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PDP-7

The PDP-7 was an 18-bit developed and manufactured by (DEC) as a low-cost alternative to earlier models in its series, with production running from 1964 to 1969 and approximately 120 units shipped. It featured a cycle time of 1.75 microseconds, core memory starting at 4K words (expandable to 64K), and was the first DEC machine to employ Flip-Chip modular technology for more compact and reliable construction. Priced at around $72,000 for a minimal configuration, it targeted , , and research applications in scientific, industrial, and academic settings. The PDP-7 introduced several manufacturing innovations, including the use of automatic wire-wrapping for assembly—a process programmed on earlier DEC systems—which marked a shift toward more efficient production methods and paved the way for future models like the PDP-8. A variant, the PDP-7A released in 1965, incorporated DEC's newer R-series Flip-Chip modules, enhancing performance and compactness while maintaining compatibility with existing peripherals such as Teletype terminals, drives, and displays. These advancements contributed to DEC's growing dominance in the market during the , where the PDP-7 served as a versatile platform for early computing experiments. Historically, the PDP-7 gained enduring significance for its role at , where in 1969 Ken and Dennis used it to develop the initial version of the Unix operating system and the precursors to , fundamentally influencing modern . This work began on a salvaged PDP-7 with a DEC 340 , establishing core Unix concepts like the structure with i-nodes and directories that persist today. Beyond , installations at institutions like in the early 1970s supported electrical engineering research, underscoring the machine's impact on academic computing.

Development and Release

Design Origins

The PDP-7 emerged as part of Digital Equipment Corporation's (DEC) ongoing PDP series, succeeding the PDP-4 introduced in 1962 and serving as a low-cost alternative to earlier models like the and PDP-4 while preserving substantial computational power in an 18-bit architecture. Designed to address the growing demand for affordable computing in laboratory and process control environments, it built on DEC's experience with prior systems to emphasize modularity and reliability without sacrificing performance. Key design goals centered on delivering 18-bit processing capabilities to scientific and industrial users at a reduced , with a standard configuration priced at approximately $72,000—significantly lower than many contemporaries. The system shared an instruction set with the PDP-4 and the subsequent PDP-9, ensuring software compatibility and allowing users to leverage existing PDP-4 program libraries, such as the field-proven . This compatibility was a deliberate choice to minimize development costs for customers and accelerate adoption in handling and computing applications. Among its innovations, the PDP-7 was the first DEC computer to employ Flip-Chip modular technology, utilizing silicon-based modules for compact, reliable implementation that facilitated easier assembly and maintenance. It also introduced wire-wrapping as the primary construction technique, enabling automated production wiring for improved manufacturing efficiency and serviceability over hand-soldered predecessors. These advancements supported engineering targets of a 1.75 µs memory cycle time and 4 µs add time, optimizing the system for high-speed operations in constrained budgets. Development of the PDP-7 was conceptualized in the early following the PDP-4, with active engineering commencing in April 1964 and the first prototype completed within nine months. Production units began shipping in November 1964, marking a rapid timeline that kept total design costs under $100,000 (excluding modules and staff). This efficient process reflected DEC's maturing expertise in design, positioning the PDP-7 as a bridge to more advanced systems like the PDP-9.

Announcement and Variants

The PDP-7 was introduced by (DEC) in late 1964 as a successor to the PDP-4, marking a significant step in the evolution of affordable computing systems. First production units began shipping to customers in November 1964, enabling rapid deployment in specialized applications. Marketed as a breakthrough in design, the PDP-7 emphasized an exceptional price-performance ratio, with a base price of approximately $72,000 that made high-speed accessible to institutions previously reliant on larger mainframes. This positioning attracted early adopters primarily from research laboratories and universities, where its solid-state architecture supported scientific computing and control tasks. In 1965, DEC released the PDP-7A as an upgraded variant, incorporating the newer R-series Flip-Chip s to enhance reliability and reduce overall system size through more efficient packaging in a smaller cabinet. These changes included minor performance improvements, such as optimized density, while maintaining compatibility with the original PDP-7's 18-bit and peripherals. The PDP-7A addressed feedback on physical footprint and maintenance, making it suitable for constrained laboratory environments. Overall, DEC produced a total of 120 units across the PDP-7 and PDP-7A variants from 1964 to 1969, reflecting targeted production for niche markets. By the end of 1965, 11 systems had been exported to the , underscoring early international interest in government and academic research sectors.

