View source for Engineering:IBM PC Convertible

{{Infobox information appliance
| name = IBM PC Convertible
| logo = 
| image = ibm-convertible.jpg
| caption = IBM PC Convertible<!-- include if image is not a logo -->
| developer = 
| manufacturer = 
| carrier = 
| family = 
| type = 
| generation = 
| releasedate = {{Start date and age|1986|04|02}}
| lifespan = 
| price = {{USD|2000|1986|round=-1}}<!-- this is price at initial release, not the current price. -->
| discontinued = {{End date and age|1989|08|07}}<ref>{{cite press |url=https://www-01.ibm.com/common/ssi/cgi-bin/ssialias?appname=skmwww&htmlfid=897%2FENUS189-107&infotype=AN&subtype=CA |title=IBM 5140 PC Convertible Products and Selected Features Withdrawal From IBM Marketing: Announcement Letter Number 189-107 |date=July 6, 1989 |publisher=International Business Machines Corporation |access-date=May 27, 2020}}</ref>
| unitssold = 
| unitsshipped = 
| media = 
| os = IBM PC&nbsp;DOS with custom icon-oriented shell interface<!-- operating system -->
| power = Battery: 9.6v/2400mAh (NiCd)<br>Power supply: 15 VDC, 2.7A.
| cpu = [[Company:Intel|Intel]] 8088 [[Central processing unit|CPU]] @ 4.77 MHz
| storage = Dual 720&nbsp;KB 3.5-inch floppy drives
| memory = 256&nbsp;KB of RAM (expandable to 640&nbsp;KB)
| display = Monochrome [[Color Graphics Adapter|CGA]]-compatible LCD screen.
| graphics = 80x25 (text), 640x200, and 320x200
| sound = 
| input = 
| location = <!-- GPS or Wi-Fi based -->
| controllers = 
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| camera = 
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| connectivity = 
| service = <!-- online service/s offered -->
| dimensions = 
| weight = 13 pounds (5.8 kg)
| topgame = 
| compatibility = 
| predecessor = [[Engineering:IBM Portable Personal Computer|IBM Portable Personal Computer]]
| successor = IBM  PS/2 L40SX<br>(IBM PS/2 note)
| related = 
| website = 
}}

The '''IBM PC Convertible''' (model 5140) is a laptop computer made by [[Company:IBM|IBM]], first sold in April 1986.<ref>{{Cite web|date=1986-04-02|title=CUSTOMER ANNOUNCEMENT SUMMARY - APRIL 2, 1986|url=https://www-01.ibm.com/common/ssi/cgi-bin/ssialias?appname=skmwww&htmlfid=897/ENUSC86-006&infotype=AN&subtype=CA&mhsrc=ibmsearch_a&mhq=announcement|access-date=2020-10-07|website=www-01.ibm.com|language=en-US}}</ref> The Convertible was IBM's first laptop-style computer, following the luggable IBM Portable, and introduced the [[Floppy disk#3½-inch floppy disk|3½-inch floppy disk]] format to the IBM product line.<ref>{{Cite book|last=Corporation|first=Bonnier|url=https://books.google.com/books?id=sgEAAAAAMBAJ&q=ibm%20convertible%20new%203.5%20inch%20floppy&pg=PA89|title=Popular Science|date=Feb 1987|publisher=Bonnier Corporation|language=en}}</ref> Like modern laptops, it featured power management and the ability to run from batteries.<ref name=":0">{{Cite book|last=Inc|first=InfoWorld Media Group|url=https://books.google.com/books?id=Xi8EAAAAMBAJ&q=ibm%20pc%20convertible&pg=PA48|title=InfoWorld|date=1986-08-18|publisher=InfoWorld Media Group, Inc.|language=en}}</ref>

It was replaced in 1991 by the IBM PS/2 L40 SX, and in Japan by the IBM Personal System/55note, the predecessor to the ThinkPad.{{Citation needed|date=October 2020}}

==Predecessors==
IBM had been working on a laptop for some time before the Convertible. In 1983, work was underway on a laptop similar to the Tandy Model 100, codenamed "Sweetpea," but it was rejected by Don Estridge for not being PC compatible. Another attempt in 1984 produced the "P-14" prototype machine, but it failed to pass IBM's human factors tests, especially after poor public reception of the display in the competing [[Engineering:Data General-One|Data General-One]].<ref name="strehlo19850617">{{cite news | url=https://books.google.com/books?id=FS8EAAAAMBAJ&pg=PA8 | title=The Chiclet Rule and the Green Dragon | work=InfoWorld | date=1985-06-17 | access-date=23 March 2016 | author=Strehlo, Kevin | pages=8}}</ref>

==Description==
The PC Convertible came in three models: PC Convertible, PC Convertible Model 2 and PC Convertible Model 3. The latter two were released in October 1987 and are primarily distinguished by their LCD panels. The original Convertible used a non-backlit panel which was considered difficult to read. The Model 2 lacked a backlight as well but upgraded to an improved [[Engineering:Super-twisted nematic display|supertwist]] panel, and the Model 3 included a backlight.<ref name=":1">{{Cite book|last=Inc|first=Ziff Davis|url=https://books.google.com/books?id=jE2OlZ9PkrkC&q=ibm%20pc%20convertible%20backlit&pg=PA168|title=PC Mag|date=1987-10-27|publisher=Ziff Davis, Inc.|language=en}}</ref> The other hardware specifications are largely the same for all three models.

