Mera300

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MERA 302
MERA 302

MERA 300 is an 8 bits architecture minicomputer of polish technology. MERA 300 was also used as a name for continuous series of this type computer. In 1974 was first time showed on Trade Fair and Exhibition in Poznań.

Contents

[edit] History

In 1973 in Poland was designed 8 bits minicomputer - MOMIK 8B (MERA). On a base of this minicomputer in 1974 was made MERA 300 (MERA ZSM). In 1974 on International Trade Fair and Exhibition in Poznań were showed 12 models of MERA 300.

[edit] About family

Family of MERA 300 systems includes:

  • Data processing systems: MERA 300, 301, 302, 303, 304, 305, 306
  • Conversations systems (programs ends): MERA 342, MERA 344
  • Control-steering system (automatic control): MERA 362
  • Universal and single-purpose systems: MERA 392, MERA 396

[edit] System structure

MERA 300 was created from units below:

  • Processors: MOMIK 8b/100, MOMIK 8b/100:250 000 processes/second

[edit] Set of insides facilities

  • For direct work of operator
  • For control and conversion
  • Specializes
  • Outside memory

[edit] MERA 300 computer series architecture

Set of MERA 300 (MERA 302, MERA 303) include:

  • Central unit with “arytmometr” channel
  • Internal memory of 8000 words (1 word=8 bits= nowadays: 1 byte); memory is divided into pages, on each 32 word. Memory of addrssing for instruction include all accessible memory by instruction indicator. Addressing of data consist of two parts: page/word.
  • One class of interruptions system (32 interruptions),
  • Multiplexers channel
  • Outside equipment:
  • printer
  • typewriter
  • reader
  • control desktop

MERA 301 used as a medium magnetic tapes PK-1 and PK-2 with capacity of 0,5 million signs. MERA 305 was extended version with direct memory access (DMA) and system of 128 interruptions divided into 4 classes (4X32). MERA 306 was more complex extended version with:

  • Internal memory divided into volumes each with capacity of 4k words, what gave possibility to extend memory size for about8,15, 24 or 32 k words (nowadays kB).
  • Possibility to use voltage] disappearance system protection
  • Possibility to connect Real-time clock (RTC)
  • Disk memory usage MERA 9425

There where also possibility to connect other equipment like:

  • Monitor and keyboard
  • Specialized keyboard
  • Tape memory
  • Connexion equipment with measurements equipment and industrial automatically machine units. Machine code list of instructions was consisted from 34 positions, which included arithmetical, logical and control instructions.

[edit] Entering and bringing out of data

For entering data in microcomputers of MERA 300 series where used:

  • Tape reader and CTK 50R card reader with control unit JS-CTK 50
  • CT 1001A tape reader with control unit JS-CT 1001
  • CT 2000 tape reader with control unit JS-CT 2000

For letting out data where used:

  • DT 105 tape punch with control unit JS-DT 105
  • DTK 50 tape and card punch with control unit JS-DTK 50

Also where used other inside-outside facilities:

  • TELETYPE MODEL 390 which gave possibility to:
    • Bringing out data from keyboard with printing
    • Bringing out data from tape reader with printing
    • Printing of data with tape punching
  • FACIT 384 typewriter
  • ALFA 311/M monitor, which gave possibility to:
    • Project information on a screen
    • Bringing out information from keyboard with recording data on a tape.

[edit] Usage

[edit] Software

  • OS RTX Real Time eXecutive program

Basic system programs:

It is important that for programmer work on MERA 300 systems Real Time eXecutive program is needed- in MOTIS assembler was self-reliant program, which was able to work without OS.

[edit] List of versions

  • MERA 300
  • MERA 301
  • MERA 302
  • MERA 303
  • MERA 304
  • MERA 305
  • MERA 306
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