Hardware Design

Processor and Architecture

The PDP-7 employed an 18-bit word length and a single-address , enabling efficient execution of instructions that operated primarily on the accumulator . Its central featured a cycle time of 1.75 microseconds and an time of 3.5 microseconds, supporting a rate of approximately 285,000 per second. The design incorporated 16 basic instructions, expandable through operate, transfer (IOT), and extended arithmetic element (EAE) classes, which facilitated a range of operations from basic data manipulation to more complex arithmetic tasks. The instruction set emphasized simplicity and compatibility, with key memory reference opcodes including LAC (octal 20, load accumulator), DAC (octal 04, deposit accumulator), ADD (octal 30, add to accumulator), TAD (octal 34, two's complement add), JMP (octal 60, jump), and JMS (octal 10, jump to subroutine). Operate instructions handled logical operations, shifts, and skips, such as CLA (clear accumulator) and IAC (increment accumulator), while IOT instructions managed device interactions and EAE options supported multiplication and division. This set ensured binary portability with the PDP-4 and PDP-9, allowing software developed for those systems to run on the PDP-7 with minimal modifications. Addressing utilized a 13-bit direct mode within each memory field, accommodating up to 8,192 words per field, with memory extension options enabling a total of up to 32,768 words across multiple fields; indirect addressing (indicated by a specific bit in the address field) enabled deferred addressing and effective expansion beyond direct limits through chaining. Architecturally, the PDP-7 relied on discrete transistors for its initial implementation, utilizing modular Flip-Chip cards to organize CPU logic into compact, interchangeable units that enhanced maintainability and . The PDP-7A later transitioned to integrated circuits in its Flip-Chip modules, improving reliability and reducing power consumption while preserving the core architecture. This modular approach, combined with 1's complement arithmetic (with support for in multi-precision operations) and support for auto-indexing in designated memory locations, underscored the PDP-7's focus on high-speed, laboratory-oriented processing. The shared with the PDP-9 further promoted software reuse across DEC's 18-bit lineup.

Memory and Peripherals

The PDP-7 utilized technology, which provided non-volatile storage typical of mid-1960s minicomputers. The base configuration included 4,096 18-bit words of core memory, equivalent to approximately 9 , with a complete cycle time of 1.75 microseconds that synchronized directly with the processor's instruction execution for efficient access. This cycle time enabled a rate of up to 285,000 additions per second, emphasizing the system's focus on high-speed handling in laboratory and process control environments. Memory expansion was achieved through modular additions, such as the Type 147 Core Module, which doubled the to 8,192 words, and the Type 148 Extension paired with Type 149 modules, allowing further increments of 4,096 or 8,192 words up to a maximum of 32,768 words (approximately 73 KB). These expansions maintained the same 1.75 µs access time, supporting larger programs and datasets without performance degradation, though additional power supplies like Type 739 were required for the read/write and inhibit currents in extended configurations. The PDP-7 supported a range of standard peripherals for input, output, and auxiliary storage, integrated via its input/output control system. Core options included a Teletype Model 33 KSR typewriter keyboard for console interaction at 10 characters per second, a high-speed perforated paper tape reader (Type 444 at 300 characters per second) and punch (Type 75 at 63.3 characters per second) for program loading and data exchange, and an automatic line printer (Type 647) capable of 300 to 1,000 lines per minute across 120 columns. For mass storage, the DECtape Type 555 dual-drive system provided reliable magnetic tape handling at 80 inches per second, with each reel offering a capacity of about 3 million bits (roughly 375 KB), serving as a versatile medium for software distribution and data backup. Input/output mechanisms employed both and interfaces, with the system's I/O control accommodating up to 64 devices through dedicated selectors, collectors, and distributors. (DMA) was facilitated by the Type 173 Data Interrupt Multiplexer, enabling cycle-stealing transfers for high-speed peripherals at rates up to 570,000 words per second and supporting asynchronous operations for devices like printers alongside synchronous ones for tapes. Expansion occurred via a connector panel in the main cabinet, allowing integration of optional peripherals such as transports (Type 570 at 75 or 112.5 inches per second) or card readers (Type 421A at 200 or 800 cards per minute) without requiring extensive rewiring. Physically, the PDP-7 was housed in a self-contained three-bay DEC metal measuring 69 1/8 inches high, 61 3/4 inches wide, and 33 9/32 inches deep, adhering to standard mounting for internal components while providing space for peripherals like the Teletype on an adjacent table. The system weighed approximately 1,130 pounds (512 kg) in its basic configuration, reflecting the robust construction needed for reliability in industrial settings. Power consumption totaled around 2,200 watts from a 115-volt, Hz single-phase supply, with no special or floor reinforcement required, making it suitable for typical laboratory installations.

