Editing Prime Computer (section)

==Minicomputer products==
The initial offerings by Prime were clones of Honeywell's [[Honeywell 316|DDP 316]] and 516 minicomputers. Main competitors were [[Digital Equipment Corporation]], [[Data General]] and [[Hewlett-Packard]].<ref name=NYT.JoeIBM/> {{asof|1975|06}} [[time-sharing]] was Prime's largest end-user market, and 25% of revenue was from [[OEM]]. Overseas markets provided 42% of revenue in the first quarter of 1975.<ref name="upton19750611">{{Cite magazine |last=Upton |first=Molly |date=1975-06-11 |title=Prime President Predicts '75 Orders On Target, Despite Recent Slowdown |url=https://books.google.com/books?id=79Vx176yQBEC&pg=PA35 |access-date=2024-10-23 |magazine=Computerworld |page=35}}</ref>

*1972: Prime 200<ref name=HistBRO/>
:The first Prime system was similar to the 16-bit DDP 516. It ran an operating system called DOS, also referred to as [[PRIMOS 2]] (not to be confused with [[MS-DOS]], [[PC DOS]], etc.).
*1973: Prime 100
:The Prime 100 was a stripped down version of the Prime 200 (no memory parity or floating point).
*1974: Prime 300
:The [[#Prime 300 specification|Prime 300]] had a main store of 32&nbsp;KB to 512&nbsp;KB and from 6&nbsp;MB of [[Pertec]] disk storage. It ran DOSVM operating system, also referred to as [[PRIMOS 3]], but still used earlier DOS for booting. One of the first minicomputers with microcode-supported virtual memory capability. The virtual memory was simpler than used in later systems. Addresses were 16&nbsp;bits, with each of up to 32 time-sharing (time slice) users, receiving a virtual 64&nbsp;K-word address space. It had ''S-mode'' and ''R-mode'' instructions. 
 
:An example of the Prime 300 was installed in the mathematics department of the [[Aston University|University of Aston in Birmingham]], UK and at the Medical University of Hannover, Germany.

*1976: Prime 400
:The Prime 400 ran at 0.5&nbsp;MIPS, had a main store of up to 8&nbsp;MB and 160&nbsp;MB of disc storage. The name PRIMOS was now used for the operating system, and the P400 ran [[PRIMOS 4]]. It ran a ''V-mode'' instruction set, along with the S-mode and R-mode instructions. It had a [[Memory segmentation|segmented]] virtual memory architecture, somewhat similar to [[Multics]].

*1979: Prime 450, 550, 650, 750<ref>{{cite web |url=http://www.chilton-computing.org.uk/acd/icf/mums/prime/p009.htm
|title=Prime 750 System}}</ref>—the beginning of the 50 series nomenclature<ref>although some 50-numbered machines had a 55-ending followup</ref><ref>A 9955-II followed the high-end 9955</ref>

:The Prime 550 was an upgrade in performance over the Prime 400. It ran at 0.7&nbsp;MIPS, had up 2&nbsp;MB of memory and 500&nbsp;MB of disc storage and a [[9-track tape]] unit.<ref>It didn't have to come from Prime; some tape drive vendors sold them to Prime customers{{cite web|url=http://www.comco-inc.com/9-track-solutions-c167.html |title=Tape Drives: 9 Track Tape Drives - Comco}}</ref>

:The Prime 750 was a major upgrade. It ran at 1.0&nbsp;MIPS, had 2–8&nbsp;MB of memory and 1200&nbsp;MB of disc storage and a 9-track tape unit. This was very competitive with a similarly priced [[Digital Equipment Corporation|DEC]] [[VAX-11|VAX-11/780]] and was one of the first [[32-bit]] [[superminicomputer]]s. Prime 750 systems were installed at [[Rensselaer Polytechnic Institute]] (RPI), [[Rutherford Appleton Laboratory]] (RAL), [[University of Paisley]], [[Leeds University]], [[Scripps Institution of Oceanography]] (SIO), University of Rhode Island, [[University of Manchester Institute of Science and Technology]] (UMIST), the [[CADCentre]] in Cambridge, and Southeastern University in Washington, DC, Teesside University.

PRIMENET and a [[local area network]]ing software product named RINGNET were announced.
*1980: Prime 150 and 250
*1981: Prime 850 (dual CPU machine)

Prime also marketed [[MEDUSA4|MEDUSA]] CAD software.

[[Image:Prime9950 kean.jpg|thumb|A Prime 9950 computer system with CRT console in [[Kean University]] computer room]]
*1982: Prime 2250 also known internally as "Rabbit"
*1983: Prime 9950<ref name=NYT.JoeIBM/><ref>described both by Prime and NYTimes as a "superminicomputer."</ref>
*1984: Prime 2550, 9650, 9750
*1985: Prime 9955, 9655, 2655

:The 9955 ran at 4.0&nbsp;MIPS, had 8–16&nbsp;MB of memory and 2.7&nbsp;GB of disc storage and a 9-track tape unit.
:Five Prime 9955 computers (uk.ac.salford.sysa to .syse, connected to [[JANET]]) were installed at the University of Salford (along with other systems such as the 2250, 2550, and 750); a Prime 9955 was installed at UMIST and a Prime 9655 at Nottingham University.

*1986: Prime 2350, 2450, 9755, and 9955-II
*1987: Prime 2455, 2755, 6350, and 6550
*1989: Prime 2850, 4050, 6450, and 6650
*1990: Prime 2950, 4150, and 6150

By 1987, Prime Computer had introduced an alternative line of Intel 80386-based computers, the EXL-316 series, running the [[Unix]] operating system.<ref>{{cite book |title= Authorized Reseller Price Book |publisher= Prime Computer, Inc. |date=August 1987 |url= http://www.bitsavers.org/pdf/prime/50_series/SOU-2104-002_Reseller_Price_Book_Aug87.pdf |pages= 2–17}}</ref> A "new line of Unix-based EXL-7000 computers" was announced in late 1990.<ref>{{cite magazine |magazine=[[Datamation]]
|title=Shielding Prime From Mini Downturn
|author=Tim Mead  |date=November 1990 |pages=95–96}}</ref>

The company was successful in the 1970s and 1980s, peaking in 1988 at number 334 of the [[Fortune 500]]. In 1985, the company was the sixth largest in the minicomputer sector, with estimated revenues of US $564 million <ref name=Chan05/> Much of this was based on the U.S. banking industry where the Prime Info database was widely accepted.

As of later 1989, Surrey University had the largest Prime site in Europe, having  multiple copies of virtually every 50 series  machine (mostly running Primos 20.x, but some still running 19.x).