Editing IBM 5100

{{Short description|Portable computer released by IBM in 1975}}
{{use mdy dates|date=July 2021}}
{{use American English|date=July 2021}}
{{Infobox information appliance
| name         = IBM 5100
| image        = IBM 5100 - MfK Bern.jpg
| caption      = The IBM 5100 Portable Computer
| manufacturer = [[IBM]]
| type         = Professional Computer
| releasedate  = {{Start date and age|1975|09}}
| discontinued = 1978
| price        = From $8,975 to $19,975
| connectivity = 
| lifespan     = 
| unitssold    = 
| media        = 
| os           = <!-- operating system -->
| input        = [[Keyboard (computing)|Keyboard]]
| camera       = 
| power        = 
| cpu          = [[IBM PALM processor]] clocked at 1.9&nbsp;MHz
| storage      = 
| memory       = 16–64&nbsp;KB [[random-access memory|RAM]] (with 16&nbsp;KB iterations)<br />32–64&nbsp;KB [[read-only memory|ROM]]
| display      = 5-inch CRT
| graphics     = 64x16 characters
| audio        = 
| service      = <!-- online service/s offered -->
| dimensions   = 
| weight       = {{convert|25|kg|lb|abbr=on}}
| touchpad     = 
| predecessor  = 
| successor    = [[IBM 5110]]
| related      =
}}

The '''IBM 5100 Portable Computer''' is one of the first [[portable computer|portable computers]],<ref>{{cite news |newspaper=[[The New York Times]]|url=https://www.nytimes.com/1975/09/10/archives/ibm-corp-introduces-a-50pound-computer.html|title=I.B.M. Corp. Introduces A 50-Pound Computer|date=September 10, 1975}}</ref> introduced in September 1975, six years before the [[IBM Personal Computer]], and eight before the first successful [[IBM compatible]] portable computer, the [[Compaq Portable]]. It was the evolution of a prototype called the SCAMP (Special Computer [[APL (programming language)|APL]] Machine Portable) that was developed at the IBM Los Gatos Laboratory and Palo Alto Scientific Center in 1973. Whether considered evolutionary from SCAMP<ref name="Timeline of Computer History">{{Cite web |title=Timeline of Computer History|url=http://www.computerhistory.org/timeline/?category=cmptr|access-date=May 7, 2014|publisher=Computer History Museum}}</ref> or revolutionary, it still needed to be plugged into an electric socket.<ref name=IBM5100.Wired>{{cite magazine |magazine=[[Wired (magazine)|Wired]]|url=https://www.wired.com/2013/05/ibm-5100-tech-time-wrap/|title=Tech Time Warp of the Week: The 50-Pound Portable PC}}</ref>

When the IBM PC was introduced in 1981, it was originally designated as the IBM 5150, putting it in the "5100" series, though its architecture was unrelated to the IBM 5100's.<ref>{{cite news |newspaper=[[The New York Times]]|url=https://www.nytimes.com/2011/08/01/arts/the-clunky-pc-that-started-it-all.html|title=The Clunky PC That Started It All|author=Alice Rawsthorn |date=July 31, 2011}}</ref> The 5100 was IBM's second transportable computer. Previously, a truck-based [[IBM 1401]] was configured in 1960 for military use and referred to as a ''mobile'' computer.<ref>{{cite web|title=The IBM 1401|url=http://www.columbia.edu/cu/computinghistory/1401.html|access-date=July 23, 2021|publisher=Columbia University Computing History}}</ref>

The IBM 5100 was withdrawn in March 1982, by which time IBM had announced its larger cousins, the [[IBM 5110]] (January 1978) and the [[IBM 5120]] (February 1980).

