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246 lines
14 KiB
Text
246 lines
14 KiB
Text
==Phrack Inc.==
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Volume Two, Issue 18, Phile #4 of 11
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-------------------------------------------------------------------------
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- -
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- -
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- PRIMOS: -
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- NETWORK COMMUNICATIONS -
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- -
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- PRIMENET, RJE, DPTX -
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- -
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- -
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- Presented by Magic Hasan June 1988 -
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-------------------------------------------------------------------------
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PRIME's uniform operating system, PRIMOS, supports a wide range of
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communications products to suit any distributed processing need. The PRIMENET
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distributed networking facility provides complete local and remote network
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communication services for all PRIME systems. PRIME's Remote Job Entry (RJE)
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products enable multi-user PRIME systems to emulate IBM, CDC, Univac,
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Honeywell and ICL remote job entry terminals over synchronous communication
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lines. PRIME's Distributed Processing Terminal Executive (DPTX) allows users
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to construct communication networks with PRIME and IBM-compatible equipment.
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PRIMENET
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--------
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PRIMENET provides complete local and remote network communication services
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for all PRIME systems. PRIMENET networking software lets a user or process on
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one PRIME system communicate with any other PRIME system in the network
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without concern for any protocol details. A user can log in to any computer
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in the network from any terminal in the network. With PRIMENET, networking
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software processes running concurrently on different systems can communicate
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interactively. PRIMENET allows transparent access to any system in the
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network without burdening the user with extra commands.
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PRIMENET has been designed and implemented so that user interface is simple
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and transparent. Running on a remote system from a local node of the network
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or accessing remote files requires no reprogramming of user applications or
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extensive user training. All the intricacies and communication protocols of
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the network are handled by the PRIMENET software. For both the local and
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remote networks, PRIMENET will allow users to share documents, files, and
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programs and use any disk or printer configured in the network.
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For a local network between physically adjacent systems, PRIME offers the
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high-performance microprocessor, the PRIMENET Node Controller (PNC). The
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controller users direct memory access for low overhead and allows loosely
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coupled nodes to share resources in an efficient manner. The PNCs for each
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system are connected to each other with a coaxial cable to form a high-speed
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ring network, with up to 750 feet (230 meters) between any two systems.
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Any system in the PNC ring can establish virtual circuits with any other
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system, making PNC-based networks "fully connected" with a direct path between
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each pair of systems. The ring has sufficient bandwidth (1 MB per second) and
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addressing capability to accommodate over 200 systems in a ring structure;
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however, PRIMENET currently supports up to sixteen systems on a ring to
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operate as a single local network.
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The PRIMENET Node Controller is designed to assure continuity of operation
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in the event that one of the systems fails. One system can be removed from
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the network or restored to on-line status without disturbing the operations of
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the other system. An active node is unaware of messages destined for other
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nodes in the network, and the CPU is notified only when a message for that
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node has been correctly received.
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Synchronous communications over dedicated leased lines or dial-up lines is
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provided through the Multiple Data Link Controller (MDLC). This controller
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handles certain protocol formatting and data transfer functions normally
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performed by the operating system in other computers. The controller's
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microprogrammed architecture increases throughput by eliminating many tasks
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from central processor overhead.
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The communications controller also supports multiple protocols for
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packet-switched communications with Public Data Networks such as the United
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States' TELENET and TYMNET, the Canadian DATAPAC, Great Britain's
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International Packet Switching Service (IPSS), France's TRANSPAC, and the
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European Packet Switching Network, EURONET. Most Public Data Networks require
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computers to use the CCITT X.25 protocol to deal with the management of
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virtual circuits between a system and others in the network. The synchronous
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communications controller supports this protocol. PRIME can provide the X.25
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protocol for use with the PRIMENET networking software without modification to
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the existing hardware configuration.
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PRIMENET software offers three distinct sets of services. The
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Inter-Program Communication Facility (IPCF) lets programs running under the
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PRIMOS operating system establish communications paths (Virtual circuits) to
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programs in the same or another PRIME system, or in other vendors' systems
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supporting the CCITT X.25 standard for packet switching networks. The
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Interactive Terminal Support (ITS) facility permits terminals attached to a
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packet switching network, or to another PRIME system, to log-in to a PRIME
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system with the same capabilities they would have if they were directly
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attached to the system. The File Access Manager (FAM) allows terminal users
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or programs running under the PRIMOS operating system to utilize files
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physically stored on other PRIME systems in a network. Remote file operations
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are logically transparent to the application program. This means no new
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applications and commands need to be learned for network operation.
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The IPCF facility allows programs in a PRIME computer to exchange data with
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programs in the same computer, another PRIME computer, or another vendor's
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computer, assuming that that vendor supports X.25. This feature is the most
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flexible and powerful one that any network software package can provide. It
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basically allows an applications programmer to split up a program, so that
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different pieces of the program execute on different machines a network. Each
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program component can be located close to the resource (terminals, data,
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special peripherals, etc.) it must handle, decode the various pieces and
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exchange data as needed, using whatever message formats the application
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designer deems appropriate. The programmer sees PRIMENET's IPCF as a series
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of pipes through which data can flow. The mechanics of how the data flows are
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invisible; it just "happens" when the appropriate services are requested. If
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the two programs happen to end up on the same machine, the IPCF mechanism
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still works. The IPCF offers the following advantages:
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1) The User does not need to understand the detailed
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mechanisms of communications software in order to
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communicate.
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2) Calls are device-independent. The same program will
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work over physical links implemented by the local node
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controller (local network), leased lines, or a packet
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network.
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3) Programs on one system can concurrently communicate
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with programs on other systems using a single
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communications controller. PRIMENET handles all
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multiplexing of communications facilities.
