video Entertainment System from 1976.

Due to the high cost of RAM at that time, the machine came only with 1 kB. However, it had 4 kB of ROM, providing four built-in programs: a simple text editor, a clock, a count down timer, and a color bar generator.

The basic computer itself does ntot have any possibility to save data, you had to buy the “Expander 1” if you wanted to have cassette tape recorder interfaces (and two RS232 interfaces). The “Expander 2” was a 300 baud modem.

Graphics on this machine seems to be complicated. [SeanRiddle] says “This document describes the VideoBrain grapics hardware. It is a sprite engine, capable of displaying 16 sprites simultaneously. The control registers are documented pretty thoroughly. The sprites are monochromatic, but each can be a different color. There is one bit each for RGB, and 2 bits of intensity info (but maybe only 2 intensity levels are usable). The registers allow for a sprite up to 248×256 pixels, positioned on a grid 256×512 pixels in size. Sprites can be displayed at twice their horizontal or vertical size. There are 2 “display lists” for setting the y position and drawing priority of the sprites. There is also a mode called “xcopy” that replicates the first byte of a sprite horizontally.”

The computer was not widely available, but was sold for a short time by Macy’s department store. As you can imagine, the VideoBrain was not a large success, and it vanished from the market after 3 years.

The Wikipedia article on the VideoBrain talks about the fact that the VideoBrain had no real defined target audience and therefore could not satisfy anyones needs (in contrast to the Apple II), and that’s certainly true. From my point of view, the VideoBrain tried to be both a games console (small memory, cartridge slot, 4 joystick interfaces, no cassette interface) and a computer (full keyboard, programming language available from 1978, computer interfaces available in expansion module), but did both things badly.

Technical Data

  • Manufacturer: Umtech
  • Model: VideoBrain Family Computer
  • CPU: Fairchild Semiconductor F8 @ 1.79 MHz
  • RAM: 1 kB
  • ROM: 4 kB
  • Graphics: 16 colors, sprite engine (see above)
  • Interfaces: 4(!) joystick ports, TV RF connector, cartridge, expansion port
  • Released: 1977
  • Initial price: $500 (basic device)


Gepard – Part Seven: The Gepard Company

January 6, 2020

As with many startup companies, the history of the Gepard company is very intense, but unlike many unsuccessful startups, it is both rather short *and* produced tangible results in time.

So, let’s start at the beginning.

It is the year 1983. The computers in the consumer market are mainly 8-bit computers. It is already clear at this point that the Next Big Thing will be 16-bit computers, but in Germany you can buy 16-bit computers only as expensive, professional computers. Examples for these models are:

  • the HP 9816 (starting at $3895 or about DM 14,000)
  • the Tandy TRS 80 Model 16 (admittedly more a semi-professional machine) at about DM 17,500
  • the Fortune 32:16 at DM 25,000

In the US, there is the “Dtack Grounded” single board computer sporting a Motorola 68000 CPU at the maximally possible 12 MHz. It uses SRAM in order to use this speed, but the board does not offer too much more. The people behind this computer also publish a newsletter of the same name which is informing its potential customership about the current developments regarding this board and the industry.

Having this in mind, a group of friends aims at founding a computer company that targets a computer these group would like to buy themselves. The assumption behind this strategy is that such a computer should meet the needs of a market of similar minded people. The requirements of this computers would be:

  • a Motorola 68000 CPU
  • modular design for maximal flexibility
  • initially designed as an add-on for an Apple II computer because:
    • the friends are Apple fans
    • this approach has the advantage of not needing to develop own UI and storage hardware from the start
    • this allows for a cheaper price for the first product

This company, the “Gepard Computer GmbH & Co. KG” is founded in Oldenburg, Germany in August 1984. The initial founders are:

  • Thomas Schumann
  • Herman Spille
  • Klaus Onnen

Later on, two more founders join:

  • Meinolf Schneider (nowadays: Amekudzi)
  • Bernd Heyer

In order to finance the company, each founder has to contribute DM 40,000. More money is contributed by an investor. The inital round of financing sums up to DM 410,000. A second round adds additional DM 180,000.

In the spirit of Dtack Grounded, also Gepard published a periodical newsletter on paper even before the actual company was started. It informed potential customers and interested parties about the current and upcoming state of Gepard developments, it provided information in different, related topics, and it dissed the competion. The newsletter was completely free. It was published from October 1983 to March 1986 in 12 issues of typically 12 A5 pages in an edition of 500 copies each. The newsletter lead to several contacts, not least it was read by a contact of the later investor of Gepard.

Development of the hardware starts already in 1983. The founders and some first employees design three cards (CPU, RAM, Apple II Interface) for the Gepard, a backplane, an Apple II card (which connects to the Interface card), the Modula-2 compiler, the operating system (GDOS), and the software that runs on the Apple II. They have the PCBs then produced locally (in Oldenburg), buy components, and populate and solder the PCBs themselves. A first run of 30 sets is produced and in 1984 the first sets can be sold to the people who had registered via the newsletter.


