Gepard – Part Five b): The Hardware, Phase 2

In this phase, the Gepard becomes a self-contained, autonomous system as all necessary components are available from the Gepard manufacturer. This means text and graphics output, keyboard input, and floppy disk drives. The cards of the First Phase get improved or have successors, and new functionality is added in the form of cards. The second phase is coming to an end when the Gepard Computer GmbH closes.

Second Phase: 1984 – 1986, Gepards as autonomous computers

68010

CPU cards
Now a Motorola 68010 card (also at 10 MHz) is available, replacing the original 68000 card (at least in the Price List 1/86, the old CPU card is no longer available).

512

RAM cards
The first card was a 128 kB DRAM card. It is soon followed by a 512 kB DRAM card, and then by a 1MB one. There is not much to say about these cards apart from you can have up to 7 128 kB cards, or up to 2 512 kB cards, or multiple 1MB cards plus one 512 kB card.

80z

80 Characters card
This is the card used in text Gepards to display text. It can display (surprise, surprise) 80 by 25 characters. Each character consists of a 8 x 11 pixel grid. It can display four different, freely programmable fonts (a 128 charachters each) at the same time. The program to define these fonts is even contained in the Operating System. Additionally, it can display (equally monochromous) graphics with a 320 x 192 pixels resolution. This card can be used in parallel to a GDC graphics card. The standard output interface is a (Y) component cinch plug. The card can serve monitors with a line frequency of 15.75 KHz. The monitor options from the catalogue were a 12″ Taxan KX 1201 or Taxan KX 1203. Recently I had no problems displaying the output on a quite recent Sony 4K TV and an older noname CRT TV.

GDC Graphics card
The GDC graphics card (or, rather, subsystem) is architecturally a marvellous thing, but way too expensive. As it deserves an own blog entry, I will give it one :-).

fpdfpc

 

Floppy Disk system
Such a system consists of a Floppy Controller card and one or two, theoretically even up to four floppy disk drives. The controller card can control either two standard 3.5″ floppy drives or two 5.25″ ones, or up to four “Gepard” 3.5″ floppy disk drives. The data rate can be selected between 250 and 500 kbps. Drives can have up to 2 times 80 tracks. Software-wise a track is divided into 5 sectors of 1024 bytes each. This results in 800 kB disks capacity.
The “Gepard” drives are Sony MP-F52W models that have a data rate of 500 kbps, something the early Gepard newsletters are really excited about. In the first price list (1/85) a full height Sony drive is depicted, a year later the drive is half height. The controller card has two potentiometers with which the Read Pulse Width and the Read Pulse Width can be adjusted.

mfc

Multi-Function card
This cards contains a keyboard interface, a battery-buffered real-time clock, two joystick ports, a programable timer, a PIA, an analogue multiplexer, two D/A converters, and one A/D converter. It was the standard means to connect a keyboard, so these cards are often contained in 2nd Phase Gepards. The keyboard interface is a 5-prong (big) DIN connector. The standard keyboard was a Marquardt type 703 or 704 with a Gepard logo. Later on there was a cheaper option, the “AFC Operator” keyboard. The Multi-Function card was also the audio source and typically the (mono) loudspeaker contained in the computer case connected to the sum of the two D/A outputs. There was no sound chip, so one had to prepare the audio data digitally so it could be put to the D/A converters. There was a program for the Gepard that could play out sample libraries using this mechanism.

img_20181203_214128991.jpg

Parallel/Serial cards
The standard way to connect to a printer was the Parallel-Serial card. It provided two Centronics parallel interfaces and two RS232 serial interfaces. The card even came with a Centronics cable. Additionaly, there was also an 8*RS232c card. It had a massive 50-pin Sub-D jack which provided the 6 signals for the 8 connections.

sram

SRAM/EPROM card
This card has 8 sockets for SRAMs or EPROMS. The advantage of SRAMs is the faster access speed, the disadvantage the higher price. You can mix SRAM and EPROM, but you have to always use pairs of chips. EPROMS provide Read-only memory that is available without having to read it from a floppy disk.

Complete Kits
Also in this phase the kits from the first phase are still available. Additionally, there is now also the C64 version of the Apple II system. Then, there are two new kits. The first kit is the “Text Packet”: a complete Gepard system complete with case, power supply, keyboard, 80 characters card, floppy controller card, one 3.5″ floppy disk drive, a multi-function card, and the elements from the Apple II kit (except the Apple II card). The RAM card is 512 kB, and the I/O card is used as a Boot ROM card. The Text Packet (or variations of it) seems to be the most frequent Second Phase Gepard. And, finally, there is the “Graphics Packet”. It is a Text Packet kit plus a 14″ monochrome monitor and a GDC graphics card as well as a parallel/serial card. The RAM card has now a full MB.

Other cards
There are also a few other cards in the catalogue 1/86:

  • an 8-channel A/D and D/A converter card with 10 bit resolution
  • an 80-channel card with 40 output and 40 input TTL channels
  • a mouse/track ball card with two 9 pin interfaces
  • two MIDI interface cards. One with one MIDI input and one output interface, and one with 8(!) MIDI outputs and 8 MIDI inputs. The latter card even includes six serial ports
  • an IEEE-488 interface card

Tags:

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s


%d bloggers like this: