PicLan Technical Overview - June 3, 1996

Updated September 9, 1997

In 1991, PicLan was introduced at the Spectrum trade show to a somewhat surprised Pick community. Indeed, Spectrum was the first time that anyone except the developers had ever seen the product. Since then, PicLan has been installed onto over 3000 Pick systems.

PicLan is software that allows a native Pick system to operate in a networked environment. In designing and implementing PicLan, the goal was to provide a direct network connection to native Pick platforms and to provide for maximum performance and versatility. This meant that the usual serial hardware could not be used for the network connection. Instead, a high-performance Ethernet adapter was chosen and installed within the Pick system. This in conjunction with a software driver developed in 'C' is the core of the Piclan product.

PicLan is available for a number of native Pick hosts, and supports a variety of network environments that support DOS and DOS/Windows workstations. In general, all PicLan hosts are equal and all networks are equal in regard to how PicLan interacts with them. If you are deciding on what type of Pick host to buy and you want to use PicLan with it, your decision should probably be made based on the Pick host and not on the PicLan implementation. The PicLan product is virtually identical for all supported Pick hosts and is actually compiled from the same driver source code. The same logic holds true for which type of network environment you should implement. PicLan was originally designed to work with Novell NetWare. Recent enhancements to the PicLan product now allow PicLan to operate in conjunction with many different network environments.

PicLan is not currently available for Pick hosts that run in conjunction with Unix. In the past, Pick on top of Unix provided an easy path to support a larger numbers of users than many native Pick implementations could handle. This is no longer the case for many Pick installations. PicLan is now available supporting nine native Pick implementations that support 128 to 256 or more active users. If you are looking at Pick/Unix implementations and plan on actually using Unix for more than just a place to run Pick, you should probably not be looking at PicLan. If on the other hand, you are looking for an environment to run Pick applications on a network, native Pick and PicLan are often a better choice. Not only is native Pick easier to maintain, and less expensive than Pick/Unix solutions, PicLan provides DOS network connectivity that is simpler, less expensive, and more robust that Unix network solutions.

The PicLan Network Interface

Before describing how PicLan can connect a Pick system to a network, it is important to realize just what a network is. A network is a generalized interconnection of computing devices. Unlike serial terminal and printer cabling where each peripheral can only communicate with a central computer system, any network device can communicate with any other network device in a distributed fashion. Serial connections typically support only a single "connection" on a single cable. Networks support many connections on a single cable. Serial connections are relatively slow and are capable of moving 1000 to 2000 characters of data per second. Network connections are much faster and can move from 250,000 to over 10,000,000 characters per second. Serial connections can extend several hundred feet from the central system and further though the use of telephone lines, modems, and multiplexers. Network connections can typically extend several thousand feet, and further though the use of wide area network interfaces, telephone lines, modems, and other means to extend a network to literally cover the globe.

PicLan connects a Pick system directly to a "network". PicLan is not just software, but also hardware that is installed in your Pick system and which connects directly to a local area network. Once a Pick system is connected to a network, Pick functions become available to any user that is connected to the network. In network terminology, the Pick system becomes a Pick "server" providing Pick-type services to network users or clients. The PicLan network connection takes advantage of all of the characteristics of a network. A single physical connection to the network can support a large number of users, any user on the network can communicate with the Pick system, and communications take place at network speeds.

PicLan Functions:

PicLan network connections provide more functionality than async serial connections. With async connections, you can run a single terminal "connection". PicLan can support terminal connections, as well as network connections for other purposes.

PicLan Terminal Services

PicLan terminal services consist of the ability to connect to a Pick system as a "serial port" user. In reality, there is no serial port involved, but the Pick system views the user as if they were connected to a serial line. In this environment, the user is not running at a "baud" rate, but is instead running at network speed. The network is usually faster than either the Pick system can generate data or the DOS workstation can display the data, so the actual throughput is rarely determined by the network itself. Measured throughputs as high as 350,000 characters per second (the equivalent of 3,500,000 baud) have been measured and 300,000 to 800,000 baud is quite common. PicLan terminal services also support "port contention", allowing a limited number of Pick ports to be shared among a larger number of DOS workstations, and "multiple session support" where a single workstation can connect to multiple ports at the same time.

