Editing Digital Equipment Corporation (section)

=== PDP-1 family (1960) ===
{{Main|PDP-1}}
[[File:Steve Russell and PDP-1 - Vintage Computer Fair 2006.jpg|thumb|right|A [[PDP-1]] system, with [[Steve Russell (computer scientist)|Steve Russell]], developer of [[Spacewar!]] at the console. This is a canonical example of the PDP-1, with the console typewriter on the left, CPU and main control panel in the center, the Type 30 display on the right.]]

With the company established and a successful product on the market, DEC turned its attention to the computer market once again as part of its planned "Phase II".<ref name=proposal/> In August 1959, Ben Gurley started design of the company's first computer, the [[PDP-1]]. In keeping with Doriot's instructions, the name was an [[initialism]] for "[[Programmable Data Processor]]", leaving off the term "computer". As Gurley put it, "We aren't building computers, we're building 'Programmable Data Processors'." The prototype was first shown publicly at the Joint Computer Conference in Boston in December 1959.<ref>[http://www.computerhistory.org/collections/accession/102634161 Eastern Joint Computer Conference and Exhibition], official program of 1959 meeting in Boston</ref> The first PDP-1 was delivered to [[Bolt, Beranek and Newman]] in November 1960,<ref>{{cite web |date=January 30, 1998 |title=1960 Timeline |url=https://research.microsoft.com/en-us/um/people/gbell/Digital/timeline/1960.htm |access-date=September 6, 2022 |work=DIGITAL Computing Timeline}}</ref> and formally accepted the next April.<ref>''Computers and Automation'', April 1961, pg. 8B</ref> The PDP-1 sold in basic form for $120,000 ({{Inflation|US|120000 |1961|r=0|fmt=eq}}).<ref>[http://www.bls.gov/data/inflation_calculator.htm "Bureau of Labor Statistics Inflation Calculator, 1961–2025"]</ref> By the time production ended in 1969, 53 PDP-1s had been delivered.<ref name=present3/><ref>"History of Computing", Lexikon Services, {{ISBN|0-944601-78-2}}</ref>

The PDP-1 was supplied standard with 4096 words of [[core memory]], [[18-bit computing|18-bit]]s per word, and ran at a basic speed of 100,000 operations per second. It was constructed using many System Building Blocks that were packaged into several [[19-inch rack]]s. The racks were themselves packaged into a single large mainframe case, with a hexagonal control panel containing switches and lights mounted to lie at table-top height at one end of the mainframe. Above the control panel was the system's standard [[input/output]] solution, a [[punched tape]] reader and writer. Most systems were purchased with two [[peripherals]], the Type 30 [[vector graphics]] display, and a [[Soroban Engineering]] modified [[IBM Electric typewriter|IBM Model B Electric typewriter]] that was used as a [[printer (computing)|printer]]. The Soroban system was notoriously unreliable, and often replaced with a modified [[Friden Flexowriter]], which also contained its own punched tape system. A variety of more-expensive add-ons followed, including [[magnetic tape]] systems, [[punched card]] readers and punches, and faster punched tape and printer systems.

When DEC introduced the PDP-1, they also mentioned larger machines at 24, 30 and 36 bits, based on the same design.<ref>''Datamation'', Volume 5 Number 6 (November/December), pg. 24</ref> During construction of the prototype PDP-1, some design work was carried out on a 24-bit PDP-2, and the 36-bit PDP-3. Although the PDP-2 never proceeded beyond the initial design, the PDP-3 found some interest and was designed in full.<ref>{{cite book|url=https://www.gutenberg.org/ebooks/29461|title=Preliminary Specifications: Programmed Data Processor Model Three (PDP-3)|publisher=DEC|date=October 1960}}</ref> Only one PDP-3 appears to have been built, in 1960, by the CIA's Scientific Engineering Institute (SEI) in [[Waltham, Massachusetts]]. According to the limited information available, they used it to process radar cross section data for the [[Lockheed A-12]] [[reconnaissance aircraft]]. [[Gordon Bell]] remembered that it was being used in [[Oregon]] some time later, but could not recall who was using it.<ref>{{cite web|url=http://www.decconnection.org/announcements.htm|title=Announcements from The DEC Connection|at=Anyone seen a PDP-3 lately?|website=The DEC Connection|date=January 14, 2007|access-date=March 8, 2010|archive-date=February 25, 2019|archive-url=https://web.archive.org/web/20190225233751/http://www.decconnection.org/announcements.htm|url-status=dead}}</ref>

