View source for PDP-11/44

{{Infobox Machine
| name = PDP-11/44
| image=Pdp11 44.jpg 
| caption=PDP-11/44 from a sales brochure.
| manufacturer = [[Digital Equipment Corporation]]
| architecture = [[PDP-11]]
}}

[[Image:PDP11-44-geerol.jpg|150px|thumb|right|A PDP-11/44 setup]]

The '''PDP-11/44''' was a high performance [[UNIBUS]] [[PDP-11]] system; in some senses a lower-cost successor to the [[PDP-11/70]], although without the very high [[main memory]] bandwidth and I/O bandwidth to [[mass storage]] of the -11/70, as it lacked the latter's Main Memory Bus and integrated [[MASSBUS]], relying instead on the UNIBUS, and [[Extended UNIBUS|EUB]]. Its [[Central Processing Unit|CPU]], the [[KD11-Z CPU|KD11-Z]], was the last PDP-11 CPU to be made out of discrete [[integrated circuit|chips]], and not a [[microprocessor]].

The -11/44 used the EUB for its [[bus]] to main memory, allowing it to have up to 4 mega-[[byte]]s of main memory. All devices were attached to a semi-separate UNIBUS (it and the EUB shared data lines, but not [[address]] lines); [[Direct Memory Access|DMA]] devices could gain access to the memory via a [[UNIBUS map]] which connected the two, and mapped UNIBUS addresses to main memory addresses.

Full [[PDP-11 Memory Management]] and a [[cache]] (the [[KK11-B Cache Memory|KK11-B]]) were standard on all -11/44's. It also supported the optional [[FP11-F Floating-Point Processor|FP11-F]] [[floating point]] (full [[FP11 floating point]]), and/or the [[KE44-A Commercial Instruction Set Processor]] (the [[PDP-11 Commercial Instruction Set]]).

The -11/44 initially shipped with [[MS11-M MOS memory|MS11-M]]; the [[MS11-P MOS memory|MS11-P]] became available later, and was also useable in the -11/44.

Its main [[mounting box]] was the new [[BA11-A mounting box]].

== xs4all.nl ==

Quoting [http://www.xs4all.nl/~geerol/en/GAL/index.html http://www.xs4all.nl/~geerol/en/GAL/index.html]
<i>
(1979) The PDP 11/44 (hostname "gigant") is a low-cost successor of the PDP 11/70. The 11/70, brought to the market in 1975, was the first "large" PDP. Large means a 22 bit address space and a memory limit of 4MB. Do keep in mind that user programs are still limited to 16 bit addressing and hence restricted to a limit of just 2x 64KB, when using separated I&D.

The cost of a new 11/44 has been about half of the listprice of an 11/70. The PDP 11/44 had no Massbus like the /70 has, so it was not possible to use diskdrives with a transfer rate too high.</i>

== hampage.hu ==
Quoting:
<i>
1979. A middle-class -11. It had the 22-bit UNIBUS map and MMU as standard (up to 2 Mwords on a separate CPU-memory interconnect, called the PAX Memory Bus). The CPU consists of 5 boards, plus one for the FPP (FP11-F, optional), and two CIS (KE44-A, optional). Features: 8 KByte cache, ODT, 2 SLU's (Serial Line Units: console + TU58 console media), RTC (Real-Time Clock), kernel/supervisor/user modes.

The machine also had an almost-FEP (front-end processor) console, based on the Intel i8088, running from PROM. There was no QBUS equivalent.

Trivia: This was the last non-[[microprocessor]]-based PDP-11.</i>

==External links==

* [http://bitsavers.org/pdf/dec/pdp11/1144/ PDP-11/44] - Bitsavers
** [http://bitsavers.org/pdf/dec/pdp11/1144/1144_UsersGuide.pdf PDP-11/44 System User's Guide] (EK-11044-UG-003)
** [http://bitsavers.org/pdf/dec/pdp11/1144/1144_SystemTechMan.pdf PDP-11/44 System Technical Manual] (EK-KD11Z-TM-001)
** [http://bitsavers.org/pdf/dec/pdp11/1144/MP00897_11X44sys_Dec79.pdf 11X44 Field Maintenance Print Set] (MP00897)

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[[Category: UNIBUS PDP-11s]]
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