Marketing-wise, Gepard was not very active, but tried to get the most out of its limited effort. The main marketing channel was the Apple User Group Europe (AUGE). So it distributed the newsletter generously via AUGE channels. In the newsletter readers could register an option on a Gepard for free. 30 options were registered and 3/4 of the options were resulting in purchases. AUGE was divided in regional chapters, and in many of those chapters there was one Gepard owner, so there was always one to present a Gepard or who could be asked for opinions. As a consequence, and because of a 10% commission Gepards are mainly sold by word of mouth and by existing customers. There was also an article in the AUGE magazine (8/84) on the Gepard. Articles on the Gepard are very rare, not least because at that time, journals prefer promoting their own computer projects than reporting on a new computer with a very small customerbase. Nevertheless, Gepard also runs (small) ads in the most important computer journals. Finally, Gepard is represented with (probably very small) booths both at the Hannover Messe 1986 and at the Orgatechnik 1986.

In 1984, Apple releases the first Macintosh, also a 68000-based computer. Fortunately for Gepard, although the Mac has a mouse and a GUI, and is sold complete in a neat, compact package, it is more expensive (at DM 10,000), and it is (at 8 MHz) slower than the Gepard. It is also by and large not expandable. As also the typical customer of a Mac and a Gepard differ substantially, the Mac is no threat to the Gepard.

Until 1985 Gepard had 70% private and 30% professional customers. In the fall of 1985 Atari starts selling a new model, the Atari ST for an unrivaled low price (~DM 3,000 including floppy disk drive, monitor, mouse, and GUI) and basically ends sales of Gepards to private customers. The Gepard company does not know how to react to this competition, has not finalized all of its developments and is out of money. Eventually, 1986, the company files for bancruptcy.

In hindsight, Thomas Schumann, the former CEO of Gepard, thinks that it would probably have been possible to save the company if the management would have had more experience, and if it would have moved its focus to professional customers, offering a Unix-like operating system. After having found that the later 68020 version of the Gepard was quite unique at least on the German market for its price, I agree.

After Gepard went bust, one of the original founders, Hermann Spille founds his own company, HS Computer, to continue the Gepard business. He continues selling hard- and software from the Gepard catalogue, but also develops and sells new hardware. The most important development activity is the finalisation of the 68020 card and the development of the second version of this card. Other hardware includes:

  • a Z80 card
  • an EPROM burner

Apart from HS Computer, there are a whole number of small projects starting in the aftermath of Gepard:

  • ports of OS-9, PC DOS 2.1/GemDos, Eumel/Elan are started or at least proposed
  • version 1.4 of GDOS is finalized by Thomas Tempelmann
  • version 2.0 of GDOS is written by Harald Hellmann
  • an “Atari ST” graphics card is developed that can be connected to an Atari monitor

But eventually, over time, the Gepard business trickles off and HS Computer is liquidated in 2009.

Ok, so, here you have it. My collected findings about the German Gepard computer. I hope you liked it. It took me a long time to collect, analyse, and write, but it was fun, it was new, and it was basically never documented before (especially in English).

Gepard – Part Six: The Software

January 1, 2020

Let’s talk about the software in the order in which it was developed. We therefore start at the beginning (in Gepard terms): the Modula-2 compiler.


One cannot talk about the Gepard story without mentioning its Modula-2. Following the Zeitgeist (and Apple) not only should the operating system of the Gepard be written in Modula-2, but this computer language was also foreseen as the system language, the main application language, and the shell/batch language. This meant e.g. that all hardware was accessible to Modula-2 languages, by providing corresponding libraries.

The Modula-2 compiler was initially written by Jürgen Müller (who did not have much experience in this matter) directly in Assembler. The development started as a cross-assembler project on an Apple II. As soon as enough developer systems were produced, the development was moved to a Gepard itself, and as soon as no Apple II (or C64) was needed anymore, everything was done on the Gepard itself. As a result of being developed in Assembler, the compiler was very fast at compiling code (one Gepard manager believe it to be the fastest M2 compiler at that time in the world). As a result of the main programmer being not that experienced in that area the compiled code was not that fast (although the comparison of the Gepard Modula-2 to any Apple II compiler went of course very well for the Gepard as proven by the original comparison from 1985(?) below).


source: 68000=news Nr. 6

Users of the Gepard Modula-2 also often mentioned the completeness of the compiler positively. Being the main system language, it even featured an inline assembler.

Jürgen Müller received a royalty of 22.50 DM per Gepard for the compiler.

Later on, the Gepard M2 was ported to the Atari ST under the name “Megamax Modula-2” by Thomas Tempelmann. It was then distributed by “Application Systems Heidelberg”, which was funded later on by another former employee of Gepard. The initial version was mainly a pure port of the original Gepard version, later issues had improved features. The lower execution speed of the compiled code was also mentioned in comparative reviews of different Atari ST Modula-2 compilers.

However, the Modula-2 compiler was certainly the main reason to buy a Gepard before OS/9, because there was simply no other language you could use (except Assembler) nor any standard binary format of a program that could be executed.