The PicLan package currently includes three different terminal emulator programs. One emulator is a DOS-based multi-session emulator supporting 132 column display modes, 44,50,60 line display modes, overlapped session windows, execution of DOS commands under Pick control, as well as other features. The second emulator is a single-session DOS program which is a simplified version of the multi-session emulator. The third emulator is a Windows program, although the DOS emulator can also be run within Microsoft Windows.

PicLan is also compatible with a number of third-party terminal emulation packages including AccuTerm, Via Duct, TERMiTE, WinLink, Wintegrate, Via ODBC, Liberty ODBC, and others. A PicLan DOS Software Developers Kit (SDK) is available to terminal emulation vendors and Pick applications developers with their own DOS or Windows terminal emulator programs who wish to include PicLan connection support in their packages.

Piclan File Transfer Services

PicLan also supports transferring data between Pick and DOS. Typically, a terminal connection is not used to transfer files with PicLan. Instead, the network is used to create a separate "file transfer" connection that actually hosts the file transfer operation. This allows a DOS workstation to upload or download data to a Pick host even without logging on to the Pick system. File transfer operations typically operate at from 20,000 to 50,000 bytes per second, depending primarily on the speed of the Pick host and the speed of the workstation.

PicLan Printer Services

PicLan supports sharing of printers between Pick and DOS. DOS applications can direct printer output to printers attached to the Pick system without requiring a terminal session. Print re-direction functions are quite fast and add little overhead to a Pick host.

Pick applications can also direct printer output to printers attached to the users workstation. This "slave" printer output does not use the same channel as the users terminal connection, so printing and terminal operations do not interfere with each other. PicLan "slave" print jobs do not use Pick ports. PicLan "slave" print jobs are also generated as normal print jobs addressed to a Pick spooler form queue, so special "slave" printer escape sequences are not required within the Pick application.

Visual Basic File Sharing and RPC

PicLan includes Microsoft Visual Basic libraries that allow Visual Basic applications to share Pick files. Functions supporting Pick Basic file I/O operations like OPEN, READ, WRITE, DELETE, SELECT, and READNEXT are all available to Visual Basic applications. Support for Pick item locks and dynamic array operators are also included. Visual Basic programs can also call Pick subroutines for additional processing.

Optional PicLan Functions

The three core PicLan functions, terminal emulation, file transfer, and printer re-direction, described above are included in every PicLan configuration as a part of the base package. With some PicLan implementations (AP/Pro, Mentor/Pro, R91) these options are actually included in the base package. With other PicLan implementations, these options require an added-cost PicLan license.

PicLan DOS Services Gateway Functions

The PicLan DOS Services Gateway provides additional file transfer and printer sharing capabilities between Pick and a DOS network. The DOS Services Gateway is a separate software program that executes on a dedicated DOS workstation or on a Windows workstation as a background application.

PicLan DOS Services Gateway file transfer functions give Pick applications the ability to access DOS data files stored either locally on the DOS Services Gateway system or accessible to the DOS Services Gateway system over a DOS network connection. Any DOS file accessible to the DOS Services Gateway system is accessible under Pick application control. The Pick application does not need to be run from a network-connected workstation to use DOS Services Gateway functions. DOS Services Gateway file transfer and access functions include:

In addition, Pick BASIC subroutines are available to directly manipulate the DOS file system. These subroutine include functions to: PicLan DOS Services Gateway printing functions allow for more flexible sharing of printing resources between Pick and network attached printers. With the base PicLan package, DOS users can print on Pick attached printers using a PicLan printer re-direction TSR which is loaded onto each DOS workstation. Pick users can also print on DOS-attached "slave" printers. With the DOS Services Gateway, Pick spooler form queues can be re-directed to network printer form queues located on one or several NetWare file servers, or accessable as Windows network paths. This allows a Pick host to use printers controlled by NetWare, Windows for Workgroups, Windows 95, and Windows NT. With NetWare server-based networks, NetWare form queues can also be re-directed to Pick form queues. All printer re-direction using the DOS Services Gateway is processed by background tasks on the Pick system, and do do not utilize additional Pick ports, regardless of the number of printers being serviced.