Software Support

Operating Systems

The primary operating system developed by (DEC) for the PDP-7 was DECSYS-7, introduced in 1966 as the company's first mass-storage-based system leveraging technology. DECSYS-7 supported for scientific computing tasks, including , , and loading of programs in and assembler languages, with go/wait modes for and execution. File management relied on units, organized into 576 blocks of 256 18-bit words each, enabling editing of system tapes, library files, and working programs through utilities like , , and CONTENTS for versioning and maintenance. This system required at least 8,192 words of core memory and two transports, facilitating efficient handling of relocatable binary and source code in a single-user environment. In 1969, at developed the initial version of what became Unix—initially dubbed "Unics"—on the PDP-7, marking it as Version 0 of the operating system. Written entirely in PDP-7 , this implementation experimented with innovative concepts, such as separating naming functions from storage allocation, and provided a hierarchical that influenced subsequent Unix designs. Unlike the more robust features of later versions, Unix Version 0 was a minimal single-user system without full multitasking capabilities, reflecting the PDP-7's hardware constraints. The source code, preserved through historical efforts, has been restored and runs on both emulated and surviving PDP-7 hardware today, demonstrating its foundational role in operating system evolution. Beyond these, the PDP-7 saw limited support for (RTOS) variants tailored to specific applications, often as custom software stacks rather than comprehensive kernels. One example is LOCOSS (Logic Of Computer Operating System for the PDP-Seven), a 1968 run-time for application programs. These provided basic support for applications, including handling inherent to the hardware, but lacked advanced task scheduling or multitasking found in later Unix versions on the PDP-11. Additionally, the PDP-7 served as a platform for , a multi-user programming system with integrated utilities that functioned in a resource-constrained .

Programming Tools

The primary low-level programming tool for the PDP-7 was the Symbolic Assembler, which enabled programmers to write code using mnemonic instruction names (such as ADD or JMP) and symbolic addresses in place of raw octal or binary values, facilitating direct hardware control over the 18-bit processor, memory, and peripherals like teleprinters and tape drives. This one-pass assembler supported relocatable code assembly, allowing modules to be positioned dynamically in memory during loading, and included pseudo-instructions for defining constants, external references, and library linkages to promote modular development. High-level languages were supported through the , introduced in 1965, which translated mathematical and procedural statements into optimized for scientific computations, including support for fixed- and , DO loops, conditional branching, and subroutine calls. The allowed embedding of inline instructions within Fortran source for performance-critical sections and generated relocatable compatible with the system's linker, while providing a of mathematical functions like SQRTF and SINF. Early development of the B language, a typeless precursor to , occurred on the PDP-7 under the initial Unix system around 1969, where it was compiled to support system programming and file handling experiments. The PDP-7's development environment centered on paper tape as the primary medium for source code input, with loaders such as the FF Loader and RIM Loader reading binary or relocatable tapes to initiate program execution from specific memory locations. Debugging relied on the DDT (Dynamic Debugging Technique) tool, an interactive symbolic debugger that permitted examination of memory contents, register values, and breakpoints using assembler-level symbols, occupying the upper 2000 words of an 8K memory configuration. Linkage editors within the assembler and loader ecosystem combined multiple relocatable modules and resolved external symbols to produce final executables, streamlining the build process for larger programs. Toolchain evolution included DECSYS-7, a DECtape-based introduced for batch-oriented workflows, which automated compilation of source into intermediate code, assembly into relocatable binaries, and loading, minimizing manual tape handling and supporting up to five sequential jobs per run on systems with at least 8K memory. This integration enhanced efficiency for repetitive development tasks, bridging standalone tools with structured processing.