==SCAMP, the prototype==
[[File:IBM SCAMP at Smithsonian National Museum of American History.jpg|thumb|right|SCAMP prototype]]
In 1973, [[William C. Lowe|Bill Lowe]] was instrumental in fostering an engineering prototype called SCAMP (Special Computer APL Machine Portable) created by Dr. Paul Friedl and a team at the IBM Los Gatos Scientific Center.<ref name="friedl198311"/><ref>{{cite web|url= http://www.si.edu/object/nmah_334628 |title= IBM SCAMP, National Museum of American History | publisher= Smithsonian Institution |date= |access-date= 2023-02-15}}</ref> SCAMP has been dubbed in ''PC Magazine'' as "the world's first personal computer".<ref name="friedl198311" />

The IBM Los Gatos engineering prototype and a design model by IBM Industrial designer Tom Hardy, were utilized internally by Lowe in his early efforts to demonstrate the viability of creating a single-user computer.<ref name=delete>Atkinson, P, (2013) [http://www.paul-atkinson-design.com/#!design-history-of-computers ''DELETE: A Design History of Computer Vapourware''] {{Webarchive|url=https://web.archive.org/web/20140301055854/http://www.paul-atkinson-design.com/#!design-history-of-computers |date=March 1, 2014 }}, London: [[Bloomsbury Publishing]].</ref>

SCAMP emulated an [[IBM 1130]] minicomputer in order to run APL\1130.<ref>{{cite web|last=Freeman |first=Shanna |url=https://computer.howstuffworks.com/first-portable-computer.htm |website=howstuffworks.com |title=What was the first portable computer? |date=2012-09-19 |access-date=2024-11-28}}</ref> In 1973, [[APL (programming language)|APL]] was generally available only on mainframe computers, and most desktop sized microcomputers such as the [[Wang 2200]] or [[HP 9800 series|HP 9800]] offered only [[BASIC]].

Because SCAMP was the first to emulate APL\1130 performance on a portable, single user computer, ''PC Magazine'' in 1983 designated SCAMP a "revolutionary concept" and "the world's first personal computer".<ref name="friedl198311" />

==Description==
The IBM 5100 is based on a 16-[[bit]] [[central processing unit|processor]] module called [[IBM PALM processor|PALM]] ('''P'''rogram '''A'''ll '''L'''ogic in '''M'''icrocode).<ref>{{cite journal |title=A Microprocessor-based portable computer: The IBM 5100 |journal=[[Proceedings of the IEEE]] |volume=64 |issue=6 |pages=994–999 |date=June 1976 |doi=10.1109/PROC.1976.10253 |last1=Roberson |first1=D.A. |s2cid=38243836 }}</ref>   The IBM 5100 Maintenance Information Manual also referred to the PALM module as the ''controller''.  The PALM could directly address {{val|64|ul=KB}} of memory.  Some configurations of the IBM 5100 had Executable ROS ([[read-only memory|ROM]]) and [[random-access memory|RAM]] memory totalling more than {{val|64|u=KB}}, so a simple [[bank switching]] scheme was used. The actual APL and BASIC interpreters were stored in a separate ''Language ROS'' address space which the PALM treats as a peripheral device. There were twelve models available: with BASIC, APL, or both. Memory could be {{val|16|ul=KB}}, {{val|32|u=KB}}, {{val|48|u=KB}} or {{val|64|u=KB}} of main
storage.<ref name=IBM5100.MoData75/> The 5100 sold for between {{US$|long=no|8975}} and {{US$|long=no|19975}} (between ${{formatnum:{{#expr:{{Inflation|US|8975|1975}} round-3}}}} and ${{formatnum:{{#expr:{{Inflation|US|19975|1975}} round-3}}}} in today's dollars).{{r|byte197512}}

Often described as being "approximately fifty pounds",<ref>{{cite web|url=https://www.ibm.com/ibm/history/exhibits/pc/pc_2.html|title=IBM Archives: IBM 5100 Portable Computer|website=[[IBM]] |date=January 23, 2003 }}</ref> its weight was closer to 55 pounds (25&nbsp;kg). In December 1975 ''[[BYTE]]'' stated "Welcome, IBM, to personal computing". Describing the 5100 as "a 50-lb package of interactive personal computing," the magazine said that with the company's announcement "personal computing gains an entry from the industry's production and service giant," albeit "at a premium price".<ref name="byte197512">{{cite magazine |magazine=[[Byte (magazine)|Byte]]|url=https://archive.org/stream/byte-magazine-1975-12/1975_12_BYTE_00-04_Assembling_an_Altair#page/n91/mode/2up|title=Welcome, IBM, to personal computing|date=December 1975 |access-date=March 19, 2016 |page=90}}</ref>

