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O > OLIVETTI  > M20   


In 1972, Olivetti established in the U.S.A. (Cupertino), the Advanced Technology Centre (ATC), a research centre specialized in new technologies and office automation equipment design. During ten years the centre designed Olivetti typewriters, calculators, photocopiers, etc.... In 1980, the first Olivetti computer took form in Cupertino, and the M-20 computer was launched in March 1982. More than 50,000 units are estimated to have been shipped in the first year.

The M20 was one of the very rare computers based on the Zilog Z8000, a 16 bits microprocessor very close to its 8 bits big brother the Z80. Like most of the computers designed before the IBM PC era, the M20 offered technical choices which made it totally incompatible with the rest of the micro world.

The first proprietary M20 operating system, called PCOS (Professional Computer Operating System) was also very particular and didn't allowed files to be exchanged with other systems. Hopefully, MS-DOS V2.0, CP/M-86 and CP/M-80 would be later adapted to the specific M-20 hardware. Moreover, front of this compatibility problem, Olivetti developped a coprocessor board based on the 8086 chip, which offered M20 owners access to IBM PC software.

The M20 came with a 12'' monochrome or colour custom built monitor. The international version had a grey plastic case, the Italian version had a brown one.

Please consider donating your old computer / videogame system to or one of our partners from anywhere in the world (Europe, America, Asia, etc.).


TJ, the price was around $5000 when it came out in 1982. Used M20s appear from time to time in eBay (Europe) for 200-300 depending on the conditions. A M20/DATEV was sold yesterday for 65 EUR in Germany. What is your configuration?

Sunday 14th May 2023

I have a brand new Olivetti L1 M20 brand new never used from a smoke free home, it is still in its original box with manuals and softwares. I was doing a search on how much a computer like this now a days is worth, and stumbled on this page, it’s part of an instate inheritance. I did see one at a price of $5400.00 not sure if it’s an error or if that’s the original price listed when Olivetti came out with it. Any info would be most appreciated. Thanks for reading. TJ

Tuesday 9th May 2023
TJ  (Canada)

Hello, I have just recovered a complete M20 with printer (pharmacy management application from 1980). I have the PCOS, BASIC, ISAM and Peripheral I/O manuals. I am looking for Disk 5''1/4 PCOS complete (L1.M20 PCOS-8000 Rev. 1.3d) Cordially

Friday 18th November 2022
Michel BURTE (France)


TYPE  Professional Computer
YEAR  March 1982
KEYBOARD  Full-Stroke 120 keys with numeric keypad
CPU  Zilog Z8001
SPEED  4 Mhz
RAM  128 KB expandable to 512 KB
TEXT MODES  80 columns x 25 lines
GRAPHIC MODES  512 x 256 pixels in 4 colours maximum
COLORS  4 or 8 with RAM extension board
SOUND  Beeper
SIZE / WEIGHT  42.5(W) x 51.4(D) x 15(H) cm. Weight: 10.5 Kg.
I/O PORTS  1 x RS-232 port, 1 x RS-1232C enhanced serial port, 1 x custom monitor connector, 1 x Parallel printer port
BUILT IN MEDIA  2 x 160, 320 or 640 KB 5.25'' F.D. drives
or 1 x F.D. drive + 1 x 11.25 MB Hard disk
OS  PCOS, CP/M8000, MS-DOS (with the APB 8086 card)
POWER SUPPLY  Built-in power supply
PERIPHERALS  128 KB memory card, Intel 8086 microprocessor card, IEEE-488 card
PRICE  $5400 (2 x F.D. version)

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