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34-639: The 18-bit PDP systems preceding the PDP-9 are the PDP-1 , PDP-4 and PDP-7 . Its successor is the PDP-15 . The PDP-9, which is "two metres wide and about 75cm deep," is approximately twice the speed of the PDP-7. It was built using discrete transistors, and has an optional integrated vector graphics terminal. The PDP-9 has a memory cycle time of 1 microsecond, and weighs about 750 pounds (340 kg). The PDP-9/L has

68-499: A system console which allowed for direct interaction, as opposed to previous computers, which required the use of punched card as a primary interface for programmers debugging their programs. Members of MIT's Tech Model Railroad Club , "the very first hackers at MIT", reveled in the interactivity afforded by the console, and were recruited by Marvin Minsky to work on this and other systems used by Minsky's AI group. Designed at

102-457: A decade. Significant pieces of the TX-0 are held by MIT Lincoln Laboratory. In 1983, the TX-0 was still running and is shown running a maze application in the first episode of Computer Chronicles . As part of its use in artificial intelligence research, the computer was used to write simple western playlets and was featured in the 1961 CBS television documentary "The Thinking Machine", and in

136-603: A memory cycle time of 1.5 microseconds, and weighs about 900 pounds (410 kg). It is DEC's first microprogrammed machine. A typical configuration included: Among the improvements of the PDP-9 over its PDP-7 predecessor are: User/university-based research projects for extending the PDP-9 include: The system came with an OS that functions as single-user keyboard monitor, called ADSS (ADvanced Software System). DECsys provided an interactive, single-user, program development environment for Fortran and assembly language programs. Both FORTRAN II and FORTRAN IV were implemented for

170-457: A short time selling "lab modules" in the form of simple logic elements from the TX-2 design, the newly formed Digital Equipment Corporation (DEC) decided to produce a "cleaned up" TX-0 design, and delivered it in 1961 as the PDP-1 . A year later, DEC donated the engineering prototype PDP-1 machine to MIT. It was installed in the room next to TX-0, and the two machines would run side-by-side for almost

204-573: 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 is the system's standard input/output solution, a punched tape reader and writer. The PDP-1 weighs about 730 kg (1,600 lb). The design of the PDP-1 is based on the pioneering TX-0 and TX-2 computers, designed and built at MIT Lincoln Laboratory . Benjamin Gurley

238-477: A sophisticated text-based program with some features specifically oriented toward the efficient coding of baroque music . Several hours of music were prepared for it, including Bach fugues , all of Mozart's Eine kleine Nachtmusik , the Ode to Joy movement concluding Beethoven's Symphony No. 9 , Christmas carols, and numerous popular songs. Only three PDP-1 computers are still known to exist, and all three are in

272-430: Is a point plotting display device capable of addressing 1024 by 1024 addressable locations at a rate of 20,000 points per second. A special "Display One Point On CRT" instruction is used to build up images, which have to be refreshed many times per second. The CRT, which was originally developed for use in radar, is 16 inches (41 cm) in diameter and uses a long-persistence P7 phosphor . A light pen can be used with

306-432: Is tedious to physically edit. This inspired the creation of text-editing programs such as Expensive Typewriter and TECO . Because it is equipped with online and offline printers that were based on IBM electric typewriter mechanisms, it is capable of what, in 1980s terminology, would be called " letter-quality printing " and therefore inspired TJ-2 , arguably the first word processor . The console typewriter, known as

340-745: Is the first computer in Digital Equipment Corporation 's PDP series and was first produced in 1959. It is famous for being the most important computer in the creation of hacker culture at the Massachusetts Institute of Technology , Bolt, Beranek and Newman and elsewhere. The PDP-1 is the original hardware for playing history's first game on a minicomputer , Steve Russell 's Spacewar! The PDP-1 uses an 18-bit word size and has 4096 words as standard main memory (equivalent in bit size to 9,216 eight-bit bytes , but in character size to 12,388 bytes since

374-596: Is the first commercial computer that focuses on interaction with the user rather than just the efficient use of computer cycles. The first ever reference to malicious hacking is ' telephone hackers ' in MIT 's student newspaper, The Tech , of hackers tying up the lines with Harvard , configuring the PDP-1 to make free calls, war dialing and accumulating large phone bills. The PDP-1 uses fanfold punched paper tape as its primary storage medium. Unlike punched card decks, which could be sorted and re-ordered, paper tape

