The P8000 is a microcomputer system and was developed in 1987 in the German Democratic Republic (GDR) by VEB Elektro-Apparate-Werke Berlin-Treptow "Friedrich Ebert" . It consisted of an 8-bit and a 16-bit microcomputer part with an associated Winchester disk controller and was intended as a universally applicable programming and development system for multi-user / multi-task applications.
In addition to the variant with a 16-bit microcomputer, there was also a downgraded variant with only an 8-bit microcomputer.
The 8-bit microcomputer
The 8-bit microcomputer of the P8000 was physically located with all of its functional modules on a single 4-layer circuit board in the format 380 mm × 250 mm. The computer with a clock frequency of 4 MHz was based on the U880 microprocessor and its peripheral circuits plus the U8272 floppy disk controller . Direct memory access was guaranteed with the help of the U858-DMA peripheral circuit .
In addition to the 64 KB dynamically working RAM, 8 KB EPROM and 2 KB static RAM were available as main memory for system startup, system test routines and the system monitor. These additional memories could be moved or switched off in 4 KB increments in the 64 KB address space.
The 8-bit computer had four serial channels which were designated tty0 to tty3. The interfaces worked with both V.24 and IFSS signals. In addition, the computer had a parallel interface which allowed an EPROM burner to be connected. Another internal 32-bit parallel interface was used to couple the 8-bit with the 16-bit microcomputer card. The data exchange took place via two 5.25 ″ floppy disk drives built into the device. Two additional 5.25 "or 8" floppy drives could be connected externally.
The 16-bit microcomputer
The 16-bit microcomputer of the P8000 is divided into the two functional modules 16-bit computer card and up to four plug-in main memory cards with sizes of 256 KB or 1 MB each. The 16-bit computer was housed on a 6-layer circuit board measuring 380 mm × 250 mm. The computer worked with a clock frequency of 4 MHz and was based on the 16-bit U8001 microprocessor . In connection with a special control logic, three U8010 memory management modules took over the dynamic memory segment allocation in the main memory and protection against unauthorized access. The computer also had 16 KB EPROM memory and 2 KB static RAM for the system monitor and self-test routines. The periphery was formed by circuits from the U880 family . A corresponding control logic ensured the interaction with the U8001 main processor.
The 16-bit computer had four serial channels which were labeled tty4 to tty7. The interfaces also worked with both V.24 and IFSS signals. The 16-bit computer was connected to the 8-bit computer via an internal 32-bit parallel interface. The connection to the external Winchester disk add-on was implemented via another parallel interface.
The Winchester disk controller
The Winchester disk controller (WDC) is an intelligent hard disk controller and was located in a separate device, the Winchester disk add-on . In addition to the actual Winchester disk controller, this device also accommodated up to two hard drives.
The WDC was implemented on the basis of the U880 microprocessor . 8 KB EPROM were available as program memory for the firmware. 6 KB of static RAM were used to temporarily store the data on the way from the host computer to the hard disk. The communication between the WDC and the host computer took place via an eight-bit parallel interface in conjunction with additional control bits. The interface implemented the block-wise transmission of the data as well as the command and acknowledgment information.
Up to two (identical) drives with an ST506 interface were used as hard disk drives . While the disk parameters were still permanently included in the firmware in the first firmware versions, from firmware version 4.2 it was possible to use any MFM hard disk. In addition to the information about defective sectors, from version 4.2 the disk parameters were also saved in the 1st sector of the hard disk.
The P8000 terminal served as the input and output device for the P8000. It consisted of a green monitor, a keyboard and a control computer. The terminal supports the ADM31 and VT100 operating modes . The terminal offered the possibility to switch between two character sets which were stored in separate EPROMs. The interface offered the operating modes V.24 or IFSS . The control computer is based on a U884 and the graphics controller KR580WG75 (Intel 8275). Acoustic signals were issued with a piezophone.
The P8000 Compact, developed in 1989, was a further developed version of the P8000. In the P8000 Compact, the Winchester disk controller was located together with the hard disk in the housing of the main computer. This eliminated the need for an extra side plate. In contrast to the P8000, the P8000 Compact was delivered as a 16-bit version with a battery-backed real - time clock as standard . Upon request, the P8000 Compact can also be supplied with a third CPU, the U80601 . The P8000 Compact was the last computer developed by the EAW.
- P8000 Compact
- UDOS - compatible Z80-RIO
- OS / M - compatible CP / M
- IS / M - compatible ISIS-II
- WEGA - compatible UNIX
- IRTS 8000 - a real-time operating system
- DCP (only with 3rd CPU under WEGA ) - compatible MS-DOS
The price for a P8000 system when it was launched was 17.2125 marks . Friends of historical computing technology today pay collector prices for devices and complete systems. While the 8-bit version was just 101 euros in 2012, a complete P8000 development environment achieved 767 euros in the same year and a P8000 Compact in 2016 1066 euros.
- L. Claßen: Introduction to the software of the device system P8000 VEB Elektro-Apparate-Werke Berlin-Treptow "Friedrich Ebert"
- W. Zuchhold: P8000 hardware manual VEB Elektro-Apparate-Werke Berlin-Treptow "Friedrich Ebert"
- Description of the P8000 ( memento from April 29, 2013 in the Internet Archive ) on Oldbits.de
- P8000 on Robotrontechnik.de
- P8000 Compact on Robotrontechnik.de
- Pofo.de - very detailed private page on the P8000 and WEGA
- The P8000 in pictures and in function on video at robotron-computermuseum.efb-1.de
- P8000. In: Robotrontechnik.de. Retrieved October 28, 2015 .
- Online auction of a P8000 (8 bit) on eBay , May 27, 2012
- Online auction of a P8000 programming and development system on eBay, May 10, 2012
- Online auction of a P8000 Compact on eBay, March 20, 2016