website/content/museum/ohio-scientific-c2.md

title, categories, types, origins, cpus, params

title	categories	types	origins	cpus	params
OHIO Scientific C2	Computers	Professional Computer	U.S.A.	6502	name image company company_name specs tabs forum_thread photos oc_id source C2 /media/museum/photos/ohioscient_c2_system_1.jpg /companies/ohio-scientific OHIO Scientific label value NAME C2 label value MANUFACTURER OHIO Scientific label value TYPE Professional Computer label value ORIGIN U.S.A. label value YEAR Unknown label value BUILT IN LANGUAGE None label value KEYBOARD Depending on the video terminal used label value CPU 6502 label value SPEED 1 MHz. label value RAM 48 KB (Depends on the configuration) label value ROM Unknown label value TEXT MODES 80 chars x 25 lines (Standard video terminal) label value SOUND No sound label value I/O PORTS Serial label value BUILT IN MEDIA 2 x 8'' 275 KB floppy drives label value OS OS-65U label value POWER SUPPLY Built-in power supply unit label value PERIPHERALS Various OSI cards label value PRICE Unknown photos 820 title subtitle text image KEYBOARD /media/museum/photos/osi-c2_keyboard.jpg title subtitle text image INSIDE **(1)** 6002 CPU board. Also features a floppy disc controller and serial port\ **(2)** 16 KB RAM boards\ **(3)** D&N Micro Products IO-1600 board that, when fully populated, had 8 KB of additional RAM, a Parallel Centronics printer port, a Diablo parallel printer port, four RS-232 serial I/O ports and one RS-232 serial printer port with handshaking /media/museum/photos/ohioscient_c2_inside_1.jpg title subtitle text image FD UNIT /media/museum/photos/ohioscient_c2_fdunit_1.jpg title subtitle text image DEMO DISK General menu of the demonstration disk delivered with the operating system. /media/museum/photos/ohioscient_c2_samplescreen_1.jpg 839 url date https://web.archive.org/web/20230601180919/http://www.old-computers.com/museum/computer.asp?c=839 2023-06-01

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. [4] 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.

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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.