Little information about this C2 system composed of a computer case and a separate floppy drives case.
The system pictured is a C2-OEM-4. [OEM] means it could be bought by other computer companies that could put their own brand label on the case.  means dual case version.
The main system was based on an 8 slot backplane (ref. 580), a 6502 processor board, along with a floppy disc controller and a serial port for the video terminal (ref. 505), and 3 x 16 KB static RAM boards (ref. 520). Ohio Scientific and various third companies provided several additional Memory and I/O boards for this system.
The floppy case had two Siemens single sided 8" 275 KB drives. With single sided drives user could copy to both sides of the floppy by removing the disk, turning it over and use the back side.
OSI delivered a specific operating system called OS-65U along with Business BASIC, a powerful BASIC interpreter, and various demonstration programs.
Thanks to Dan Schwartz for this additional information:
There were a variety of C2-series computers: The C2-4P and C2-4P MF (mini-floppy), the C2-8P and C2-8P DF (dual floppy), and the C2-OEM, which usually came in a single, longer case containing both 8" floppy disks and the CPU and backplane.
The C2-4P was renamed C4P when they added wooden sides to the case. The computer shown looks like the C2-8P DF, but the stated C2-OEM-4 designation could easily be correct. C2-OEM computers were set up to use a serial terminal, rather than an internal video board (producing a rough approximation of NTSC video) and "polled"(software-scanned) keyboard.
OSI was said to be the first company to offer microcomputers with hard drives, starting in 1977. Those drives were huge 14" monsters that took two men to lift!
OSI's two operating systems - OS-65D and OS-65U - both used heavily modified versions of what was originally the same version of Microsoft BASIC. In 65U, the business OS, there was no clear separation between the BASIC and the OS kernel; in 65D, the home-oriented system, there was.
OSI's floppy disk system was unique in that it used a serial port (ACIA) chip to read and write data to the disk. Every byte of data on the floppy actually had a start bit, a stop bit, and (under 65D) a parity bit. 65U programmed the hardware differently than 65D, so the two operating systems could not read each others' diskettes, although 65U included a limited utility to read raw sectors from 65D diskettes.
While I no longer have my OSI computers, I do still have a 12" black-and-white TV that was modified by OSI to work as a monitor, by adding A/V inputs, which normal TVs of the era did not have.
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.
I still have a C2-OEM. I have a Televideo terminal and a NEC Spinwriter printer for it. The C2-OEM I have is in a single case with dual 8" floppies. I have added memory and a printer card. I still have the OS 65D Tutorial and OS manual, and I may even have the full schematics. Have not started it up for years. In 2000, I took it to a vintage computer fair and ran Adventure on it. I would have to take it out of the attic to do an inventory of the cards.
Wednesday 12th September 2012
Simon Favre (USA)
This was my first serious computer (I started with TRS-80) which I bought in Boston in 1980 or 1981 (I think). I did a lot of work with this guy and even earned a living with it here on the downeast coast of Maine for several years.
It is a C2-OEM with 1 6502 cpu, 2 8" disk drives, and a serial port for a terminal (Hazeltine model ??, long gone) and a long parallel cable for my old Centronics tractor feed(also long gone).
Friday 18th December 2009
Jim Cummins (USA)
I purchased and used an Ohio Scientific in 1978 for personal and business purposes. Here is a partial list:
C8P DF GT Microprocessor - 6502C 4Mhz. (GT option) Ram - 48k 150ns. (GT Option) Disk - 2- 8" floppies each 170k I/O Video Board 64 x 32 Colors 1-RS232 Port (Software addressable to 2 connectors) Sound Output Home Security Interface BSR Remote control Hi Speed DAC C8P-DF-48k 2 Joystick Inputs GT Option
Expansion Serial RS232 Board CS-10-2 48 Line Parallel I/O CA-21 D/A, A/D CA-22 16 Channel input multiplex to one A/D 2 D/A 6 TTL Input 2 TTL Output
Serial Terminal AC-07C Haziltine 1420 Total Price $7,815.00
Lots of software. OS-65D V3.2, OS-65U V1.2, HC-1, HC-2,Graphics 1, Plot Basic, DAC1,PD 1-2, ED 1-4, BD 1-3, GD 5-10, WP6502U, WP3-2, WP3-1, OS-DMX, OS-Inventory, OS-DMS, OS-65U V1.42 - CD74 CD-36 MOS for Business, Demo Disk, Customer Demo, Dealer Demo.
I used the system for word processing and BASIC development for the company I worked for. I programed a customer equipment reception, tracking, and billing system. This required hacking the OS to remove the ''LF'' at the end of each write to the serial terminals so the text could be kept at the same location and be updated. Great fun.
I sold this system to my nephew in 1984. I think he still has it in storage. Don''t know.