PicLan printer sharing with NetWare and Windows via a DOS Services Gateway can be best described as "seamless". Pick applications can generate job to the Pick spooler and DOS/Windows applications can generate jobs to the NetWare or Windows spooler without needing to know where the printer is actually located.

Pick to Pick Functions

PicLan also provides functions that are available on a peer to peer basis between multiple Pick systems connected to a network. PicLan Pick to Pick functions allow multiple Pick systems to share data and resources using a high-performance network connection.

Pick to Pick functions include the following capabilities:

Terminal Passthru:

Pick async and console users can login to other networked systems by running a PicLan TCL command.
File Transfer:
Pick applications can remote copy data from system to system.
File Access:
Pick applications can remote open and manipulate data files located on another system with BASIC subroutine calls.
Remote Proceedure Calls:
Pick application can call BASIC subroutines resident on a distant system passing parameters.
Printer Sharing:
Pick form queues can be routed from system to system transparently.
Pick to Pick functions are available even between Pick hosts of different manufacturer and different operating system versions and vendors.

PicLan Pick Hosts

PicLan is available supporting a number of native Pick hosts. The PicLan product is extremely similar from host to host and is actually built using a single software source-code base. Each underlying Pick host is different however, so minor differences in PicLan functions and features do exist.

Alpha Microsystems Pick/64+ 2.2:

PicLan supports Pick/64+ releases 2.2 with up to 130 network users. A single Ethernet network adapter is installed in the Pick system.
Alpha Microsystems Pick/64+ 2.3:
PicLan supports Pick/64+ release 2.3 with up to 190 network users. A single Ethernet network adapter is installed in the Pick system.
General Automation R91:
PicLan supports R91 release 8.1(09) and later with up to 256 network users. A single ArcNET network adapter is installed in the Pick system. PicLan can also be used as a transport medium for GALAN Pick to Pick connections.
General Automation/SunRiver/ADDS PC/OS:
PicLan supports PC/OS release 3.0M with up to 126 network users. A single Ethernet network adapter is installed in the Pick system.
General Automation/SunRiver/ADDS Mentor/Pro:
PicLan supports Mentor/Pro release 4.0 with up to 255 network users. A single Ethernet network adapter is installed in the Pick system.
Pick System's R83:
PicLan supports Pick R83 releases 3.0 and 3.1 with up to 31 network users. A single Ethernet network adapter is installed in the Pick system.
Pick System's AP/Native:
PicLan supports Pick AP/Native releases 5.2.0 through 5.2.7 with up to 32 network users. A single Ethernet network adapter is installed in the Pick system.
Pick System's AP/Pro:
PicLan support Pick AP/Pro release 6.1 with up to 256 network users. A single Ethernet network adapter is installed in the Pick system.
Sanyo/Icon Upboard:
PicLan supports Upboard releases 92a and later with up to 127 network users. A single network adapter is installed in the Pick system. This adapter may be either an Ethernet adapter which PicLan programs directly, or other types of network adapters including ArcNET and Token-Ring when programmed with IPX or NDIS DOS device drivers.
Sequoia System's Sequoia PRO
PicLan supports Sequoia PRO release 2.4 with up to 190 network users. A single Ethernet network adapter is installed in the Pick system.

Network environments:

PicLan supports a number of different network environments. Configuration limitations and considerations do exist when PicLan is used in conjunction with some networks.

