Editing Booting (section)

==== First commercial computers ====
The first programmable computers for commercial sale, such as the [[UNIVAC I]] and the [[IBM 701]]<ref>{{Cite journal |date=1953 |title=The System Design of the IBM Type 701 Computer |url=http://bitsavers.org/pdf/ibm/701/Buchholz_IBM_701_System_Design_Oct53.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/ibm/701/Buchholz_IBM_701_System_Design_Oct53.pdf |archive-date=2022-10-09 |url-status=live |author-last=Buchholz |author-first=Werner |author-link=Werner Buchholz |journal=Proceedings of the I.R.E. |volume=41 |issue=10 |page=1273}}</ref> included features to make their operation simpler. They typically included instructions that performed a complete input or output operation. The same hardware logic could be used to load the contents of a [[punch card]] (the most typical ones) or other input media, such as a [[magnetic drum]] or [[magnetic tape]], that contained a bootstrap program by pressing a single button. This booting concept was called a variety of names for [[IBM]] computers of the 1950s and early 1960s, but IBM used the term "Initial Program Load" with the [[IBM 7030 Stretch]]<ref name="stretch-ipl">{{cite book |title=Reference Manual 7030 Data Processing System |section=IBM 7619 Exchange |publisher=IBM |date=August 1961 |url=http://bitsavers.org/pdf/ibm/7030/22-6530-2_7030RefMan.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/ibm/7030/22-6530-2_7030RefMan.pdf |archive-date=2022-10-09 |url-status=live |id=A22-6530-2 |pages=125–127}}</ref> and later used it for their mainframe lines, starting with the [[System/360]] in 1964.

[[File:IBM1130CopyCard.agr.jpg|thumb|Initial program load punched card for the [[IBM 1130]] (1965)]]

The [[IBM 701]] computer (1952–1956) had a "Load" button that initiated reading of the first [[36-bit]] [[word (computer architecture)|word]] into [[computer memory|main memory]] from a punched card in a [[punched card reader|card reader]], a magnetic tape in a [[tape drive]], or a magnetic drum unit, depending on the position of the Load Selector switch. The left 18-bit half-word was then executed as an instruction, which usually read additional words into memory.<ref>{{cite book |title=Principles of Operation Type 701 And Associated Equipment |url=http://bitsavers.org/pdf/ibm/701/24-6042-1_701_PrincOps.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/ibm/701/24-6042-1_701_PrincOps.pdf |archive-date=2022-10-09 |url-status=live |publisher=IBM |date=1953 |page=26 |access-date=2012-11-09}}</ref><ref>{{cite book |title=From Gutenberg to the Internet |author=Jeremy M. Norman |date=2005 |page=436 |publisher=Norman |isbn=0-930405-87-0}}</ref> The loaded boot program was then executed, which, in turn, loaded a larger program from that medium into memory without further help from the human operator. The [[IBM 704]],<ref>{{cite book|url=http://bitsavers.org/pdf/ibm/704/24-6661-2_704_Manual_1955.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/ibm/704/24-6661-2_704_Manual_1955.pdf |archive-date=2022-10-09 |url-status=live|title=704 Electronic Data-Processing Machine Manual of Operation|pages=14–15|publisher=[[IBM]]}}</ref> [[IBM 7090]],<ref>{{cite book|url=http://bitsavers.org/pdf/ibm/7090/A22-6535_7090_operGde_Jan62.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/ibm/7090/A22-6535_7090_operGde_Jan62.pdf |archive-date=2022-10-09 |url-status=live|title=Operator's Guide for IBM 7090 Data Processing System|page=34|publisher=[[IBM]]}}</ref> and [[IBM 7094]]<ref>{{cite book|url=http://bitsavers.org/pdf/ibm/7094/GA22-6703-4_7094princOps.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/ibm/7094/GA22-6703-4_7094princOps.pdf |archive-date=2022-10-09 |url-status=live|title=IBM 7094 Principles of Operation|page=146|publisher=[[IBM]]}}</ref> had similar mechanisms, but with different load buttons for different devices.  The term "boot" has been used in this sense since at least 1958.<ref>{{cite book |title=Oxford English Dictionary |date=1939 |url=https://archive.org/details/in.ernet.dli.2015.228324 |publisher=[[Oxford University]]}}</ref>

[[File:IBM System3 model 10.jpg|thumb|IBM System/3 console from the 1970s. Program load selector switch is lower left; Program load switch is lower right.]]
Other IBM computers of that era had similar features. For example, the [[IBM 1401]] system (c. 1958) used a card reader to load a program from a punched card. The 80 characters stored in the punched card were read into memory locations 001 to 080, then the computer would branch to memory location 001 to read its first stored instruction. This instruction was always the same: move the information in these first 80 memory locations to an assembly area where the information in punched cards 2, 3, 4, and so on, could be combined to form the stored program. Once this information was moved to the assembly area, the machine would branch to an instruction in location 080 (read a card) and the next card would be read and its information processed.