Applications and Uses

Scientific and Research Roles

The PDP-7 found significant deployment in scientific laboratories for and tasks, particularly in physics research. For instance, it was utilized in studies to compute few-group flux and power profile distributions, achieving acceptable results when integrated with analog computers for simulations. In , the Laboratory of Computer Science developed the (Massachusetts General Hospital Utility Multi-Programming System) database and programming language starting in 1966 on a PDP-7, enabling early and influencing subsequent healthcare computing systems. By 1970, this implementation had matured to support DEC's distribution of implementations across PDP systems. In industrial settings, the PDP-7 supported process control applications in environments, leveraging its high-speed data handling capabilities for monitoring and . Its design emphasized reliability in , with dedicated I/O interfaces facilitating integration into production lines. Additionally, the PDP-7A variant enabled early experiments in , such as at , where it served as an interactive front-end processor for light-pen input and display refresh in engineering visualization tasks. Notable projects on the PDP-7 included Ken Thompson's 1969 port of the Space Travel simulation game at , a solar system navigation program that demonstrated file handling techniques and directly spurred the initial development of the Unix operating system on the machine. The PDP-7 also facilitated early experiments at , providing multi-user access that prefigured networked computing paradigms like those in nodes. The PDP-7's user base primarily consisted of universities and government research labs, where its 99 units offered affordable computing power outside traditional mainframe environments, enabling dedicated setups for specialized scientific workloads.

Cultural and Historical Impact

The PDP-7 played a pivotal role in the origins of Unix, serving as the primary development platform at Bell Labs from 1969 to 1970, where Ken Thompson and Dennis Ritchie implemented early versions of the operating system, including innovative file system designs that separated naming from data storage and the B programming language compiler. This work on the PDP-7 laid foundational concepts for hierarchical file systems and high-level languages, with the B compiler initially written for the machine itself before porting to the PDP-11, which enabled the full realization of Unix. The PDP-7's modest resources—8K words of core memory—forced efficient design choices that influenced Unix's portability and simplicity, bridging experimental ideas to a widely adopted system. As an early minicomputer, the PDP-7 exemplified the shift from expensive mainframes to more accessible machines, contributing to Digital Equipment Corporation's (DEC) rise by offering solid-state processing at a fraction of the cost of larger systems, priced around $72,000 for a basic configuration. This affordability spurred the minicomputer revolution, influencing DEC's subsequent successes and prompting competitors like Data General, founded by former DEC engineers in , to develop rival systems such as the that targeted similar markets. The PDP-7's use in environments like fostered early , where resource-constrained programming encouraged creative problem-solving and communal knowledge-sharing, principles that resonated in education. Its role in developing tools like the B language and initial Unix components inspired curricula emphasizing and operating system design in the late 1960s and 1970s. Among its technical milestones, the PDP-7 was DEC's first commercially produced computer using automated wire-wrapping for assembly, enabling faster and more reliable manufacturing that reduced costs and improved scalability for minicomputers. This innovation paved the way for the PDP-8's mass-market triumph in 1965, which became the best-selling computer of its era with over 50,000 units produced, solidifying the viability of small-scale computing. Additionally, a PDP-7 at supported the initial implementation of , a database-oriented language that advanced medical computing by enabling efficient handling of patient records.

Production and Sales

Manufacturing Process

The PDP-7 was primarily manufactured at Digital Equipment Corporation's (DEC) facility in , where production ramped up following the system's design completion in 1964. The first prototype was assembled by December 1964, with initial production units delivered shortly thereafter and full-scale low-volume custom builds commencing in 1965. This approach reflected DEC's strategy for niche 18-bit systems, emphasizing tailored configurations for laboratory and applications rather than mass production. Assembly techniques for the PDP-7 marked a significant advancement in DEC's , as it was the first system in the PDP series to employ automatic wire-wrapping for backplanes, a process controlled by software developed on earlier PDP models. The core logic utilized B-series Flip-Chip modules, which were inserted into wire-wrapped backplanes for interconnectivity, while subsystems in later configurations incorporated slower 2 MHz R-series modules. These modular components facilitated efficient and , transitioning from hand-built prototypes—such as the initial unit crafted by a DEC field service engineer—to more standardized production runs. Component integration centered on magnetic core memory, provided through DEC's proprietary Type 147 modules that supported expansions from 4K to 64K words, with a cycle time of 1.75 microseconds. The PDP-7A variant, introduced around 1965-1966, advanced this by incorporating early integrated circuits (ICs) alongside R-series modules, enhancing performance and reducing component count compared to the transistor-based original. The modular Flip-Chip design inherently supported quality control by enabling straightforward field upgrades and repairs, contributing to the system's reliability in demanding environments. Due to its custom-oriented production, total output was limited to approximately 120 units.

