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From truck to lap: how ‘portable’ computers evolved over time


In the advent of the digital age, it was hardly evident that a computer of over 3kg (6.6 lbs) will be called 'large' mere decades later. Before science created the means to fit a computer in a pocket, a 'portable' computer was something only a truck could move.

The key reason why our digital devices got smaller and faster at the same time is the transistor. The transistor is a semiconductor that provides an output of 0 or 1, allowing for the computer to, well, compute. More transistors mean more power.

For example, a legendary Zilog Z80 microprocessor, released in 1976, had 8,500 transistors. In comparison, a modern CPU like Apple's M1 has around 16 billion transistors. No wonder RadioShack's TRS-80, a legendary computer that got part of its name for using the Z80, could never compare to modern devices in terms of power.

Other factors notwithstanding, it'd take 1.8 million Z80's to replicate the M1. Even if the Z80 weighed 1 gram, 1.8 million of those would weigh 1.8 tons (1.9 US tons).

Now, the problem with the first computer devices, made in the '50s, was that there still were no integrated circuit boards with our beloved transistors. Computers relied on vacuum tubes to carry out various calculations.

Even though a novelty at the time, vacuum tubes were nothing but small in any modern sense. That made the first computer huge and as movable as a large library. However, harnessing the power of fast computation proved more important than obstacles like weight and lack of technology.

DYSEAC (1954)

Original DYSEAC van trailers. One trailer housed a computer while the second one provided power. A human for scale. An excerpt from a YouTube video.

Built by the National Bureau of Standards for the US Military, DYSEAC might be the first computer to be specifically made to be moved from one place to another. Calling it 'portable' would be something of a stretch, as the device weighed around 20 tons and took two trailer vans to transport.

The first van carried the computer's brain, while the second provided the device with the 12 kW power needed to survive. Or, to put it simply, a van housed a computer, while another one served as its battery.

No wonder, as the computer was made of 900 power hungry vacuum tubes together with thousands of diodes that accompanied it.

MOBIDIC (1959)

An outline of the MOBIDIC module. An excerpt from a YouTube video.

Short five years have passed, and a somewhat 'smaller' device was delivered to the military by Sylvania, a now-defunct electrical equipment manufacturer. Even though a few tons lighter than the DYSEAC, MOBIDIC also consisted of two trailers, with the second providing necessary power.

Aptly named after a legendary sperm whale Moby Dick, the device's name was an acronym for 'MObile DIgital Computer.' The key innovation that allowed for a smaller size were transistors (32,000 of them), alongside diodes and magnetic cores.

US Army official explains the working of the FIELDATA project. An excerpt from a YouTube video.

MOBIDIC was part of a military FIELDATA project. Smaller LOGIPAC and BASICPAC installations that fit inside a military truck.
Engineers developed multiple 'portable' computers over the '60s, yet with microprocessors not yet invented, devices could not shrink in size. However, there were attempts as Digital Equipment Corporation (DEC) advertised its 1965 PDP-8 computer as fitting on the back seat of a convertible Volkswagen Beetle.

IBM 5100 (1975)

IBM 5100, one of the first computers, made to be used on the move. Image posted by u/Sherry_Haibara.

Real change happened with the start of the '70s, as Intel released the first actual microprocessor, the 4004, with 2,300 transistors in its capacity. Manufacturers of personal computers will take advantage of that, flooding the market with truly small desktop devices by the end of the decade.

The first somewhat portable computer to come out of the microprocessor era was the IBM 5100, released in 1975. The device weighed 25 kg (55 lbs), which allowed for swiffer transportation with a specially designed suitcase. A feather, compared to a couple of vans in the previous decades.

IBM 5100 with a software tape in the slot. Image posted by u/TheGamerguy.

The 5100 was only a second portable computer IBM made, with the first being IBM 1401, a truck-based 'portable' computer for the military. It was equipped with a keyboard, display, tape drive, and software. Unlike modern computers we'd consider portable, the 5100 had no internal battery and was powered via a wall socket.

Different configurations of the computer cost close to $20,000 ($100,000 in 2021) with the cheapest sold for around $9,000 ($45,400 in 2021).

Xerox NoteTaker (1978)

The Xerox NoteTaker, the prototype computer that inspired the first commercially successful portable computer. Empty slot on the right was meant to host a mouse. Image source.

History shows that Xerox was good at influencing what happened in the future of computers without actually taking part in the transformation.

Similar to Xerox Alto, which caused Apple to develop a graphic user interface (GUI), Xerox NoteTaker influenced later hits in portable computing while the NoteTaker itself remained a prototype.