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408-841: Is to output text to punched paper tape using the PDP-1's "high speed" (60-character-per-second) Teletype model BRPE punch, then to hand carry the tape to a Flexowriter for offline printing. In later years, DECtape drives were added to some PDP-1 systems, as a more convenient method of backing up programs and data, and to enable early time-sharing . This latter application usually requires a secondary storage medium for swapping programs and data in and out of core memory, without requiring manual intervention. For this purpose, DECtapes are far superior to paper tapes, in terms of reliability, durability, and speed. Early hard disks were expensive and notoriously unreliable; if available and working, they are used primarily for speed of swapping, and not for permanent file storage. The Type 30 Precision CRT display

442-475: The Computeriter , was provided by Soroban Engineering . It is an adapted IBM Model B Electric typewriter mechanism, modified by the addition of switches to detect key presses, and solenoids to activate the typebars . It uses a traditional typebar mechanism, not the "golfball" IBM Selectric typewriter mechanism, which was not introduced until the next year. Lettercase is selected by raising and lowering

476-534: The MIT Lincoln Laboratory largely as an experiment in transistorized design and the construction of very SMALL core memory systems, the TX-0 was essentially a transistorized version of the equally famous Whirlwind , also built at Lincoln Lab. While the Whirlwind filled an entire floor of a small flat, TX-0 fit in a single reasonably sized room and yet was somewhat faster. Like the Whirlwind,

510-499: The MiSTer project as well, and binary image of paper tapes of the software exist in the bitsavers.org archives. TX-0 The TX-0 , for T ransistorized E x perimental computer zero , but affectionately referred to as tixo (pronounced "tix oh"), was an early fully transistorized computer and contained a then-huge 64 K of 18-bit words of magnetic-core memory . Construction of the TX-0 began in 1955 and ended in 1956. It

544-550: The FIO-DEC character coding used by the PDP-1. Like the console typewriter, these are built around a typing mechanism that is mechanically the same as an IBM Electric typewriter . However, Flexowriters are highly reliable and were often used for long unattended printing sessions. Flexowriters have electromechanical paper tape punches and readers which operate synchronously with the typewriter mechanism. Typing rates are about ten characters per second. A typical PDP-1 operating procedure

578-459: The PDP-1 quickly replaced the TX-0 as the favorite machine among the budding hacker culture , and served as the platform for a long list of computing innovations. This list includes one of the earliest digital video games, Spacewar! , the first text editor , the first word processor , the first interactive debugger , the first credible computer chess program, one of the very earliest time-sharing systems ( BBN Time-Sharing System ), and some of

612-701: The PDP-9. MUMPS was originally developed on the PDP-7, and ran on several PDP-9s at the Massachusetts General Hospital . The PDP-7 , of which 120 were sold, was described as "highly successful". The PDP-9 sold 445 units. Both have submodels, the PDP-7A and the PDP-9/L, neither of which accounted for a substantial percentage of sales. This minicomputer -related article is a stub . You can help Misplaced Pages by expanding it . PDP-1 The PDP-1 ( Programmed Data Processor-1 )

646-415: The TX-0 was equipped with a vector display system, consisting of a 12-inch oscilloscope with a working area of 7 by 7 inches connected to the 18-bit output register of the computer, allowing it to display points and vectors with a resolution up to 512×512 screen locations. The TX-0 was an 18-bit computer with a 16-bit address range. The first two bits of the machine word designated the instruction, and

680-626: The TX-2 project. After a time, the TX-0 was no longer considered worth keeping at Lincoln Lab, and was "loaned" (semi-permanently) to the MIT Research Laboratory of Electronics (RLE) in July 1958, where it became a centerpiece of research that would eventually evolve into the MIT Artificial Intelligence Lab and the original computer hacker culture . Delivered from Lincoln Laboratory with only 4K of core,

714-462: The Type 30 to pick points on the display. An optional character generator and hardware for line and curve generation are available. MIT hackers also used the PDP-1 for playing music in four-part harmony, using some special hardware – four flip-flops directly controlled by the processor (the audio signal is filtered with simple RC filters ). Music was prepared via Peter Samson 's Harmony Compiler ,

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748-571: The collection of the Computer History Museum (CHM). One is the prototype formerly used at MIT, and the other two are production PDP-1C machines. One of the latter, serial number 55 (the last PDP-1 made) has been restored to working order, is on exhibit, and is demonstrated on two Saturdays every month. The demonstrations include: Software simulations of the PDP-1 exist in SIMH and MESS , hardware recreation through FPGA exists for