Market Performance

The PDP-7 was introduced with a base price of $72,000 in 1965 for a minimal , making it an affordable option compared to larger systems of the . This price equated to approximately $728,319 in 2025 dollars, adjusted for as of November 2025. Optional peripherals and memory expansions typically increased the by 20-50%, depending on the specific setup chosen by customers. Approximately 120 units of the PDP-7 and its PDP-7A variant were produced and sold from late to the late , meeting DEC's initial sales target amid strong demand, though a 1972 service list records 99 installations. The system sold out by 1969, reflecting robust market interest in its compact design and performance for specialized needs. Sales were distributed primarily across scientific and sectors, accounting for the majority of installations in laboratory and environments, with notable penetration into research facilities. Education, particularly universities, represented about 10% of the market, including several shipments to institutions in the UK. The PDP-7 competed effectively against higher-cost alternatives like the by offering superior value in terms of price-to-performance for mid-sized tasks. The PDP-7 received positive reception for its reliability, with some units accumulating tens of thousands of operational hours without major failures, earning praise in and experimental settings. Its commercial success contributed to DEC's rapid revenue expansion during the mid-1960s, as company sales grew from around $15 million in 1965 to nearly $39 million by 1967, helping establish the foundation for the blockbuster PDP-8 line.

Legacy and Preservation

Restored Examples

As of 2020, at least five PDP-7 systems were confirmed to survive, encompassing both original PDP-7 and PDP-7A variants acquired from various historical sites. Notable restorations include the PDP-7 at the former Living Computers Museum + Labs in Seattle, Washington, which was restored to operate Unix version 0 alongside the B compiler following hardware revival efforts from 2011 to 2019. Following the museum's permanent closure in 2020, its collection, including the PDP-7, was auctioned in 2024; the machine's current whereabouts are unknown as of 2025. The in , preserves a PDP-7 ( 5098) from 1964, donated by . In , a PDP-7A ( 115), originally delivered to the in 1966, is preserved in a private collection following partial restoration efforts, though full operational status was not achieved. Additionally, a PDP-7 in a private Australian collection is preserved intact for educational display, though restoration was not pursued due to hardware reliability issues. Restoration initiatives, exemplified by the Living Computers Museum project spanning 2011 to 2019, required procuring scarce components like memory interfaces and custom single-board computers for disk emulation, coupled with iterative debugging to resolve hardware instabilities. A primary hurdle across these efforts remains the limited availability of Flip-Chip modules essential to the PDP-7's architecture, often necessitating fabrication of substitutes. Teams frequently employed PDP-7 emulators, such as those in the suite, to validate repairs and software compatibility prior to full hardware integration. The Living Computers PDP-7 demonstrated Unix v0 functionality through boot sequences and user logins until the museum's closure.

Ongoing Efforts

Ongoing efforts to preserve the PDP-7 focus on software archiving, , and community-driven recovery projects to ensure the system's historical materials remain accessible. In 2025, the Bitsavers archive continued its documentation of PDP-7 binaries and related documentation, contributing to a collection exceeding 179,000 files by July of that year, which includes scans and digital copies of original software distributions. Emulation plays a key role in these preservation activities, with the simulator supporting PDP-7 hardware and operating systems such as DECsys, the first OS for the 18-bit product line. Additionally, open-source projects have resurrected early Unix version 0 for the PDP-7 using , based on scans of original assembly code, allowing modern researchers to execute and study this foundational software without physical hardware. Community initiatives, particularly through the Vintage Computer Federation, have advanced PDP-7 software recovery in 2025, including the imaging of full ACONIT sets for PDP-7 and PDP-9 systems to salvage lost binaries. Parallel efforts involve open-source recreations of Flip-Chip schematics, with templates enabling the design of compatible modules for DEC's modular hardware architecture. Educational programs in the incorporated the PDP-7 into exhibits to teach , such as demonstrations of its role in early operating system development. Projects like those at the former Living Computers: + Labs ran Unix version 0 on restored PDP-7 systems to illustrate the machine's place in Unix genealogy, providing hands-on learning for visitors and students until 2020. Future challenges in PDP-7 preservation include sourcing obsolete components like Flip-Chip modules and DECtapes for hardware restorations, as original parts dwindle and modern equivalents require custom fabrication. Digital archiving of magnetic tapes remains critical to combat , with ongoing recoveries emphasizing migration to stable formats to prevent in aging media.