The CPU is an Intel 80C88, the [[Engineering:CMOS|CMOS]] version of the [[Engineering:Intel 8088|Intel 8088]] [[Central processing unit|CPU]]. The base configuration included 256&nbsp;KB of RAM, expandable to 640 KB, dual 720&nbsp;KB 3.5-inch floppy drives, and a monochrome, [[Color Graphics Adapter|CGA]]-compatible LCD screen. It weighed just over 12 pounds and featured a built-in carrying handle, with a battery rated for 10 hours (4 in the backlit Model 3.)<ref name=":0" />

The first model was introduced at a price of $1,995, the Model 2 at $1,395 with 256K of RAM and $1,900 with 640K, and the Model 3 at $1,695 with 256K of RAM.

The LCD screen displayed 80x24 characters, but has a very wide aspect ratio, so text characters and graphics are compressed vertically, appearing half their normal height. The display is capable of 80x25 text and graphics modes of 640x200 and 320x200 pixels.

The PC Convertible has expansion capabilities through a proprietary [[Engineering:Industry Standard Architecture|ISA bus]]-based port on the rear of the machine. Extension modules, including a small printer and a video output module, were provided as plastic modules that snap into place. The machine can also take an internal [[Modem|modem]], but has no room for an internal hard disk. The concept and the design of the body was made by German industrial designer Richard Sapper.

Pressing the power button on the computer does not turn it off, but puts the machine into "suspend" mode, which will hold the machine's state as long as battery power lasts, to save on boot time. The CMOS 80C88 CPU has a [[Static core|static core]], which holds its state indefinitely by stopping the system clock oscillator, and can resume processing when the clock signal is restarted as long as it is kept powered. The system RAM in the Convertible is SRAM rather than DRAM, both for lower power consumption and less circuitry to fit into the cramped laptop case.

Pressing a lever between the two floppy drives just below the display detaches the entire screen from the unit. This feature allows the use of a full-size desktop monitor while at one's desk, an early forerunner of the "docking station" concept, and similar to Apple's PowerBook Duo.

==Reception==
The machine had difficulty in the marketplace and was seen as a poor value for money, since other laptops in the market had more built-in features, although it enjoyed some success with business users, who saw its battery life and portability as selling points.<ref>{{Cite book|last=Inc|first=InfoWorld Media Group|url=https://books.google.com/books?id=yzAEAAAAMBAJ&q=ibm%20convertible%20new%20floppy&pg=PA20|title=InfoWorld|date=1987-06-22|publisher=InfoWorld Media Group, Inc.|language=en}}</ref> Even after the release of the Model 3 in October 1987, which fixed some of the machine's issues, lack of built-in features remained a pain point. The parallel, serial and video ports all required adapters, while competing machines included these as integrated features.<ref name=":1" /> The Convertible was heavy, not much faster than the Portable it replaced, had no traditional PC expansion ports (such as [[Serial port|serial port]]s and a [[Parallel port|parallel port]]) without an add-on, and had a hard-to-read, oddly-shaped LCD screen. It also competed against faster portables based on the [[Engineering:Intel 80286|Intel 80286]] that offered optional hard drives, from companies such as [[Company:Compaq|Compaq]], and laptops from companies such as [[Company:Toshiba|Toshiba]] and [[Company:Zenith Data Systems|Zenith]] that were lighter and offered similar specifications, sometimes at half the price. The keyboard was also criticized for lacking several important keys.<ref name=":1" />

==See also==
* [[Engineering:IBM Portable Personal Computer|IBM Portable Personal Computer]]
* IBM PS/2 L40SX
* IBM PS/55note
* [[Engineering:History of laptops|History of laptops]]
* Convertible (computer)

==References==
{{Reflist}}

==External links==
* {{cite web | url = http://www-03.ibm.com/ibm/history/exhibits/attic/attic_013.html | title = IBM PC Convertible | work = IBM Archives | publisher = IBM | access-date = September 11, 2006}}
* {{cite web | date = November 26, 2003 | url = http://www.xs4all.nl/~fjkraan/comp/ibm5140/ | title = IBM Convertible 5140 | publisher = Oh no, not another computer museum! | access-date = September 11, 2006}}
* [https://www.oldcomputermuseum.com/ibm_5140.html IBM-5140 Convertible] and collection of old digital and analog computers at oldcomputermuseum.com
* {{Citation | url = http://vintage-laptops.com/?page_id=232&lang=en | contribution = IBM PC Convertible, 360 degree model | title = Russian Vintage Laptop Museum | type = museum}}

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{{s-bef|before = [[Engineering:IBM Portable Personal Computer|IBM Portable Personal Computer]] }}
{{s-ttl|title  = IBM Personal Computers }}
{{s-aft|after  = IBM PS/2 L40 SX }}
{{s-end}}

[[Category:Portable computers]]

{{Sourceattribution|IBM PC Convertible|1}}