Compaq Portable | 1983
Compaq Portable
The Compaq Portable was one of the first portable computers and one of the first IBM PC-compatible systems. It was the first product from Compaq Computer Corporation, followed by the Compaq Portable series and the Compaq Deskpro series. The Compaq Portable was not just a "clone" of the IBM PC running Microsoft DOS. Its compatibility was so high that it could run the same version of MS-DOS and IBM PC software as the IBM PC itself, because Compaq reverse-engineered the IBM BIOS. The system was also a variation of the early "all-in-one" concept.
The Compaq Portable was released two years after CP/M-based systems like the Osborne 1 and Kaypro II. The Columbia Data Products' MPC 1600, the first IBM PC-compatible system, debuted in June 1982. Other systems like the Dynalogic Hyperion, Eagle Computer’s Eagle 1600 series (including the Eagle Spirit Portable), and Corona Personal Computers were also IBM PC lookalikes. Some of these companies were threatened by IBM for infringing on IBM’s BIOS copyrights, and they settled out of court, agreeing to reimplement the BIOS. Additionally, systems like the Seequa Chameleon, which used both MS-DOS and CP/M with 8088 and Z80 CPUs, were also developed. Most of these companies had previous experience in launching Zilog Z80-based computers with Digital Research's CP/M OS. Compaq recognized that they could utilize IBM PC components and license MS-DOS to other companies, with the aim of achieving full IBM PC and PC DOS software compatibility. However, Compaq was the only company to successfully resolve the issue of the BIOS by reverse-engineering it.
Other contemporaneous systems included the portable Commodore SX-64, which was the first full-color portable computer based on the popular Commodore 64 home computer and equipped with the 8-bit MOS 6510 (6502-based) CPU. However, the Compaq Portable series outsold these systems.
The Compaq Portable was announced for production and sale in November 1982 and first shipped in March 1983. The price of the model with a single half-height 5¼" 360 KB disk drive was $2,995 ($9,200 in 2023 dollars), and the model with dual full-height disk drives was $3,590. The unit weighed 28 pounds (13 kg) and could be stored in a case the size of a portable sewing machine.
IBM developed its own portable PC in response to the Compaq Portable, as its sales team needed to offer a similar machine to compete with Compaq.
Compaq sold 53,000 units in the first year, generating $111 million in revenue, a record achievement in U.S. business history. In the second year, the revenue grew to $329 million, and in the third year, it reached $539 million, setting another industry record.
The Compaq Portable had hardware nearly identical to the IBM PC, but it was housed in a portable case. Instead of using IBM's BIOS, Compaq used its own BIOS. Every Compaq Portable came with 128 KB of RAM and one or two double-sided 360 KB disk drives. Like the IBM PC, the Compaq Portable used only AC power and did not have a battery.
The system supported a hybrid mode between IBM MDA and CGA, with the former using an 80x25 text mode character set and the latter used for graphic modes. The built-in monitor used a 9x14 font, while external monitors used an 8x8 font. Users could switch between the built-in monitor and external monitors, and when using an external monitor, the graphics hardware functioned the same as the original Compaq Deskpro desktop computers.
Compaq used a "form-and-pole" keyboard supplied by Keytronics. This keyboard had a timing pad system, where the circuit board made contact when typing. While it was used in devices like the Tandy TRS-80, Apple Lisa 1 and 2, Compaq Deskpro 286 AT, some mainframe terminals, and Sun Type 4, this system suffered from poor contact issues over time due to natural wear. The CRT display also had a low refresh rate and prominent ghosting issues.
Compaq’s success was largely due to IBM using mostly off-the-shelf components for the PC and making full technical documentation available, as well as Microsoft maintaining the right to license MS-DOS to other computer manufacturers. The only significant challenge was the BIOS, as it contained IBM's copyrighted code. To resolve this, Compaq created a completely new BIOS, written in a clean-room (workalike) approach, capable of performing all the documented functions of the IBM PC BIOS.
Many other companies soon began selling IBM PC-compatible systems, but few achieved the level of software compatibility with IBM PCs that Compaq did, with most achieving only around 95% compatibility. Later, companies like Phoenix Technologies began selling reverse-engineered BIOS systems, increasing the level of compatibility.
The early portable models used Compaq DOS 1.10, which was nearly identical to PC DOS 1.10 but included a standalone BASIC that did not require the IBM PC's ROM cassette BASIC. However, a few months later, DOS 2.00, with support for hard disks and other advanced features, replaced the earlier version.
The initial portable models using DOS 1.x were similar to IBM PC models with 16 KB – 64 KB RAM, and their BIOS was limited to 544 KB of RAM with no support for expanded ROM, making it impossible to use EGA/VGA cards, hard disks, or similar hardware. After the release of DOS 2.x and the IBM XT, Compaq upgraded the BIOS. Although the portable models were not originally shipped with hard disks, users commonly installed them. In 1984, Compaq released the Portable Plus, a version with a hard disk, though it only had a single half-height floppy disk drive. The available hard disk capacities were 10 to 21 MB, but many had reduced usable capacity due to bad sectors.
In 1985, Compaq released the Portable 286, which was later replaced by the more compact Portable II a few months later. The Portable 286 used the same chassis as the original Compaq Portable, but with a 6/8 MHz 286 CPU and a high-speed 20 MB hard disk.
BYTE magazine reviewed a prototype and deemed the Compaq Portable a "clear winner" for its portability, cost, and high IBM PC compatibility. The reviewer tested IBM PC DOS, CP/M-86, WordStar, SuperCalc, and various other software packages, finding that all programs ran successfully, except for one game. PC Magazine also highly rated the Compaq Portable, reporting that all tested applications worked flawlessly. They praised its "rugged" hardware design and clear display, concluding that it was "definitely worth considering" for anyone looking to run IBM PC software.
Subsequent Models
- Compaq Portable PlusReleased in 1983, the Compaq Portable Plus was an upgrade of the original Compaq Portable, replacing the floppy disk drive with a hard disk. The logo and badge also changed from silver to gold. Independent computer stores had already been modifying earlier models to add hard disks, and Compaq saw this as an opportunity to capture lost revenue.
- Compaq Portable 286The Compaq Portable 286 was Compaq’s version of the IBM PC AT, featuring the original Compaq Portable chassis, a 6/8 MHz 286 CPU, and a fast 20 MB hard disk.
- Compaq Portable SeriesThe Compaq Portable machines began the Compaq Portable series. The Compaq Portable II was a smaller version of the Portable 286, with limited upgrade options and slower hard disk speeds, but at a lower price. Later models included the Compaq Portable III, Compaq Portable 386, Compaq Portable 486, and Compaq Portable 486c.
