IBM RT/PC

Oh, well. At least they tried harder with the RS/6000!

	+ Can be accompanied by a Floating-Point Accelerator (FPA) board with a National Semiconductor NS32081 FPU @ 10 MHz (optional)
* Advanced Processor Card @ 10 MHz with a built-in Motorola 68881 FPU @ 20 MHz
	+ Can be accompanied by an Advanced Floating-Point Accelerator (AFPA) board based around the Analog Devices ADSP-3220 FP multiplier and ADSO-3221 FP ALU
* Enhanced Advanced Processor Card @ 12.5 MHz

### Storage

40 to 70 MB hard drive (upgradeable to 300 MB)
 1.2 MB 5.25" floppy disk drive
 IBM 6157 streaming tape drive

### Graphics

Resolution depending on display:* 720×512
* 1024×768

IBM 5080 or 5085 graphics processor (optional)

### Connectivity

Token ring network adapter
 10BASE2 Ethernet adapter
 x8 ISA slots

### Input

I/O provided by ISA slots

The **RT/PC** (short for **RISC Technology Personal Computer**), codenamed **032** during its development, was a family of workstation computers first released by IBM in January 1986.

It was IBM's first commercialized computer product to be based on a RISC (Reduced Instruction Set Computing) architecture.

The system's proprietary ROMP (short for **R**esearch **O**PD **M**icro**P**rocessor) CPU was based on the pioneering technologies that were implemented in the experimental 801 minicomputer, which was developed by IBM Research.

The RT/PC was produced in two form factors; the 6150 (floor tower) and the 6151 (desktop).

## Why it had Failed and was Crummy

1. IBM had **little to no faith** in the RT/PC, so their support for it was quite lacking.
2. The RT/PC, because of its name, had lead people to believe that it was part of the Personal Computer line. Heck, IBM even thought that it was a high-end PC!
3. The sales commission structure that IBM gave the RT/PC was far too similar to those for the sale of a standard PC. With typically configured systems selling for up to $20,000 USD (around $20,335.24 by today's rates), it proved to be a hard sell, and the lack of any reasonable commissions lost the interest of IBM's sales force.
4. Software suppliers were slow to adopt the RT/PC, due to a lack of software packages, and IBM's lackluster support for the AIX operating system, along with sometimes unusual changes from the traditional de facto UNIX standards.
5. Its performance, when compared to its contemporaries, **wasn't all that hot**.
6. Its floating-point capabilities were **abysmal**.
	* This was further scandalized by the discovery of a bug within the floating-point square root routine.
7. The RT/PC's performance, combined with its price ranges, meant that it had a poor price-performance ratio.

## Redeeming Qualities

1. The RT/PC did well as an interface system between IBM's larger mainframes, due to its SNA and DS support, as well as some of its point-of-sale terminals, store control systems, and machine shop control systems.
2. It found a home mostly in the CAD/CAM and CATIA markets, with some inroads into the scientific and educational areas, especially after the announcement of AOS (an IBM port of 4.3BSD UNIX for the RT/PC) and substantial discounts for the educational community.
3. The RT/PC had forced an important stepping-stone in the development of the X Window System. A group at Brown University in Providence, Rhode Island had ported X version 9 to the RT/PC. Complications reading unaligned data on the system necessitated an incompatible protocol change, leading to the introduction of X version 10 in late 1985.
4. The RT/PC innovated the use of a microkernel to control the keyboard, mouse, display, disk drives, and network, in the form of the Virtual Resource Manager (VRM), which allowed multiple operating systems to be booted and run at the exact same time. One could "hotkey" from one OS to the other via the Alt+Tab key combination, and each OS, in turn, would gain possession of the keyboard, mouse and display.

## Trivia

* The RT/PC found usage in the backbone of the Internet's predecessor, the National Science Foundation Network (NSFNET). From July 1988 to November 1992, the NSFNET's T1 backbone network had used routers built from multiple RT/PC systems (typically nine at a time) that were interconnected by a token ring LAN.
* The ROMP had the distinction of being the very first commercialized RISC-type CPU.
* The AIX operating system was IBM's second foray into UNIX, their first being the PC/IX operating system for the PC.
* The IBM 6152 Academic System's RISC Adapter Card uses the ROMP-C, an improved version of the ROMP based on 1μm CMOS technology that went on to be used in later models of the RT/PC series. The RISC Adapter Card also allows the 6152 to run ROMP software that was compiled for AOS.

## External Links

* Wikipedia article
* IBM RT/PC at Old-Computers.com
* IBM RT 6150 at GradyOwens.us
* IBM announcement letter no. 186-006