yann64andClaude Opus 5.5
b274874139
1,289 discussions, 9,527 archived comments; pages no longer carry the comments themselves. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01YDRjtmAiNpo5mK5N3d7QwZ
173 lines
7.4 KiB
Markdown
173 lines
7.4 KiB
Markdown
---
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title: MERA-ELZAB Meritum
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categories:
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- Computers
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types:
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- Home Computer
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origins:
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- Poland
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years:
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- '1983'
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cpus:
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- U880D CPU
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params:
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name: Meritum
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image: /media/museum/photos/mera_meritum_system_s1.jpg
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company: /companies/mera-elzab
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company_name: MERA-ELZAB
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specs:
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- label: NAME
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value: Meritum
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- label: MANUFACTURER
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value: Mera-Elzab
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- label: TYPE
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value: Home Computer
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- label: ORIGIN
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value: Poland
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- label: YEAR
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value: |-
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Model 1 : 1983\
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Model 2 : 1985
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- label: BUILT IN LANGUAGE
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value: Basic
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- label: KEYBOARD
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value: |-
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QWERTY full-stroke keyboard, 57 keys, arrow keys\
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NMI, CTRL, SHIFT (x 2), ENTER, CLEAR, BREAK. Two keys are blank
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- label: CPU
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value: U880D CPU (east-german Z80 clone)
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- label: SPEED
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value: 2,5 Mhz
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- label: RAM
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value: |-
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Model 1 : 16 KB\
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Model 2 : 48 KB (up to 64 KB)
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- label: VRAM
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value: 1 KB
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- label: ROM
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value: 14 KB
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- label: TEXT MODES
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value: 32 chars x 16 rows
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- label: GRAPHIC MODES
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value: |-
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Model 1 : 64 / 32 x 16, 128 x 48\
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Model 2 : 64 / 32 x 16 (semigraphic mode), 256 x 192 (4 shades of grey), 512 x 192 (monochrome)
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- label: COLORS
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value: |-
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Model 1: monochrome\
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Model 2: at least 4 colors
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- label: SOUND
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value: 1 channel
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- label: SIZE / WEIGHT
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value: 37.2 (W) x 23.8 (D) x 7.8 (H) cm
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- label: I/O PORTS
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value: |-
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Power Supply (DIN5), Paralell interface (DB26), Serial Interface (DIN5), Tape-recorder (DIN5, 500 baud)\
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Model 2 has an external disk drive connector (DB26)
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- label: OS
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value: 'Model 2 : MER-DOS, CP/M 2.2'
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- label: POWER SUPPLY
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value: +5v/2.5A, -5v/0.1A, +12v/0.2A
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- label: PRICE
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value: 160,000 Zloty (Poland, 1984)
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tabs:
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- photos
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- hardware
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- links
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forum_thread: 491
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photos:
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- title: MERITUM MODEL 2
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subtitle: ''
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text: ''
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image: /media/museum/photos/mera_meritum_system_s2.jpg
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- title: LEFT & RIGHT SIDES
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subtitle: ''
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text: ''
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image: /media/museum/photos/mera_meritum_bothsides_s1.jpg
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- title: KEYBOARD CLOSE-UP
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subtitle: ''
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text: Some keys have both the Latin and Cyrillic letters.
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image: /media/museum/photos/mera_meritum_keybcloseup_s1.jpg
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- title: REAR CONNECTORS
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subtitle: ''
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text: |-
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From left to right :
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• Power Supply DIN-5 socket\
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• Parallel DB25 connector\
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• Serial DIN-5 socket\
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• Floppy drive DB25 connector\
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• Tape-recorder DIN-5 socket (500 baud).
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image: /media/museum/photos/mera_meritum_rearside_s1.jpg
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- title: ELECTRONICS
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subtitle: ''
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text: The internal electronics is made of two superimposed cards linked together by three connectors
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image: /media/museum/photos/mera_meritum_inside_s1.jpg
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- title: BOTTOM CARD
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subtitle: ''
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text: |-
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The bottom card is the main board. East European and Japanese chips are mixed. All the standard logic circuits come from Eastern Europe.There is no RAM chips on this card, although provision is made for them.\
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**(1)** Z80 processor, marked '80 CPU'\
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**(2)** Character generator 2K ROM chip\
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**(3)** Tape recorder leads\
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**(4)** 7 x 2K ROM chips, made in Soviet Union. They hold the Basic interpreter\
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**(5)** One of the three connectors providing the link between the two cards\
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**(6)** The quartz is glued on the card. Notice also the unused Bus connector\
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**(7)** NEC 8255 PIA (Programmable Interface Adapter)\
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**(8)** Timer and I/O chips coming from Soviet Union
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image: /media/museum/photos/mera_meritum_bottomcard_s1.jpg
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- title: BOTTOM CARD CLOSE-UP
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subtitle: ''
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text: Processor and I/O chips.