References

  1. [1]
    The Digital Equipment Corporation PDP-7 - Columbia University
    The PDP-7, produced 1964-69, is famous for the development of UNIX and C at Bell Labs. It was also at Columbia University in the early-mid 1970s.
  2. [2]
    The Digital Equipment Corporation PDP-7 Computer - Soemtron.org
    The PDP-7 was an 18-bit minicomputer with a 1.75 microsecond cycle time, using 'FlipChip' tech, and was a less expensive alternative to earlier PDP computers.
  3. [3]
    [PDF] DIGITAL EQUIPMENT CORPORATION - Bitsavers.org
    Digital Equipment Corporation, located in Maynard, Massachusetts, grew to be a leading minicomputer manufacturer from 1957 to the present, starting in an old ...<|control11|><|separator|>
  4. [4]
    The Digital Equipment Corporation PDP-7 - History and Design.
    The PDP–7 computer was an assembly pioneer being the first DEC machine to use automatic wire wrapping for production, ironically using programs developed on a ...
  5. [5]
    A PDP-7A MINICOMPUTER, Digital Equipment Corporation, 1967.
    The PDP-7A, from 1967, was compact, used integrated circuits, and shaped early computer graphics and time-sharing. It was later used for nuclear analysis.
  6. [6]
    Evolution of the Unix Time-sharing System - Nokia
    The PDP-7 Unix file system. Structurally, the file system of PDP-7 Unix was nearly identical to today's. It had. 1): An i-list: a linear array of i-nodes each ...
  7. [7]
    [PDF] PDP-7_Brochure.pdf - Bitsavers.org
    PROGRAMMED DATA PROCESSOR-7 (PDP-7) is a general purpose, solid state, digital computer designed for high speed data handling in the scientific laboratory, ...Missing: technology | Show results with:technology
  8. [8]
    PDP-7 - Computer History Wiki
    Jun 30, 2025 · The PDP-7, a low-cost, powerful 18-bit minicomputer from DEC, introduced in 1965, was the first wire-wrapped PDP and used Flip-Chip technology.
  9. [9]
    The PDP-7 was used by Thompson for first version of UNIX
    May 30, 2005 · The PDP-7 was a minicomputer which was shipped by Digital Equipment Corporation (DEC) in 1965. Its greatest claim to fame by far is that it ...Missing: symposium | Show results with:symposium
  10. [10]
    [PDF] REFERENCE MANUAL
    The basic PDP-7 inc ludes the central processor and control console; 4096 word core memory; input/output control with device selector (up to 64 I/O connections) ...Missing: architecture | Show results with:architecture
  11. [11]
    [PDF] Architectural Evolution in DEC's 18b Computers - Soemtron.org
    Jul 26, 2003 · The PDP-7's multi-user protection, crude as it was, sufficed for implementation of the first version of UNIX, making the PDP-7 a significant ...
  12. [12]
    [PDF] REFERENCE MANUAL
    From a single source of 115-volt, 60-cycle, single-phase power, the PDP-7 produces circuit operating dc voltages of -15 volts (±1) and +10 volts (±1) which are ...Missing: technology | Show results with:technology
  13. [13]
    [PDF] PDP-7 MAINTENANCE MANUAL - Bitsavers.org
    ... Wire-Wrap. Tool with a 26263 bit for. 24 AWG Wire and 18840 Sleeve. FLIP CHIP ... technique. By repeatedly starting the test program and vibrating. 5-17 ...
  14. [14]
    PDP-7 - Gordon Bell
    A successor to the PDP-4, the PDP-7 used smaller, more conventional system units and was well received in laboratory and data acquisition applications.Missing: development 1963 cycle time
  15. [15]
    [PDF] DECSYS-7_OperMan.pdf - Bitsavers.org
    SYSTEM USE. The DECSYS-7 Operating System has three genera I uses. 1. Editing a system tape or creating a system tape. 2. Editing the working-program group of a ...
  16. [16]
    [PDF] The UNIX Time- Sharing System
    There have been three versions of UNIX. The earliest version (circa 1969–70) ran on the Digital Equipment Cor- poration PDP-7 and -9 computers. The second ...<|control11|><|separator|>
  17. [17]
    PDP-7 UNIX - Computer History Wiki
    Jul 22, 2025 · It was written by Thompson in 1969, initially to experiment with his ideas on file systems, notably his idea on separating the naming function ( ...