In November 1962, DEC introduced the $65,000 [[PDP-4]]. The PDP-4 was similar to the PDP-1 and used a similar instruction set, but used slower memory and different packaging to lower the price. Like the PDP-1, about 54 PDP-4s were eventually sold, most to a customer base similar to the original PDP-1.<ref>{{cite web |date=January 30, 1998 |title=PDP-4 |url=http://research.microsoft.com/en-us/um/people/gbell/digital/timeline/1962-1.htm |access-date=September 6, 2022 |work=DIGITAL Computing Timeline}}</ref>

In 1964, DEC introduced its new [[Flip-Chip module]] design, and used it to re-implement the PDP-4 as the [[PDP-7]]. The PDP-7 was introduced in December 1964, and about 120 were eventually produced.<ref>{{cite web |date=January 30, 1998 |title=PDP-7 |url=http://research.microsoft.com/en-us/um/people/gbell/digital/timeline/1964-3.htm |access-date=January 9, 2014 |work=DIGITAL Computing Timeline}}</ref> An upgrade to the Flip Chip led to the R series, which in turn led to the PDP-7A in 1965.<ref>{{cite web |date=January 30, 1998 |title=PDP-7A |url=http://research.microsoft.com/en-us/um/people/gbell/digital/timeline/1965-1.htm |access-date=September 6, 2022 |work=DIGITAL Computing Timeline}}</ref> The PDP-7 is most famous as the machine for which the [[Unix]] operating system was originally written.<ref>{{cite web|first=Eric Steven|last=Raymond|author-link=Eric S. Raymond|url=http://www.catb.org/~esr/writings/taoup/html/ch02s01.html|title=Origins and History of Unix, 1969–1995|date=September 19, 2003}}</ref> Unix ran only on DEC systems until the [[Interdata 8/32]].<ref name="fiedler198310">{{cite magazine | url=https://archive.org/stream/byte-magazine-1983-10/1983_10_BYTE_08-10_UNIX#page/n133/mode/2up | title=The Unix Tutorial / Part 3: Unix in the Microcomputer Marketplace | magazine=[[Byte (magazine)|Byte]] |volume=8 |issue=10 | date=October 1983 | access-date=January 30, 2015 | last=Fiedler |first=Ryan | page=148}}</ref>

A more dramatic upgrade to the PDP-1 series was introduced in August 1966, the [[PDP-9]].<ref>{{cite web |date=January 30, 1998 |title=PDP-9 |url=http://research.microsoft.com/en-us/um/people/gbell/digital/timeline/1966-1.htm |access-date=September 6, 2022 |work=DIGITAL Computing Timeline}}</ref> The PDP-9 was instruction-compatible with the PDP-4 and −7, but ran about twice as fast as the −7 and was intended to be used in larger deployments. At only $19,900 in 1968,<ref>DEC Advertisement, ''Chemical and Engineering News'', Volume 46 (1968), pg. 85</ref> the PDP-9 was a big seller, eventually selling 445 machines, more than all of the earlier models combined.<ref name="miller452">Miller 1997, pg. 452</ref>

Even while the PDP-9 was being introduced, its replacement was being designed, and was introduced as 1969's [[PDP-15]], which re-implemented the PDP-9 using [[integrated circuits]] in place of modules. Much faster than the PDP-9 even in basic form, the PDP-15 also included a [[floating point unit]] and a separate [[input/output]] processor for further performance gains. Over 400 PDP-15's were ordered in the first eight months of production, and production eventually amounted to 790 examples in 12 basic models.<ref name=miller452/> However, by this time other machines in DEC's lineup could fill the same niche at even lower price points, and the PDP-15 would be the last of the 18-bit series.