HT-1080Z school computer

Computer science education (mainly in primary schools)

Various educational institutions, including 1,861 primary and secondary schools

Structure

Central unit

• control unit:Zilog Z80microprocessor
  • 16-bit address bus, 8-bit data bus, control bus
  • clock speed 1.77 MHz
• main store:
  • first set 16 KB, second set 64 KB RAM
  • 12 KB ROM for compiler + 1.5 KB ROM expansion (for Hungarian accented characters)
• calculator: ALU built into the microprocessor

Periphery

• backup storage: built-in cassette recorder (500 baud)
• peripheral devices:
  • input: full keyboard (characters+control keys+numpad)
  • output: composite video signal for monochrome monitor; later analog antenna signal for TV
  • AY-3-8910 sound generator (3 channels and noise, 11 octaves)
  • interfaces:
    • tape recorder connector for external tape recorder
    • 8-bit input/output ports (on the tone generator)
    • 50-point expansion rail connector
    • external expansion box for floppy disk control
    • color graphic supplement (MICOLOR-01)

The power supply was provided by a built-in power supply.

Operation

The microprocessor is an extended instruction set version of the Intel 8080; a more detailed description of its structure and operation can be found at the link above.

The 16-bit address space allowed direct addressing of 64 KB of storage, also supporting DRAM refresh (one/two 'refresh cycles' were built into each instruction execution cycle).

The calculator could perform additive arithmetic, as well as logical and shift operations.

Screen resolution:

• in text mode 16 lines, 32 chpl (half screen) or 64 chpl
• in graphics mode 128*48 pixels, monochrome

Program set

• there was no operating system
• compilers: BASIC (Microsoft, 12 KB Level II version)

There were only unique developments that were not put on the market.

Historical curiosities

The computer was made excellently suitable for school use by its durable, high-quality keyboard and compact design: it contained the central unit, keyboard, power supply and cassette recorder all in one.

A TV or monitor served as a display; however, it was not cheap in its time; for this reason, individuals did not buy it very often.

However, machines manufactured after 1986 were no longer very popular, mainly for the following reasons:

• The basic model (TRS-80) was made with the technical standards of the late 1970s, so the HT 1080Z was not up-to-date even when it was released.
• Among the Hungarian computer types, the Homelab/Aircomp and Primo types released from 1984, as well as the Videoton TV Computer released in the mid-1980s, were considered to be the most "human-friendly".
• Among the foreign models, the Sinclair ZX-81 was significantly cheaper (for which there was even a 64K RAM expansion); the ZX Spectrum and Commodore-64 models, which were very successful in the mid-1980s, offered finer-resolution color graphics and a wider range of programs.
• In the framework of the second school computer program (after 1986), Commodore models were already supported; the winning Hungarian developments (such as ProPrimo or HT-3080C) remained at the prototype level.

Resources

Short review: The Past of the Future, pages 166-168

Variants and specifications: HT computers

Further analysis: World-famous series in Hungary, part 5