782-507: The data word. Signed numbers are represented in ones' complement . The PDP-1 has computing power roughly equivalent to a 1996 pocket organizer and a little less memory. The PDP-1 uses 2,700 transistors and 3,000 diodes. It is built mostly of DEC 1000-series System Building Blocks , using micro-alloy and micro-alloy diffused transistors with a rated switching speed of 5   MHz. The System Building Blocks are packaged into several 19-inch racks . The racks are themselves packaged into

816-649: The earliest computerized music. At the Computer History Museum TX-0 alumni reunion in 1984, Gordon Bell said DEC's products developed directly from the TX-2 , the successor to the TX-0 which had been developed at what Bell thought was a bargain price at the time, about US$ 3 million . At the same meeting, Jack Dennis said Ben Gurley's design for the PDP-1 was influenced by his work on the TX-0 display. The PDP-1 sold in basic form for US$ 120,000 (equivalent to US$ 1,223,519 in 2023). BBN's system

850-486: The first large magnetic-core memory bank. However, the design was never approved and the TX-1 was never built. Instead, the TX-0 was designed for the same purpose, except using transistors. With the successful completion of the TX-0, work turned immediately to the much larger and far more complex TX-2 , completed in 1958. Since core memory was very expensive at the time, several parts of the TX-0 memory were cannibalized for

884-445: The machine no longer needed 16 bits to represent a storage address. After about a year and a half, the number of instruction bits was doubled to four, allowing a total of 16 instructions, and an index register was added. This dramatically improved programmability of the machine, but still left room for a later memory expansion to 8K (the four instruction bits and one-bit indexing flag left 13 bits for addressing). This newly modified TX-0

918-442: The massive type basket. The Soroban is equipped with a two-color inked ribbon (red and black), and the interface allows color selection. Programs commonly use color-coding to distinguish user input from machine responses. The Soroban mechanism is unreliable and prone to jamming, particularly when shifting case or changing ribbon color. Offline devices are typically Friden Flexowriters that have been specially built to operate with

952-408: The remaining 16 bits are used to specify the memory location or operand for the special "operate" instruction. These two bits created four possible instructions, which included store, add, and conditional branch instructions as a basic set. Wesley A. Clark designed the logic and Ken Olsen oversaw the engineering development. Initially a vacuum-tube computer named TX-1 was being designed to test

986-425: The system actually divides an 18-bit word into three six-bit characters), upgradable to 65,536 words. The magnetic-core memory 's cycle time is 5.35 microseconds (corresponding roughly to a clock speed of 187 kilohertz ); consequently most arithmetic instructions take 10.7 microseconds (93,458 operations per second) because they use two memory cycles: the first to fetch the instruction, the second to fetch or store

1020-433: Was quickly followed by orders from Lawrence Livermore and Atomic Energy of Canada (AECL), and eventually 53 PDP-1s were delivered until production ended in 1969. All of these machines were still being actively used in 1970, and several were eventually saved. MIT's example was donated to The Computer Museum, Boston , and from there ended up at the Computer History Museum (CHM). A late version of Spacewar! on paper tape

1054-604: Was still tucked into the case. PDP-1 #44 was found in a barn in Wichita, Kansas in 1988, apparently formerly owned by one of the many aviation companies in the area, and rescued for the Digital Historical Collection, also eventually ending up at the CHM. AECL's computer was sent to Science North , but was later scrapped. The launch of the PDP-1 marked a radical shift in the philosophy of computer design: it

PDP-9 - Misplaced Pages Continue

1088-661: Was the lead engineer on the project. After showing a prototype at the Eastern Joint Computer Conference in December 1959, DEC delivered the first PDP-1 to Bolt, Beranek and Newman (BBN) in November 1960, and it was formally accepted in early 1961. In September 1961, DEC donated the PDP-1 to MIT, where it was placed in the room next to its ancestor, the TX-0 computer, which was by then on indefinite loan from Lincoln Laboratory. In this setting,

1122-428: Was used continually through the 1960s at MIT . The TX-0 incorporated around 3,600 Philco high-frequency surface-barrier transistors , the first transistor suitable for high-speed computers. The TX-0 and its direct descendant, the original PDP-1 , were platforms for pioneering computer research and the development of what would later be called computer " hacker " culture. For MIT, this was the first computer to provide

1156-422: Was used to develop a huge number of advances in computing, including speech and handwriting recognition , as well as the tools needed to work on such projects, including text editors and debuggers . Meanwhile the TX-2 project was running into difficulties of its own, and several team members decided to leave the project at Lincoln Lab and start their own company - Digital Equipment Corporation (DEC). After

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