website/content/museum/cromemco-system-i-ii-iii.md

---
title: Cromemco System I / II / III
categories:
- Computers
types:
- Professional Computer
origins:
- U.S.A.
years:
- '1976'
cpus:
- Z80
params:
  name: System I / II / III
  image: /media/museum/photos/cromenco.jpg
  company: /companies/cromemco
  company_name: Cromemco
  specs:
  - label: NAME
    value: System I / II / III
  - label: MANUFACTURER
    value: Cromemco
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: '1976'
  - label: CPU
    value: Z80
  - label: RAM
    value: 32 KB (up to 512 KB with a pagination mechanism)
  - label: ROM
    value: Unknown
  - label: TEXT MODES
    value: Unknown
  - label: GRAPHIC MODES
    value: 754 x 482 monochrome / 377 x 241 16 colors. A special video card was available with 3 video processors which allows the same resolutions but respectively with 8 and 4096 colors.
  - label: I/O PORTS
    value: 8 bit ADC or DAC, Centronics, Disk controller, S100 Bus, 21-card-slot
  - label: BUILT IN MEDIA
    value: Varies according the model
  - label: OS
    value: CP/M
  tabs:
  - photos
  - adverts
  photos:
  - title: THE SYSTEM ONE CS-1H
    subtitle: ''
    text: |-
      This system was based on the DPU Dual Processor Unit (68000 and Z80-A microprocessors board) that made the system *the equal of superminis ans mainframes in some area* (said the advert). The system was able tu run simultaneously CP/M (8 bits) and Cromix (16 bits) operating systems. Switching between the Z-80 and 68000 was automatically controled. Up to 2 MB of RAM could be installed in the case.

      Price: **$5495** with 256 KB of RAM and 780 KB of floppy storage.
    image: /media/museum/photos/cromemco_systeme1_cs1h_1.jpg
  - title: SYSTEM ONE, MAIN UNIT
    subtitle: ''
    text: ''
    image: /media/museum/photos/cromemco_systeme1_mainunit_1.jpg
  - title: THE CROMEMCO SYSTEM III
    subtitle: ''
    text: The box in the middle is the Central Processing Unit & A four 5.25" FDD (512 KB each). It has 32 KB RAM, the advertisement said "Its fast RAM memory is large - No danger of obsolescence from inadequate RAM capacity" !!
    image: /media/museum/photos/cromemco1.jpg
  - title: SYSTEM III OPENED
    subtitle: ''
    text: ''
    image: /media/museum/photos/cromemco_systeme3_opened.jpg
  - title: SYSTEM III WITH TERMINAL
    subtitle: ''
    text: Cromemco SYSTEM THREE with a CROMEMCO C-3102 CONSOLE and keyboard
    image: /media/museum/photos/cromemco_systeme3_withterminal.jpg
  - title: SYSTEM III REAR SIDE
    subtitle: ''
    text: ''
    image: /media/museum/photos/cromemco_systeme3_rearside.jpg
  - title: THE CROMEMCO PANEL PROM PROGRAMMER
    subtitle: ''
    text: The two PROM sockets are designed to copy PROMs.
    image: /media/museum/photos/cro_eprom.jpg
  - title: CARDS DIAGRAM
    subtitle: ''
    text: |-
      This diagram shows the range of S-100 cards Cromemco solded in 1982.

      **- 1 - CPU boards**\
      \- Dual processor (68000 + Z80)\
      \- Single card computer\
      \- Z80-A 4 Mhz.

      **- 2 - Memory boards**\
      \- 4 KB RAM\
      \- 16 KB RAM\
      \- 64 KB RAM\
      \- 16 KB PROM\
      \- 8 KB ByteSaver\
      \- 32 KB ByteSaver\
      \- 48 KB two-port\
      \- 16 KB two-port\
      \- Memory control unit

      **- 3 - Multiprocessing and network cards**\
      \- I/O processor\
      \- Quad Sync/Async ports\
      \- Serial / Parallel I/O\
      \- Networking interface\
      \- I/O off-line processor

      **- 4 - S-100 BUS**

      **- 5 - I/O interfaces**\
      \- Floppy disk interface\
      \- Analog interface\
      \- Hard Disk interface\
      \- Hi Resolution / Analog\
      \- Printer interface\
      \- 8-port parallel interface\
      \- General purpose interface\
      \- 4-port isolated interface\
      \- Dual Serial and Parallel ports\
      \- Wire Wrap card

