Tandy TRS-80 Model 4p
Tandy TRS-80 Model 4p
[Vin120]
The TRS-80 Model 4P was one of the earliest truly portable microcomputers offering full desktop capabilities with dual built-in floppy drives, integrated screen, and keyboard in a single transportable unit weighing about 26 pounds. It bridged the gap between desktop and portable computing, maintaining backward compatibility with the popular TRS-80 Model III and access to numerous CP/M applications, effectively enabling professional mobile computing for the first time. It was praised for its combination of power and portability, marketed as “full desktop power, anywhere,” though its weight made it relatively a “luggable” rather than a lightweight portable by modern standards. Despite being well-engineered and favored by traveling professionals, it saw limited commercial success. Its place in history marks an important step in the evolution from home/desktop microcomputers toward compact laptops.
- Manufacturer: Tandy Corporation (Radio Shack)
- Type: Luggable Computer
- Release Date: 1983
- Cost at release: $1,799 (CAD ~$6,200 adjusted for inflation)
- MIPS: 0.5 (500 KIPS)
Hardware Specifications
- CPU: Zilog Z80A running at 4 MHz, with some upgrades supporting 6.144 MHz (Hitachi HD64180/Z180).
- Memory: 64 KB of RAM, expandable to 128 KB, with some modifications supporting up to 384 KB using additional memory boards.
- Video Display: 9-inch green monochrome CRT monitor with an 80×24 character text display.
- Storage: Dual built-in 5.25-inch floppy disk drives (184 KB each), with some external mods for additional drives.
- Weight: Approximately 26 pounds (11.8 kg).
- Additional features: Built-in speaker for simple sound; compatibility with TRSDOS and CP/M; external connector options for peripherals, including modem and serial ports.
Operating System & Programming Languages
- Operating System: TRSDOS 6, an enhanced version of the TRS-80 Disk Operating System developed by Logical Systems and compatible with LDOS 6.00. It also supported CP/M (Control Program for Microcomputers)
- Supported Languages: Microsoft 5.0 BASIC (included with the system), Zilog Z80 Assembly language, and via CP/M: Pascal, COBOL and Fortran
Notables
- The Model 4P was the first portable TRS-80 with built-in dual 5.25-inch floppy drives and a full 80×24 character display, distinguishing it from earlier limited-display portables.
- Despite being described as a “smashing success” by InfoWorld in 1983 for its “carefully thought-out mechanical design” and “outstanding product at an excellent price,” it was commercially unsuccessful and discontinued by early 1985.
- Tandy acknowledged that “transportables just weren’t moving well for any company that also sold a desktop version” when explaining the discontinuation
- Represented one of the earliest attempts at “full desktop power, anywhere” computing, bridging desktop and portable computing eras.
Donated by: Dr Arlen Michaels
