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IBM 5140

USA 1986


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The IBM 5140 - The PC Convertible. IBM's first laptop

Developed in 1985 and put on the market in 1986 as IBM's first true "Laptop" type computer, although since it weighed almost 12lbs, it certainly wasn't something you would want to operate on your lap. But for 1986, it was a technological breakthrough and offered the ability to run without the need to find a power outlet. For a portable it was very powerful at the time. The machine was powered by a low-power 80C88 processor, designed to stretch the battery time to it's maximum.


A well equipped machine and it would have to be to sell a computer with an older processor in it and no hard drive.

These were probably left out for 2 reasons:

  • the cost of putting them into a smaller case would have made them too expensive to sell and
  • the battery probably would have lasted 10 minutes.

It originally sold for $3500 which was not bad considering that the AT and XT/286 models sold for almost twice that around the same time.

It is not easily upgradable because it does not have expansion slots, but an optional printer can be attached to the back giving a very clean appearance. Space saving ideas included using 3.5" drives to save space and removing the expansion slots to allow the board to fit into its small shell.(1)

The dimensions of the LCD appeared to be unpractical but allowed to see a quarter of a page. The LCD technology meant the next step in the evolution and the IBM 1540 is one of the tipical examples of that evolution, but for a stiff price.(2)



CPU: intel 8088
CPU speed 4.77Mhz
motherboard RAM: 256Kb
maximum RAM 512Kb
number of sockets  
minimum speed 4.77
ROM 64Kb
L1 cache  
L2 cache  
data path  
slots none
Serial Ports 1
Parallel Ports 1
Floppy 2 x 3,5" 720KB
HD no
Monitor built in 80 x 25 Chars 640 x 200 pixels
Sound Output beeper
Sound Input no


Type ID
power 110V / 220 V
Weight appr 6 KG (12 pounds)
Min System Software  
Max System Software
OS / software MS DOS 3.x
Input devices keyboard
introduced developped 1985, on the market 1986
terminated 1987
initial price 3500 USD



Release history

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Go Back Last Updated on 16 December, 2003 For suggestions please mail the editors 

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