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