Another example was the [[IBM 650]] (1953), a decimal machine, which had a group of ten 10-position switches on its operator panel which were addressable as a memory word (address 8000) and could be executed as an instruction. Thus setting the switches to 7004000400 and pressing the appropriate button would read the first card in the card reader into memory (op code 70), starting at address 400 and then jump to 400 to begin executing the program on that card.<ref>{{cite book |url=http://www.bitsavers.org/pdf/ibm/650/22-6060-2_650_OperMan.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.bitsavers.org/pdf/ibm/650/22-6060-2_650_OperMan.pdf |archive-date=2022-10-09 |url-status=live |title=650 magnetic drum data-processing machine manual of operation |publisher=IBM |date=1955 |pages=49, 53–54}}</ref>  The [[IBM 7040|IBM 7040 and 7044]] have a similar mechanism, in which the Load button causes the instruction set up in the entry keys on the front panel is executed, and the channel that instruction sets up is given a command to transfer data to memory starting at address 00100; when that transfer finishes, the CPU jumps to address 00101.<ref>{{cite book|url=http://bitsavers.org/pdf/ibm/7040/A22-6741-1_Operators_Guide_for_IBM_7040-7044_Systems.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/ibm/7040/A22-6741-1_Operators_Guide_for_IBM_7040-7044_Systems.pdf |archive-date=2022-10-09 |url-status=live|title=Operator's Guide for IBM 7040-7044 Systems|page=10|id=A22-6741-1|publisher=[[IBM]]}}</ref>

IBM's competitors also offered single button program load.
* The [[CDC 6600]] (c. 1964) had a ''dead start'' panel with 144 toggle switches; the dead start switch entered 12 12-bit words from the toggle switches to the memory of [[CDC 6000 series#Peripheral processors|''peripheral processor'']] (''PP'') 0 and initiated the load sequence by causing PP 0 to execute the code loaded into memory.<ref>{{cite book|url=http://bitsavers.org/pdf/cdc/cyber/cyber_70/60045000_6600_Computer_System_RefMan_Aug63.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/cdc/cyber/cyber_70/60045000_6600_Computer_System_RefMan_Aug63.pdf |archive-date=2022-10-09 |url-status=live|title=CONTROL DATA 6600 Computer System Reference Manual|page=53|edition=Second|date=August 1963|publisher=[[Control Data Corporation]]}}</ref> PP 0 loaded the necessary code into its own memory and then initialized the other PPs.
* The [[GE-600 series|GE 645]] (c. 1965) had a "SYSTEM BOOTLOAD" button that, when pressed, caused one of the I/O controllers to load a 64-word program into memory from a diode [[read-only memory]] and deliver an interrupt to cause that program to start running.<ref>{{cite book |url=http://bitsavers.org/pdf/ge/GE-645/LSB0468_GE-645_System_Manual_Jan1968.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/ge/GE-645/LSB0468_GE-645_System_Manual_Jan1968.pdf |archive-date=2022-10-09 |url-status=live |title=GE-645 System Manual |date=January 1968 |publisher=[[General Electric]] |access-date=October 30, 2019}}</ref>
* The first model of the [[PDP-10]] had a "READ IN" button that, when pressed, reset the processor and started an I/O operation on a device specified by switches on the control panel, reading in a 36-bit word giving a target address and count for subsequent word reads; when the read completed, the processor started executing the code read in by jumping to the last word read in.<ref>{{cite book |title=PDP-10 System Reference Manual, Part 1 |url=http://bitsavers.org/pdf/dec/pdp10/1970_PDP-10_Ref/1970PDP10Ref_Part1.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/dec/pdp10/1970_PDP-10_Ref/1970PDP10Ref_Part1.pdf |archive-date=2022-10-09 |url-status=live |pages=2–72 |publisher=[[Digital Equipment Corporation]] |date=1969 |access-date=2012-11-09}}</ref>

A noteworthy variation of this is found on the [[Burroughs Corporation|Burroughs]] [[B1700]] where there is neither a [[boot ROM]] nor a hardwired IPL operation. Instead, after the system is reset it reads and executes microinstructions sequentially from a cassette tape drive mounted on the front panel; this sets up a boot loader in RAM which is then executed.<ref name="fff">{{cite book|url=http://bitsavers.org/pdf/burroughs/B1700/1057155_B1700SysRefMan11-73.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://bitsavers.org/pdf/burroughs/B1700/1057155_B1700SysRefMan11-73.pdf |archive-date=2022-10-09 |url-status=live|title=Burroughs B 1700 Systems Reference Manual|page=1{{hyp}}14|date=November 1973|publisher=[[Burroughs Corporation]]}}</ref> However, since this makes few assumptions about the system it can equally well be used to load diagnostic (Maintenance Test Routine) tapes which display an intelligible code on the [[front panel]] even in cases of gross CPU failure.<ref name="fff" />