The computer was equipped with a keyboard, mouse, floppy disk drive, monochrome display, and a rechargeable battery. The keyboard served as a lid to cover the screen of the device.

Only a handful of prototypes were ever made but it is estimated that the computer would have cost around $50,000 ($208,300 in 2021).

Osborne 1 (1981)

A close up of the Osborne 1. A carrying handle was installed on the back of the device with 'closed' keyboard facing the ground. Image posted by u/jmetal88.

Inspired by the NoteTaker, Osborne 1 is the first commercially successful portable computer. Weighing 11 kg (24.5 lbs), it was tiny for the era. Osborne 1 was relatively cheap, with a price tag of $1,795 ($5,360 in 2021), 38 times cheaper than Xerox's prototype, and eight times more affordable than IBM 5100.

The computer was equipped with a Z80A CPU and had 64K RAM and 4K ROM. Since it was released a month before the IBM PC rocked the world, it wasn't IBM PC compatible. 

It had a tiny 5-inch CRT screen and a detachable keyboard, but lacked a battery, meaning that users had to plug it into a wall socket at its release. Later models included a battery that Osborne advertised to provide an hour of runtime.

A different angle of the Osborne 1. Image source.

The company sold 11,000 units in the first eight months after release, and sales topped 125,000 units in 1982. The device's commercial success attracted competitors like Kaypro II and Compaq Portable.

Osborne has entered the business lexicon with the term 'Osborne effect.' The company tanked after announcing a release of an updated model, the Osborne Executive. 

Sales crashed as customers stopped getting the Osborne I, hoping to get the updated model. Since the announcement was meant as a PR campaign and not even a prototype was ready, the company went bust in 1985, only four years after hitting sales worth $1 million.

GRiD Compass (1982)

GRiD Compass computer aboard the Space Shuttle. Astronaut John O. Creighton holds the device. Image source.

Unbeknownst to its creators, The Compass was a very early taste of where the portable computer industry was to head for decades to come. Released in 1982 by GRiD, the device was the first clamshell (flat screen covering the keyboard) laptop in production.

When it was released, the device was very light, weighing 5 kgs (11 lbs). However, the Compass was not meant for everyone. Housed in a magnesium case and stuffed with powerful innards, the device cost $8,150 ($22,900 in 2021).

A different angle of the GRiD computer. Image source.

GRiD sold the computer with a custom-made CCOS operating system, Intel 8086 CPU, and 340 KB of magnetic bubble memory.

Strong built quality made the computer a lucrative option for NASA and the US military. Compass was aboard several of the first Space Shuttle missions.

Compaq Portable (1983)

The first Compaq Portable computer, among the first fully IBM PC compatible devices outside of IBM product line. Image posted by u/ShittyExchangeAdmin.

The first portable computer made by Compaq was also among the first to be fully IBM PC compatible. The computer ran on MS-DOS with a reverse-engineered BIOS, making it the first legal PC clone. Overtaking IBM's architecture allowed the device to offer users interchangeable software between any IBM desktop and the Portable.

IBM PC compatibility made the device very attractive since IBM PCs were the most popular desktop computers at the time.  

The device ready for transportation. Image posted by u/ShittyExchangeAdmin.

Weighing 13 kg (28 lbs), the Portable was heavier than Osborne 1, but unlike the latter, Compaq's device boasted a 9-inch screen and Intel 8088 CPU, and a 10MB hard drive.

In the first year of its release, over 53,000 units were sold, making for $111 million in sales. At the time, that was a record for revenue on a single item for any American business.

NEC UltraLite (1988)

NEC UltraLite computer was among the first to be dubbed 'notebook'. Image source.

It's no coincidence our list of 'portable' computers ends with the NEC UltraLite. The reason is in the picture – aesthetics aside, the device is hardly distinguishable from modern laptops.

Moreover, the computer weighed only 2 kgs (4.4 lbs), not far from what a modern laptop weighs. NEC made the computer fit the parameters of an A4 size sheet of paper, ushering in the term 'notebook.'

The first device in the Compaq LTE series popularized the term 'notebook' to describe a portable computer. An excerpt from a video.

However, UltraLite was not perfect – poor connectivity, lack of a hard drive, and a hefty price of $5,000 ($11,400 in 2021) did not allow the device to become popular.

Less than a year later, however, Compaq introduced the LTE series, an A4-sized clamshell-style laptop. Avoiding NEC mistakes, Compaq cemented the term 'notebook' in the mainstream and popularized the clamshell design, shaping the way laptops look for years to come.


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