  18. [18]
    PDP-7 Unix - Unix Heritage Wiki
    ... cost about $75 for CPU time on the big computer. ... The disk attached to the PDP-7 was fast for its time; it transferred one 18-bit word every 2 microseconds.
  19. [19]
    [PDF] Introduction to the Mumps Language - Computer Science
    Nov 4, 2017 · PDP-7, the same architecture on which Unix was ... The Mumps operating system itself provided the Mumps language interpreter (Mumps was.
  20. [20]
    [PDF] PDP-7 SYMBOLIC ASSEMBLER PROGRAMMING MANUAL
    Memory reference instructions always have an effective operand address. Th is may be the operand address itself or the I address modifier and an address. In ...
  21. [21]
    [PDF] pdp-7 fortran ii programming manual - Bitsavers.org
    language is basic to a thorough understanding of the topics discussed. Information on the assembler language can be obtained from the PDP-7 Symbolic Assembler ...Missing: tools | Show results with:tools
  22. [22]
    From B language to NB to C - Nokia
    The first version of UNIX was written in assembler language, but ... Then he wrote a very simple language he called B, which he got going on the PDP-7.
  23. [23]
    [PDF] and Computers - OSTI.GOV
    Acceptable results for such functions as few-group flux and power profile studies were obtained with the PDP-7 digital computer and a fourth generation analog ...<|separator|>
  24. [24]
    History of the development of medical information systems at the ...
    History of the development of medical information systems at the Laboratory of Computer Science at Massachusetts General Hospital ... PDP-4, then a PDP-7.
  25. [25]
    Boeing's PDP-7a - The Interim Computer Museum
    The PDP-7A functioned as an interactive front-end processor, handling light-pen input and real-time display refresh, while an SDS-930 provided high-precision ...
  26. [26]
    The famous PDP-7 comes to the rescue - Nokia
    The PDP-7 was used to rewrite 'Space Travel' and implement the file system design, which was the natural place for it.
  27. [27]
    Evolution of the Unix Time-sharing System - Nokia
    In the meantime, a rudimentary, core-only version of Unix was written using a cross-assembler on the PDP-7. Most of the time, the machine sat in a corner ...<|control11|><|separator|>
  28. [28]
    Origins and History of Unix, 1969-1995 - catb. Org
    When Bell Labs withdrew from the Multics research consortium, Ken Thompson was left with some Multics-inspired ideas about how to build a file system. He ...
  29. [29]
    Thwarted at DEC, Thriving at Data General - CHM Revolution
    Thwarted at DEC, Thriving at Data GeneralEdson de Castro, the PDP-8's designer, was frustrated by DEC's refusal to approve a family of 16-bit computers.
  30. [30]
    The Minicomputer -- 1959-1979
    The engine propelling DEC's sales and profit growth during this period, the PDP-8, was introduced in the fall of 1965. It, more than any other computer, is ...
  31. [31]
    15. The Minicomputer Revolution - University of Iowa
    By that year, DEC claimed that the PDP-8 was the best selling computer in the world, but in part, they were able to make this claim because IBM was not selling ...
  32. [32]
    Digital Equipment Corporation - CHM Revolution
    DEC was founded in 1957 by Ken Olsen and Harlan Anderson, initially making test equipment, and became a leader in minicomputers, later bought by Compaq.
  33. [33]
    None
    Summary of each segment:
  34. [34]
    Calculate the Value of $72000 in 1965 - DollarTimes
    Adjusted for inflation, $72,000 in 1965 is equal to $728,319 in 2025. Annual inflation over this period was 3.93%.
  35. [35]
    The Digital Equipment Corporation PDP-7 - Options List
    Apparently a basic PDP-7 system could consist solely of a type KA77A processor, 149 core memory stack and a type KA71A I/O package and cost $45,000 in 1965.Missing: goals | Show results with:goals
  36. [36]
    History of DIGITAL EQUIPMENT CORPORATION – FundingUniverse
    ... growth in revenues and profits of between 25 percent and 40 percent per year. Between 1965 and 1967 alone, revenues multiplied sixfold to $4.5 million.<|control11|><|separator|>