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4) A single program can establish multiple virtual
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circuits to other programs in the network.
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PRIMENET's ITS facility allows an interactive terminal to have access to
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any machine in the network. This means that terminals can be connected into
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an X.25 packet network along with PRIME computers. Terminal traffic between
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two systems is multiplexed over the same physical facilities as inter-program
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data, so no additional hardware is needed to share terminals between systems.
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This feature is ordinarily invisible to user programs, which cannot
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distinguish data entering via a packet network from data coming in over AMLC
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lines. A variant of the IPCF facility allows users to include the terminal
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handling protocol code in their own virtual space, thus enabling them to
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control multiple terminals on the packet network within one program.
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Terminals entering PRIMOS in this fashion do not pass through the usual log-in
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facility, but are immediately connected to the application program they
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request. (The application program provides whatever security checking is
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required.)
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The result is the most effective available means to provide multi-system
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access to a single terminal, with much lower costs for data communications and
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a network which is truly available to all users without the expense of
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building a complicated private network of multiplexors and concentrators.
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By utilizing PRIMENET's File Access Manager (FAM), programs running under
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PRIMOS can access files on other PRIME systems using the same mechanisms used
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to access local files. This feature allows users to move from a single-system
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environment to a multiple-system one without difficulty. When a program and
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the files it uses are separated into two (or more) systems the File Access
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Management (FAM)is automatically called upon whenever the program attempts to
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use the file. Remote file operations are logically transparent to the user
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or program.
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When a request to locate a file or directory cannot be satisfied locally,
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the File Access Manager is invoked to find the data elsewhere in the network.
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PRIMOS initiates a remote procedure call to the remote system and suspends the
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user. This procedure call is received by an answering slave process on the
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remote system, which performs the requested operation and returns data via
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subroutine parameters. The slave process on the remote system is dedicated to
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its calling master process (user) on the local system until released. A
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master process (user) can have a slave process on each of several remote
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systems simultaneously. This means that each user has a dedicated connection
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for the duration of the remote access activity so many requests can be
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handled in parallel.
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FAM operation is independent of the specific network hardware connecting
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the nodes. There is no need to rewrite programs or learn new commands when
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moving to the network environment. Furthermore, the user need only be
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logged-in to one system in the network, regardless of the location of the
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file. Files on the local system or remote systems can be accessed dynamically
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by file name within a program, using the language-specific open and close
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statements. No external job control language statements are needed for the
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program to access files. Inter-host file transfers and editing can be
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performed using the same PRIMOS utilities within the local system by
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referencing the remote files with their actual file names.
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REMOTE JOB ENTRY
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----------------
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PRIME's Remote Job Entry (RJE) software enables a PRIME system to emulate
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IBM, CDC, Univac, Honeywell and ICL remote job entry terminals over
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synchronous communication lines. PRIME's RJE provides the same communications
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and peripheral support as the RJE terminals they emulate, appearing to the
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host processor to be those terminals. All PRIME RJE products provide three
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unique benefits:
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* PRIME RJE is designed to communicate with multiple
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remote sites simultaneously.
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* PRIME RJE enables any terminal connected to a PRIME system to
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submit jobs for transmission to remote processors, eliminating the
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requirement for dedicated terminals or RJE stations at each
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location.
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* PRIME's mainframe capabilities permit concurrent running of RJE
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emulators, program development and production work.
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PRIME's RJE supports half-duplex, point-to-point, synchronous
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communications and operates over dial-up and dedicated lines. It is fully
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supported by the PRIMOS operating system.
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DISTRIBUTED PROCESSING TERMINAL EXECUTIVE (DPTX)
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------------------------------------------------
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PRIME's Distributed Processing Terminal Executive (DPTX) allows users to
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construct communication networks with PRIME and IBM-compatible equipment.
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DPTX conforms to IBM 3271/3277 Display System protocols, and can be integrated
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into networks containing IBM mainframes, terminals and printers without
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changing application code or access methods and operates under the PRIMOS
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operating system.
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DPTX is compatible with all IBM 370 systems and a variety of access methods
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and teleprocessing monitors: BTAM, TCAM, VTAM, IMS/VS, CIC/VS, and TSO. They
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provide transmission speeds up to 9600 bps using IBM's Binary Synchronous
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Communications (BSC) protocol.
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DPTX is comprised of three software modules that allow PRIME systems to
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emulate and support IBM or IBM compatible 3271/3277 Display Systems. One
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module, Data Stream Compatibility (DPTX/DSC), allows the PRIME system to
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emulate the operation of a 3271 on the IBM system. This enables both terminal
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user and application programs (interactive or batch) on the PRIME System to
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reach application programs on an IBM mainframe. A second module, Terminal
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Support Facility (DPTX/TSF), allows a PRIME system to control a network of IBM
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3271/3277 devices. This enables terminal users to reach application programs
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on a PRIME computer. The third module, Transparent Connect Facility
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(DPTX/TCF), combines the functions of modules one and two with additional
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software allowing 3277 terminal users to to reach programs on a IBM mainframe,
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even though the terminal subsystem is physically connected to a PRIME system,
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which is connected to an IBM system.
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PRIMOS offers a variety of different Communication applications. Being
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able to utilize these applications to their fullest extent can make life easy
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for a Primos "enthusiast." If you're a beginner with Primos, the best way to
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learn more, as with any other system, is to get some "hands-on" experience.
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Look forward to seeing some beginner PRIMOS files in the near future. -MH
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------------------------------------------------------------------------------
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Special thanks to PRIME INC. for unwittingly providing the text for this
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article.
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===============================================================================
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