EC 1040

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The electronic data processing system EC 1040 (working and common name R 40 ) was a mainframe computer of the Robotron combine as part of the ESER . It was developed according to the operating principles of the ESER series I and thus compatible with the IBM System / 360 . The core was the central unit EC 2640 , which was completed with control units and devices from the ESER for the data processing system.

Development, manufacturing and sales

The development of the central unit EC 2640 and some peripheral devices (e.g. interrogation unit, perforated tape station, screen station) began, building on the experience of the development of the Robotron 300 and the Robotron 21 , in the VEB Electronic Calculators (ELREMA) Karl-Marx-Stadt . At the end of development, this development company was already integrated into the Robotron combine as a device department.

The production took place in Robotron Elektronik Dresden (RED).

The distribution took place after completion with further imported peripheral devices of the ESER as electronic data processing system EC 1040 from Robotron Distribution Berlin (RVB).

The central unit EC 2640

Central unit EC 2640 in the test field of VEB Robotron Elektronik Dresden

Technical-constructive basis

The central unit EC 2640 was developed on the basis of the first TTL circuit series available in the GDR (exclusively with slow and fast NANDs , AND-OR inverters and the JK flip-flop). A maximum of 60 circuits, 14 electrolytic capacitors and 12 diode blocks are accommodated on a multi-level circuit board with up to 10 layers with an indirect 90-pin connector . A maximum of 40 such plug-in units are plugged into a so-called “panel” and wired with one another and with connectors for 38-pin ribbon cables using “winding technology”. The latter have direct connectors and represent the connection between the panels. Up to 6 panels (some for power supply) are housed in a frame. Each three such frames (the two outer ones each pivotable) ultimately occupy a cabinet. The entire central unit consists of two main storage cabinets, one cabinet for the power supply of the main memory, two cabinets for the central processing unit and the channel controls, one cabinet for their power supply as well as an operating and display panel. All six cabinets are arranged in the shape of a cross.

Operating principles

Since the operating principles ( i.e. the programming interface ) of the ESER series I correspond to those of the IBM / System360, nothing further is explained here.

Logical structure and functional data

The main memory (HS) is a ferrite core memory and was offered in the capacity variants 256 KByte, 512 KByte and 1 MByte. A memory cell has a call width of 64 bits plus 8 check bits . The cycle time is 1350 ns. For the purpose of entanglement, it is divided into four autonomous blocks, which can be addressed one after the other in the speed of the cycle. The main memory switch (HSV) has the task of coordinating the memory requirements of the channels, the processing unit, the command preparation unit and the timer in a prioritized manner and ensuring memory protection.

The central processing unit (ZVE - what is commonly called a CPU today ) has a processing width of 64 bits and consists of the command preparation unit, the microprogram control unit and the processing unit. The sequence-controlled command preparation unit (BVE) reads the commands linearly in advance and carries out any necessary address calculations in the address arithmetic unit. The microprogram control unit (MPSW) controls command and interrupt processing in the processing unit. It has a 3K × 130-bit microprogram memory with 100 ns access time on the basis of a “threaded” ferrite core read-only memory . The processing unit consists of the dual calculator, the decimal calculator, the exponent calculator and the register memory. The operating speed of the CPU is specified as 320,000 operations / s.

The sequence-controlled channel control units (called channels for short) are able to carry out a complete input or output process under program control after being initiated by the CPU. While a selector channel can only process one such channel program at a time and transfers up to 1300 bytes / s, a multiplex channel can process several programs in parallel, but is only suitable for low data transmission rates. Several peripheral devices or device control units are connected to one channel each with a standardized peripheral bus. The associated standard interface (SIF) was electrically and functionally compatible with the IBM System / 360, but in terms of construction it had different ESER-specific connectors. Original IBM devices could therefore also be coupled using special adapters.

Test and diagnostic strategy

Due to the static behavior of all memories, it was possible to realize a cycle stop of the whole machine without data loss. For this purpose, a micro-command address could be set as a stop address on the maintenance field and work could continue in step-by-step mode. The static troubleshooting was done with simple logic test pins. The troubleshooting was supported by the self-test of the ZVE with special test micro programs. These were supplemented by an extensive (operating system-independent) set of test programs at machine command level. Main, register and microprogram memories were protected by parity bits .

Power and clock supply

Two cabinets (4 kW for main memory and 17 to 19 kW for central processing unit and channels) are required for power supply alone. The peripheral devices can also be switched centrally via a so-called “power supply interface”. A central emergency switch is used to quickly switch off all system parts. Several fans are installed in the upper part of each frame to dissipate the heat. To increase safety after several fires, they were equipped with ball bearings and protection against overheating.

The flip-flops of the central unit EC 2640 are synchronized by a two- clock system with 450 ns clock cycle time. The two phases of the “mother cycle” are generated in a central clock generator, distributed via coaxial cables to adjustable “clock sub-centers” and finally to “clock drivers” on the individual plug-in units.

Peripheral devices and control units

  • The AE EC 7073 query unit is essentially an "electronic typewriter" for communicating between the operator and the operating system.
  • The perforated tape station LBS EC 7902 consists of one or two tape readers and a tape punch and is mainly used to enable communication with older systems based on tape .
  • The punch card reader LKL 6012 reads 80-column punch cards , which are the main input medium for this generation of computers.
  • The punch card punch LKS 7012 punches 80-column punch cards .
  • Up to 8 removable hard disk drives WPS EC 5055 serve as external direct access memory with 7.25 Mbytes per disk stack and are controlled by the large-capacity storage controller GSS EC 5555.
  • Several MBG EC 5016 magnetic tape storage devices serve as sequential mass storage devices and are controlled by the EC 5516 magnetic tape storage control device .
  • The parallel printers PD EC 7035 and EC 7031 work with a rotating type roller and print up to 1200 or 1800 lines per minute.
  • The BSS screen system consists of a screen group control unit, up to 16 screen control units and two screen workstations per screen control unit with 16 lines of 64 characters each, a keyboard and a light pen.
  • The optical document reader OBL reads printed and handwritten stylized characters on paper.

Operating systems

  • The DOS / EC operating system is a simple operating system and corresponds to the IBM DOS / 360.
  • The OS / EC operating system is a powerful operating system and corresponds to the IBM OS / 360 .

literature

Individual evidence

  1. ↑ Lutz Kern, Klaus Ober, Jörg Schumann: ESER - programming in the DOS / ES operating system (=  series automation technology . No. 142 ). Verlag Technik, Berlin 1973.
  2. ↑ F. Reason: Principles of the OS / EC operating system . German Science Publishers, Berlin 1981.

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