Torch CX20

The Torch CX20 combined the company’s networked C-series computer with a D20 storage module containing a floppy drive and 20MB Winchester hard disk. Its 6502, Z80 and 68000 processors supported BBC software, CPN applications and Unix in one workstation.

The modular system was aimed at connected offices, laboratories and educational sites. Torchnet linked multiple workstations and storage resources, while the hard disk made the larger Unix environment practical.

Notable Features

• D20 module paired a 400KB floppy drive with a 20MB Winchester hard disk.
• Triple-processor system contained 544KB total RAM in a standard configuration.
• CX designation identified network support without the TX model’s additional telecommunications package.

Historical Significance

• A complete hard-disk configuration of Torch’s ambitious multi-processor Professional range.
• Showed how BBC-derived hardware could be developed into a serious networked Unix workstation.

Collector’s Notes

• The system’s several stackable modules and cables are easily separated over time.
• Hard-disk condition and original Unix or CPN media are central to restoration.

Specifications

Technical Information
Name	Torch CX20
Manufacturer	Torch Computers
Launched	Sunday, January 1, 1984
Country	United Kingdom
CPU	MOS 6502A, Zilog Z80B and Motorola 68000
Units Sold
Operating System	CPN and Unix System III; BBC software support
I/O	Serial, parallel, 1MHz bus and Torchnet networking
Keyboard	Professional detachable keyboard
Storage	400KB floppy and 20MB hard disk in D20 module
Sound	BBC-compatible sound
Graphics	BBC-compatible graphics with Torch software support
Display	Business monochrome or colour monitor
ROM	Torch MCP and CPN firmware
RAM	544KB total standard; expandable to 1056KB
CPU Speed	6502, Z80B and Motorola 68000