  37. [37]
    Historical Interlude: From the Mainframe to the Minicomputer Part 3 ...
    Dec 11, 2014 · In 1965, DEC introduced the PDP-8 with 4,000 words of memory and a teletype for user input for just $18,000. Within just a few years, the price ...
  38. [38]
    Is it possible to get a pdp7 [closed] - Retrocomputing Stack Exchange
    Jan 10, 2019 · Yeah, sorry, it was right after I posted this that I found a list of all surviving pdp7s there are 5. Oops. user11220. – user11220. 2019-01-10 ...
  39. [39]
    UNIX Version 0, Running On A PDP-7, In 2019 - Hackaday
    Nov 17, 2019 · This primordial version on the original hardware is all the more remarkable because unlike its younger siblings very few PDP-7s have survived.
  40. [40]
    PDP-7 minicomputer - 102691359 - CHM - Computer History Museum
    Item Details ; Date: 1964 (Made) ; Type: Physical Object ; Catalogue number: 102691359 ; Other identifying number: PDP-7 (number) 2500 (number) 5098 (serial number)
  41. [41]
    Restoration : TAPE19 : Max Burnet
    May 13, 2023 · I have a collection of all the early DEC computers that came to Australia. ie PDP-5, PDP-6, PDP-7, PDP-8, PDP-9, PDP-10 etc. Yours sincerely ...
  42. [42]
    [PDF] Preserving Computing's Past: Restoration and Simulation - SIMH
    It describes a simulation framework called SIM, which has been used to implement simulators for the PDP-8, PDP-11,. PDP-4/7/9/15, and Nova minicomputers.
  43. [43]
    The bitsavers main page
    As of July, 2025 there are over 179000 files including over 8.5 million text pages in the 1.73tb archive. · People are downloading the ENTIRE ...Index of /pdf · Index of /bits · Components Archive · Index of /magazinesMissing: 7 | Show results with:7
  44. [44]
    PDP-7 / PDP-9 Software Preservation in 2025
    Mar 21, 2025 · DECSYS-7. The DECtape FORTRAN system. · DECTRIEVE-7. Looks to be a minimal software loader for DECtapes. · PDP-7 MAINDEC tapes · BUS-PAK II ...
  45. [45]
    PDP-7 Simulator Configuration - SIMH
    The PDP-7 simulator has 4KW-32KW CPU/memory, Type 649 console, Type 444 paper tape reader, Type 647B line printer, Type 550/555 DECtape, Type 24 drum, and RB09 ...Missing: nuclear physics
  46. [46]
    DoctorWkt/pdp7-unix - GitHub
    pdp7-unix is a project to resurrect Unix on the PDP-7 from scans of the original assembly code done by Norman Wilson. The scans of PDP-7 Unix are in the Unix ...Missing: 2011 | Show results with:2011
  47. [47]
    Software Kits - SIMH
    DECSys for the PDP-4 and PDP-7 - requires SimH V3.6-1 or later (courtesy of Harlan Lefevre). SIM8 for the PDP-7 (courtesy of the author, David J Waks). ESI ...Missing: v0 | Show results with:v0<|separator|>
  48. [48]
    KiCAD Templates for DEC FLIP CHIP Modules - GitHub
    This repo contains KiCAD templates for building boards that are physically compatible with Digital Equipment Corporation's FLIP CHIP modules.
  49. [49]
    Museum gets Unix version 0 running on a DEC PDP-7 - Fudzilla.com
    Nov 21, 2019 · The Living Computers museum in Seattle has got a DEC PDP-7 minicomputer running version 0 of Unix just in time for the operating system's 50th birthday.
  50. [50]
    DEC PDP-8/I Restoration - Rhode Island Computer Museum
    We will need to finish cleaning the modules in the CPU, the TC01 Dectape controller, and all 5 of the TU55 tape drives. We connected the power supply to the CPU ...
  51. [51]
    [PDF] Digital Archaeology: Rescuing Neglected and Damaged Data ...
    It has become apparent that archiving digital material has its own problems in varied data structures, programs and limited documentation, much of which ...
  52. [52]
    Recovery of vintage IBM tape archive - Facebook
    Aug 7, 2025 · We started with a basic PDP 11/34 with two RK05 drives, 128KW memory, LA36 console and LA120 printer. Later we added a programmable front panel, ...Sharing experiences with PDP-11 systems in the 70s and 80sRestoring PDP-11 systems and seeking advice - FacebookMore results from www.facebook.com