A single integrated unit provided the keyboard, five-inch [[CRT display]], [[tape drive]], [[IBM PALM processor|processor]], several hundred KB of [[read-only memory]] containing [[system software]], and up to {{val|64|ul=KB}} of RAM.<ref name="friedl198311">{{cite magazine|magazine=[[PC Magazine]]|url=https://books.google.com/books?id=q8fwTt09_MEC&pg=RA1-PA190|title=SCAMP: The Missing Link In The PC's Past?|volume=2|issue=6|date=November 1983 |access-date=January 8, 2015|author=Friedl, Paul J. |pages=190–197}}</ref> It was the size of a small suitcase, weighed about {{val|55|ul=lb}} ({{val|25|ul=kg}}), and could be transported in an optional carrying case, hence the "portable" designation.

In 1975, it was an amazing technical accomplishment to package a complete computer with a large amount of ROM and RAM, CRT display, and a tape drive into a machine that small.  Earlier desktop computers of approximately the same size, such as the [[HP 9830]], did not include a CRT nor nearly as much memory. The 5100 has an internal CRT (five-inch diagonal) and displays 16 lines of 64 characters. IBM provided an option switch to allow the user to display all 64 characters of each line, or only the left or right 32 characters (interspersed with spaces). Also there was a switch to display the first 512 bytes of main memory in hexadecimal for diagnostic purposes.

Two solutions existed for obtaining hardcopy output: printers such as the [[IBM 5103]], and attaching a typewriter via
an interface. The ''TYCOM 5100'' (from a company named ''Tycom Systems Corporation'') enabled controlling an [[IBM Selectric]] typewriter, printing at 15.5 CPS.<ref>{{cite magazine|url=http://www.bitsavers.org/magazines/Datamation/197605.pdf|department=Hardware|title=IBM 5100 peripheral|magazine=[[Datamation]]|volume=22|issue=5|page=212|quote=transferred at a maximum of 15.5 characters per second.|date=May 1976}}</ref>

Mass storage was provided by removable [[quarter-inch cartridge]] (QIC) [[magnetic tape]] drives that use standard [[DC300]] cartridges to store {{val|204|u=KB}}. One drive was installed in the machine and a second (Model 5106) could be added in an attached box.  The data format included several types and were written in 512 byte records. The introduction of a floppy option was not until the ''IBM 5110''.<ref>{{cite web|url=http://computermuseum.informatik.uni-stuttgart.de/dev_en/ibm_5110/index.html
|title=IBM 5110}}</ref>