      **- 6 - Color Graphics card**\
      \- High Resolution color graphics card
    image: /media/museum/photos/cromemco_systeme1_diagram_1.jpg
  adverts:
  - title: US ADVERT (1982)
    subtitle: ''
    text: ''
    image: null
  - title: UK ADVERT
    subtitle: ''
    text: UK advert from Personal Computer World magazine, October 1983
    image: /media/museum/pubs/cromemco_systeme1_pub_s1.jpg
  - title: AN ADVERTISING
    subtitle: ''
    text: I couldn't resist putting this photo here. The girl looks very happy, the ad said "The new System III can be provided with walnut floor cabinet".
    image: /media/museum/pubs/cro_bural.jpg
  comments:
  - author: Ian Yoch (USA)
    date: Sunday 27th November 2011
    text: |-
      My first job was with Cromemco (employee $58).\
      The Cromix system shared 16KB between the 8 banks of 64kB max memory, it had the OS. Bank 0 had ??kB memory and the whole OS, banks 1-8 had the user 64k with 16k disabled or 16kB memory cards offset to 16kB and higher. Also came out with a 48KZ memory card so that nothing was wasted.\
      Fast since a lot of stuff was Z80 assembly.\
      The real hot sw was the 32kB structured BASIC. It had everything and was all assembly, it was stuffed into 32kB of 2116 EPROMs! So fast the business apps were written using it as I remember. You could run interpeted or complie the code.\
      Oh, Cromemco also had the first C sw on a micro. I rememeber compiling a ''Hello'' program and it was an incredible 5kB!!! Talk about memory hog!! He he, the old days back when you counted Bytes...
  - author: Edward Kenny (Huntsville, AL (USA))
    date: Thursday 29th September 2011
    text: I upgraded a Cromemco System III in the early 1980''s for NASA. It used the MP/M O/S. We supported 6 users at one time with 6 terminals and 5 printers scattered among the secretaries for the division. I believe it had two hard drives. I believe there were 7 64KB memory cards. Each of the 6 users had 62KB of RAM dedicated to them. Wordstar was used by each secretary for word processing. It is amazing to think back how one Z80 CPU at 4MHz could support 6 people at one time each running Wordstar.
  - author: Peter Harding (UK)
    date: Sunday 1st May 2005
    text: Our Company used two Cromemco System IIIs and I bought an old Cromemco system personally. Both of the IIIs had twin 8" drives which eventually failed. We bought them in 1981/82 and kept them in use until about 1986/7 when we bought a Compaq 286 as a dedicated server (running Novell 2.0a.) with two Compaq PC/ATs as workstations running CP/M and MSDOS. The Cromemco systems had 4 16KB S100 ram boards and the other boards were processor, serial & parallel I/O & drive controller. Televideo terminals (monitors with attached keyboards) were used to interact with the system boxes. We ran CDOS (the Cromemco DOS) and CP/M as operating systems with Wordstar, Calcstar, Datastar and Supersort. I set up a rudimentary stock control and invoicing system using the application software. We also dabbled with an operating system called BOS and ran an accounting package under BOS. I also obtained a copy of Cromix which was a multiuser UNIX-like operating system but, without a hard disk, this was not
      very successful. I believe we still have the system boxes on a pallet at the back of our warehouse and at some stage (when I retire?) I'll try to get it all working.
  oc_id: 113
  source:
    url: https://web.archive.org/web/20230608161731/http://www.old-computers.com/museum/computer.asp?c=113
    date: '2023-06-08'
---

CROMEMCO was founded in 1974 by two Stanford Students, **Roger Melen** and **Harry Garland**, who lived in the **CRO**thers **MEM**orial Hall dormitory on the Stanford campus.\
Eventually CROMEMCO needed space to receive visitors, and moved out of the dorm to Mountain View, and incorporated in 1976. Early products were cards for the S-100 bus, as used by the [Altair](/museum/apple-iic/) and [IMSAI](/museum/imsai-8080/) computers.

These computers were built around the S100 bus. The S100 BUS was a standard (also known under the name IEEE 696) for connection on Zilog Z80 or Intel 8080 processors. A lot of S100 cards were available for the Cromenco systems.

Four Cromenco systems were available :

\- [System 0](/museum/cromemco-systeme-0/): Z80 A + RAM 64 KB + 2 floppy disk drives (390 KB each),\
\- **System I**: As system 0 + 1 hard disk (5 MB).\
\- **System III**: Z80 CPU, Dual 8" Persci electrically driven floppy drives, 64 KB RAM. It was S-100 bus, Multiuser, used MP/M operating system.

In 1982, Cromemco also introduced the CS-1H system using a dual processor board (Motorola 68000 and Z80) and offering 16 MB of address space.

For the moment, we don't know exactly the specific features for the Systems II and IV.

These systems ran under Cromix (the Cromenco Unix version). They could run under CP/M and CDOS too (CDOS is a CP/M like operating system). Several languages were developped especially for these computers : Fortran IV or a 16 K Z80 Basic wich was given as "one of the fastest and most capable. Full 14-digit precision".

<table> <tr> <td></td> <td>We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.</td> <td></td> </tr> </table>