MERA-400 POLISH COMPUTER
TO USE IT BUILD A CONTAINER LOADING STATION AND CHOSE THE TYPE TO BE MERA-400
Best of the best…
The MERA-400 is a 16-bit minicomputer designed in Poland. It was produced between 1976 and 1985 at the Zakład Komputerów Fabryki Mierników i Komputerów ERA w Warszawie at Łopuszańska Street 117/123. In the years 1985-1988 further development of the computer and servicing of the existing existing installations was handled by the Foreign Enterprise Amepol.
A total of just over 650 copies were produced (656 is the highest known serial number of the central unit produced in 1986). The MERA-400 is the successor to the K-202. Its design took into account the ease of portability of the software that had been developed for the K-202, while removing the flaws in the architecture of its predecessor. The system can be equipped with up to two processors operating concurrently using a common bus and shared memory areas memory. The processor operates on 16-bit data and uses 16-bit addresses within a single memory segment, allowing each processor to address 64k 16-bit words. The number of memory segments used is limited by a 4-bit register block number (NB), giving a total address space of 1M words (however, the the amount of physical memory used by the computer may have been greater). The speed of the MERA-400 processor is not described by the frequency of the clock because it does not have one. Its architecture is asynchronously sequential, and the only measure of performance is the number of commands executed per unit of time. This averages around 400,000s of operations/second and depends not only on which instructions are currently being being executed at any given time, but also depends on the parameters of the integrated circuits used to manufacture of a particular unit.
The processor allows the handling of 32 interrupts grouped into 11 levels, and its command list includes 121 items. It can also be equipped with an additional Multiple Precision Arithmometer allowing operations on 32-bit long numbers and 48-bit floating-point numbers.
The system interface is asynchronous, which makes it easy to connect devices with different dynamic parameters to the system. This applies to both operating memory and external devices. The system 16 input-output controllers (channels) can be connected to the system, each of which can each capable of handling a wide range of devices: from character terminals, printers, readers and tape perforators, through flexible drive stations, hard drives and tape hard drives and tape memories, to automation and other specialised devices.
Fun facts:
If we compared MERA-400 to INTEL 8086 cpu the system will outpreform any viable 8086 configuration.
At the Academic Navigators Guidance Training Centre at the Air Force Academy in Dęblin houses one of the last examples of the MERA-400 minicomputer. It is unique because it is still working and fulfilling its purpose. The computer is located in the Navigational Training Devices Laboratory. It runs the IKS-80 Aircraft Guidance Imitator OBERON, developed on behalf of the Air Force Institute of Technology. The machine, together with specialised external equipment and software, is used for guidance training.
The MERA-400 could have operated in a dual-processor configuration, but it is likely that no such machine has worked in production anywhere. The only known experimental dual-processor configuration worked at the University of Warsaw.
With a little reworking of the processor, for byte operations fetch/write operations the address could be calculated on 17 bits (PRE-modification and B-modification). As a result, 128kB could be addressed in a block. This modification was present by default in the MX-16 processor, and its absence in the MERA-400 processor was most likely an error.
MULTIX and PLIX, as units built for the MX-16, were installed in MERA-400s in operation at Amepol’s customers. About 100 such installations were made.
15 prototype units of the MERA-400 were produced, built on the based on ferrite memory produced in Japan, with physical dimensions physically several times smaller than that produced at Elwro, but of the same capacity capacity. This also allowed the minicomputer to have a much smaller in size.
The most popular operating system was CROOK developed at the Institute of Marine Gdansk University of Technology. The system family includes versions 1 to 5. The first three were written for the K-202. The first three versions were written for the K-202, the third version was the first to operate also on the MERA-400. Subsequent versions were created only for the MERA-400.
For more information please study the official brochure on mera400 wiki (Steam dosent like the links we provided)