At the same time IBM announced the IBM 5100, it also announced the IBM 5100 Communications Adapter, which allowed the 5100 to transmit data to and receive data from a remote system. It made the 5100 appear the same as an [[IBM 2741]] Communications [[Computer terminal|Terminal]] and was designed to be able to communicate with IBM 2741 compatible machines in start-stop mode using the ''EBCD'' ('''E'''xtended '''B'''inary '''C'''oded '''D'''ecimal) notation,<ref>{{cite book |url=http://www.bitsavers.org/pdf/ibm/5100/SA21-9215-0_IBM_5100_Communications_Reference_Manual_Sep1975.pdf |title=IBM 5100 Communications Reference Manual |edition=First |date=September 1975 |publisher=IBM |id=SA21-9215-0}}</ref> referred to as PTTC/EBCD in IBM 2741 documentation.<ref>{{cite book |url=http://www.bitsavers.org/pdf/ibm/2741/A27-3002-0_2741_Communication_Terminal_OEM_Information.pdf |title=2740/2741 Communication Terminal Original Equipment Manufacturer's Information |edition=First |pages=11–14 |publisher=IBM |id=A27-3002-0 |series=IBM Systems Reference Library}}</ref>  EBCD was similar to the more common IBM [[EBCDIC]] code, but not identical. A feature that does not appear in any advertisement for this computer is an optional Serial I/O Adapter.  In order to access the port extensions, they needed to be loaded from tape for the APL and BASIC programming languages.<ref>{{cite book |url=http://www.bitsavers.org/pdf/ibm/5100/SA21-9239-1_IBM_5100_Serial_IO_Adapter_Feature_Users_Manual_Jan1977.pdf |title=IBM 5100 Serial I/O Adapter User's Manual |edition=Second |date=January 1977 |publisher=IBM |id=SA21-9239-1}}</ref>   Unlike the Communications Adapter which could only be used to connect devices that supported the IBM 2741, this feature allowed users to connect and code for any device that used a standard serial I/O port, including devices not made by IBM.<ref>{{Cite book|title=IBM 5100 Communications/Serial I/O Maintenance Information Manual|page=1{{hyp}}1|url=http://www.bitsavers.org/pdf/ibm/5100/SY31-0429-2_IBM_5100_Communications_Serial_IO_Maintenance_Information_Manual_Oct1976.pdf|access-date=December 24, 2023|publisher=IBM|id=SY31-0429-2}}</ref>

One periodical described "an interesting standard feature"; that a 5100 could be connected to a television.<ref name=IBM5100.MoData75/> An external video monitor receiver could be connected to the IBM 5100 via a [[BNC connector]] on the back panel. While the 5100 had a front panel switch to select between ''white on black'' or ''black on white'' for the internal display, this switch did not affect the external monitor, which only offered white characters on a black background. The vertical scan rate was fixed at {{val|60|ul=Hz}}.

==Research Device Coupler==
In Volume 16, Number 1, Page 41 (1977) of the IBM Systems Journal the article "The IBM 5100 and the Research Device Coupler — A personal laboratory automation system" read: "A small laboratory automation system has been developed by using the IBM 5100 Portable Computer in conjunction with the Research Device Coupler. This compact system provides a dedicated, high-level-language computer and a versatile [[data acquisition]] and control interface for experiments in which data rates do not exceed 9600 [[baud]]. Two experiments exemplify the use of the system. The Research Device Coupler described in this paper is a prototype of the IBM 7406 Device Coupler."

==Programming languages==
The 5100 was available with [[APL programming language|APL]], [[BASIC programming language|BASIC]], or both programming languages.{{r|byte197512}} At the time of introduction, APL was generally available only on mainframe computers, and most desktop sized computers such as the [[Wang 2200]] or [[HP 9830]] offered only BASIC. As a desktop computer offering APL, the 5100 competed with, and indeed may have been inspired by, the earlier [[MCM/70]].<ref name="Stachniak2011">{{cite book
    |author=Zbigniew Stachniak|title=Inventing the PC: The MCM/70 Story|url=https://books.google.com/books?id=cyWOA2FED7EC&pg=PA140|year=2011|publisher=McGill-Queen's Press - MQUP|isbn=978-0-7735-8146-3|pages=140–}}</ref>

Machines that supported both languages provided a toggle switch on the front panel to select the language. On the 5100's front panel, it was the third toggle from the left: up for APL, down for BASIC.<ref name=IBM5100.MoData75>{{cite magazine |magazine=[[Modern Data (magazine)|Modern Data]]
    |pages=50–55 |title=The IBM 5100 Portable Computer |date=October 1975}}</ref>

When the engineers at IBM asked one beta tester, Donald Polonis, for his analysis, he commented that if folks had to learn APL to use it, the IBM 5100 would not make it as a personal computer. He tried to impress the fact that a personal computer had to be easy to use to be accepted.<ref>{{cite book
   |url=https://books.google.com/books?id=lB4PAwAAQBAJ&pg=PA39
   |title=Games vs. Hardware. The History of PC video games: The 80s
   |quote=When the engineers at IBM asked one beta tester, Donald Polonis ...
   |author=Bogdan Ion Purcaru |year=2014}}</ref> Presumably, the special APL character set and APL keyboard were the primary obstacles to newcomers learning APL easily.  APL had powerful features for manipulating data as [[array data structure|vectors]] and [[matrix (mathematics)|matrices]], while the competing [[HP 9830]] had to offer language extensions on an add-on ROM for matrix operations.