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image: /media/museum/photos/mera_meritum_bottomcard_s2.jpg
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- title: ROM BANK
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subtitle: ''
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text: ''
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image: /media/museum/photos/mera_meritum_rombank_s1.jpg
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- title: TOP CARD
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subtitle: ''
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text: |-
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The top card holds the keyboard circuitry, the floppy drive interface and the RAM chips.\
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**(1)** 8 x 4164 chips hold the 64 KB user RAM\
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**(2)** A second 8255 PIA provides the floppy drive interface.
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image: /media/museum/photos/mera_meritum_topcard_s1.jpg
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hardware:
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- title: 5''1/4 DISK-DRIVES
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subtitle: ''
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text: Picture courtesy of [Kupa Zlomu](http://212.126.12.126/~mcadam/).
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image: /media/museum/hardware/mera-elzab_meritum2_disks.jpg
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- title: 5''1/4 DISK-DRIVES
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subtitle: ''
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text: |-
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Another bad picture... :-)
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Picture courtesy of [Kawior home pages](http://www.niuniek.republika.pl/kawior/html/speccy.html).
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image: /media/museum/hardware/mera-elzab_meritum2_disks_2.jpg
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links:
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- title: Dziennik Mi³oœnika Polskich Komputerów
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url: http://www.elwro.zafriko.pl/kat/mikrokomputery/mera_elzab_meritum_i
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text: This polish museum has some information (in polish) and some pictures
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oc_id: 497
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source:
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url: https://web.archive.org/web/20230201125733/http://www.old-computers.com/museum/computer.asp?c=497
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date: '2023-02-01'
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---
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This Polish computer was first introduced in fall 1983. As pretty much every sophisticated piece of hardware from the Eastern Block, it was copied from a western computer. The ROM is based on the [TRS-80 model II](/museum/tandy-radio-shack-trs-80-model-ii/), so the Meritum can be considered as a TRS-80 clone. It was mainly used in schools and is considered as the precursor of the polish computing industry as it was the first computer to be produced in Poland.
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In fact the Meritum is not entirely Polish but rather a miracle of the eastern block industry : the keyboard and case is polish, disk-drives made in Hungary (some sources say Germany) and memory from Bulgary. 8'' disk-drives are said to be the Robotron K6500 ones...
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The keyboard is quite special : left, right and down keys are situated on the right part of the keyboard whereas the up key is placed at the opposite left side !! Quite practical... Much weirder, two keys are blank !!
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The Meritum has 64 graphic symbols. The Basic takes 12k of the 14k ROM. It is a Tandy Basic modified to use polish letters (Model 2). Some keyboards have Cyrillic letters for the Soviet union instead of the Latin alphabet. The system uses a U880D microprocessor which is a East-German clone of the Z80.
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There are two models, the Meritum model 2 having more memory (48k RAM) and higher resolutions than the model 1. It can be connected to external disk-drives and have a built-in disk controller. It can use polish alphabetical signs and has a parallel port.
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The Model 1 which had no graphical resolution (only semi-graphic symbols), no colors, small memory and very high price, was not very popular and was considered obsolete even before being marketed !
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A Meritum III was released and shown on Poznan fair 1986, but apparently wasn't produced.
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Among planned but never created accesories were: network interfaces ( this was actually produced for the II model ), and a expansion graphics processor that would in these days be called nothing more than a graphics accelerator :) Unfortunately, Mera was forced to suspend the productions of Meritums in favor to computer terminals etc. The whole assembly staff of the Meritum line was five people, and East Germany could not meet the demands for the 5,25" disk drives that were needed for the Meritum II. Meritum was abandoned, as it couldn't compete with private imports of C64 and Atari computers.
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If you find some info or know more about the Meritum computers, please mail us.
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