The (original) Operating System: GDOS

The focus on a programming supporting software system continues on the User Interface side: it is a clone of the UCSD Pascal UI. It is all text, no mouse pointer nor windows in sight. All you have are a fixed set of commands that you reach by typing a single key. Some of the commands are displayed in the first line of the screen. If you branch into one command (which is an application on the top level), you have another set of sub command, some of which are displayed on the top.

Some of thes applications on the UI level are: Editor, Compiler, Monitor, Filer (a program that can do things with files).


This is a strange version “1.4cv”

One could argue that it would have been better to use a standard Operating System, but apart from Unix (which basically required a harddisk) there was not really one. The was CP/M-68k, but this was hardly standard and would have offered only a few advantages while being costly.

However, the lack of Unix was probably *the* problem that prevented the success of Gepards in the professional area after the Atari St and the Amiga had killed the private market for the Gepard. If it would have offered Unix, a Gepard would have been probably a cheaper alternative to “professional” 68000 computers, especially after having finished the development of the 68020 cards.

During the time of the Gepard company, GDOS was developed up to version 1.3*. Version 1.4 was finished after the Gepard company went bust. It was developed by Thomas Tempelmann, who tried to convince Gepard users to pay him some money for the version because the development was no longer financed by Gepard. It is not completely clear to me whether 1.4 was the last “official” version of GDOS because I have a version 1.5 from the floppy disk remainders owned by Jürgen Müller, who was obviously part of the special interest group GDOS maintenance who is mentioned on the splash screen of version 1.5.

A much more capable version of GDOS was always in the planning, even at the time of the Gepard company. A corresponding, much improved version of GDOS was later on published as “GDOS 2.0″ (and later on called OS/Science”) offering e.g. multitasking, different fonts, etc. However, as far as I can tell, this was never delivered with later Gepards, but needed to be bought as a separate software for DM 400.

Application Software

There wasn’t much application software as far as I can tell.

There was Gepard’s own editor (GepStar, a WordStar-like program) and Gepard’s own spread sheet program, GepCalc. Initially sold separately, it was later on bundled with GDOS 2.0.

There was Gepard’s own PCB layout program, PlaTool, which Gepard used itself to design new cards.

Then, there was a small catalogue of little tools like GepTerm, a terminal program, a disk with utilities, one with test tools, disks with Modula-2 libraries for mice and graphic tablets, the GDC graphics, and the graphics of the 80-characters-card. There was a small sampler program, and two disks with samples.

For GDOS, GepStar, GepCalc, and the Boot ROM images, you could also get the source code.

The other Operating System: OS-9

OS-9 is a Unix-like multi-user, multi-tasking operating system originally developed for the Motorola 6809 processor by a company called Microware Systems Corporation. It was originally developed from 1979 as the operating system for the BASIC09 project fundedy by Motorola. At that time it was used mainly for TRS-80 Color Computers, and Dragon computers (requiring a floppy disk drive). In 1983, OS-9 was ported to the Motorola 68000 CPU.

In contrast to most operating systems, OS-9 was sold mainly as a 3rd-party-product that needed to be purchased by the users. Therefore, also the Gepard version of OS-9 was sold for about DM 750 from about the end of 1986 onwards. At Gepard times it had a small but active community including an own newsletter. On the Gepard, OS-9 uses its own file system and cannot be copied by GDOS tools.

You can still get OS-9 for many computers today.

Even if you cannot copy OS-9 using GDOS, you can copy it using OS-9. First, boot OS-9. As the user name, use an empty string, i.e. just hit ENTER. Now, you can format a new floppy disk with format /d0 (if you want to use the first drive) or format /d1 (for the second drive). Using the backup command, you can copy disks. For a cheat sheet of OS-9 commands, look onto the last page of this file.

Software, that did not really make it

CP/M 68k

This actually appears in the 1986 price list including a C compiler for DM 1225. I know someone who claims that he actually tried it. However, I do not know anybody who claims to have actually used it. Technically, it would not have been impossible to actually port it. Most probably, the price was basically determined by the license fee and it offered not that much of a benefit compared to GDOS.

PC DOS 2.1/GemDos

In 1986, in the aftermath of Gepard Computer GmbH going bust, someone asked for subscriptions to a project that wanted to port GemDos to the Gepard. It would include PC DOS 2.1 and the GEM Desktop and would cost DM 499.- If 100 users would subscribe, they would buy the license from Digital Research and start porting the software. I never read anything about this project again, so probably the 100 subscriptions never happened. Also, it seems a little bit like a stretch to port PC DOS to the 68000.


Elan (Education Language) is a programming language that was developed in 1976 in Germany. The Operating System to run it was called Eumel. Like the GemDos porting project, this was an attempt by an individual to open the Gepard to other software worlds. Like GDOS was written in Modula-2, Eumel was mostly written in Elan. The price for a multi-user version would have been DM 750.-, but like the GemDos port, this project seems to have never materialised.