Although not meant for regular users, the maintenance manual described a keyboard sequence to switch the 5100 into a maintenance mode. In this mode it was possible to read and write directly in RAM memory, video memory, CPU registers, interrupt vectors, clock counter, etc., using hexadecimal codes equivalent to assembly language. This allowed writing sophisticated programs directly into RAM. As this mode was a single-user system effectively running without an operating system, a determined user could manage the memory space and write stable multi-tasking programs using interrupts.

==Emulator in microcode==
{{main|IBM PALM processor}}
The 5100 was based on IBM's innovative concept that, using an [[emulator]] written in [[microcode]], a small and relatively cheap computer could run programs already written for much larger, and much more expensive, existing computers, without the time and expense of writing and debugging new programs.<ref name=PALM.APL1130Board>salvaging a huge IBM 1130 APL program {{cite magazine
   |magazine=[[PC Magazine]]
   |url=https://books.google.com/books?id=q8fwTt09_MEC&pg=RA5-PA9-IA1
   |title=What is a Personal Computer? |date=November 1983}}</ref>

Two such programs were included:  a slightly modified version of APLSV, IBM's APL interpreter for its [[System/370]] mainframes, and the BASIC interpreter used on IBM's [[System/3]] minicomputer.  Consequently, the 5100's microcode was written to emulate most of the functionality of both a System/370 and a System/3.

IBM later used the same approach for its 1983 introduction of the [[XT/370]] model of the [[IBM PC]], which was a standard [[IBM Personal Computer XT|IBM PC XT]] with the addition of a System/370 emulator card.

==Timeline==
{{Timeline of the IBM Personal Computer}}

== In popular culture ==
The IBM 5100 was repeatedly referenced in the [[John Titor#Titor's posts|John Titor internet hoax]] of the early 2000's. The computer also appears in the 2011 anime and visual novel series ''[[Steins;Gate]]'' as a plot device where it is called the "IBN 5100".<ref>{{Cite web|date=2021-06-01|title=Steins;Gate - The 10th Anniversary|url=https://dashgamer.com/steinsgate-the-10th-anniversary/|access-date=2021-10-07|website=DashGamer.com|language=en-US}}</ref>

==References==
{{Reflist}}

==Further reading==
* {{cite book |date=July 1977 |title=IBM 5100 BASIC Reference Manual |url=http://bitsavers.org/pdf/ibm/5100/SA21-9217-3_IBM_5100_BASIC_Reference_Manual_Jul1977.pdf |publisher=International Business Machines Corporation |edition=4th |archive-url=https://web.archive.org/web/20200727022545/http://bitsavers.org/pdf/ibm/5100/SA21-9217-3_IBM_5100_BASIC_Reference_Manual_Jul1977.pdf |archive-date=July 27, 2020 |url-status=live |archive-format=pdf}}

==External links==
{{Commons category}}
* [http://www.brouhaha.com/~eric/retrocomputing/ibm/5100/ IBM 5100 Portable Computer]
* [http://oldcomputers.net/ibm5100.html IBM 5100] | oldcomputers.net
* [https://www.oldcomputermuseum.com/ibm_5100.html IBM 5100] | oldcomputermuseum.com

{{Authority control|state=collapsed}}

{{IBM personal computers|state=collapsed}}

[[Category:Computer-related introductions in 1975]]
[[Category:IBM personal computers|5100]]
[[Category:Portable computers]]
[[Category:16-bit computers]]