Novell Server-based Netware:

PicLan is compatible with all versions of server-based NetWare including 2.x, 3.x, and 4.x releases. DOS workstations operate directly with NetWare IPX drivers and do not require additional drivers or configuration. The Pick system can be connected to any media compatible network segment. PicLan traffic is compatible with both local and wide-area network routers.
Novell Peer-to-Peer NetWare:
PicLan is compatible with all versions of Peer-to-Peer NetWare including NetWare Lite, Personal NetWare, and DR-DOS 7. DOS workstations operate directly with NetWare IPX drivers and do not require additional drivers or configuration. Peer-to-Peer NetWare does not include router functions, so all DOS workstations and Pick servers must be connected to a single network media that is compatible with the Pick system unless after-market IPX routers are utilized.
Artisoft Lantastic:
Piclan is compatible with Lantastic version 5.0 AI with NDIS DOS driver support loaded running on Ethernet. DOS workstations operate with a PicLan NDIS driver stack loaded on each workstation. Lantastic does not support IPX routing, so all DOS workstations and Pick servers must be connected to a single Ethernet network media that is compatible with the Pick system unless after-market IPX routers are utilized. R91 systems require an ArcNET to Ethernet router.
Microsoft Windows Network:
PicLan is compatible with Windows for Workgroups versions 3.1 and 3.11 and Windows NT Advanced Server networks running on Ethernet. DOS workstations operate with a PicLan NDIS driver stack loaded on each workstation. Microsoft Windows Network does not include IPX routing functions, but after market routers may be used. R91 systems require an ArcNET to Ethernet router.
Other IPX Networks:
PicLan is compatible with DOS network drivers that implement the IPX API (Applications Programming Interface) including products like Spry Concurrent. Some PicLan DOS Services Gateway printer sharing functions may not be available with these networks.
Other NDIS Networks:
PicLan is compatible with other network systems that use DOS NDIS Ethernet network drivers. Some PicLan DOS Services Gateway printer sharing functions may not be available with these networks.
Other Packet-Driver Networks:
PicLan is compatible with other network systems that use Packet-Driver Ethernet or ArcNET network drivers. Some PicLan DOS Services Gateway printer sharing functions may not be available with these networks.
Native PicLan Network:
PicLan can run as a stand-alone network without any underlying DOS network. DOS workstations can run with PicLan, NDIS compatible, or Packet-Driver compatible Ethernet adapters or with Packet-Driver compatible ArcNET adapters. PicLan provides only Pick services to PicLan native networks, not DOS network services such as shared drives.

PicLan Technical Details

This information is provided for the benefit of network administrators who wish to know additional details about the Pick system they are about to connect to their network.

PicLan communicates with the local area network using a protocol called IPX (Internetwork Packet eXchange) which is a superset of XNS (Xerox Network Services). IPX is the most popular networking protocol in the world and is also the primary protocol that Novell NetWare uses. PicLan network traffic also uses SAP (Service Advertising Protocol) to enable network addressing and PicLan has dedicated "server-type" (0x03FF) and "socket number" (0x80E1) assignments from Novell. PicLan traffic and server advertising traffic are fully compatible with both local and wide-area networks through repeaters, bridges, and IPX routers.

PicLan implements it's own reliable connection layer mapped on top of IPX. This connection layer provides for very efficient network connections that are optimized for serial stream traffic generated asynchronously. PicLan connections exert very little overhead on the local area network even for a large numbers of active terminal users and are also very efficient for the Pick host system. PicLan connections usually are lower in overhead to the Pick host than the best serial controllers while producing less network traffic than async gateway products. PicLan handshaking has also been optimized for network environments that experience large numbers of errors (lost packets) and that have large transmission throughput delays such as are experienced with wide area packet-switched networks.

PicLan Ethernet Pick host implementations support four different Ethernet frame formats (all NetWare compatible). These frame formats (802.3, Ethernet-II, 802.2, and 802.2 SNAP) allow PicLan to be configured to match the local configuration without requiring workstation reconfigurations. The Piclan ArcNET host implementation for R91 implements the Novell RXNET IPX protocol.

PicLan workstation implementations support a number of networking architechures. PicLan can directly drive PicLan Ethernet adapters without the addition of any DOS driver software. PicLan can also utilize existing IPX drivers (either IPX.COM, IPXODI, third-party IPX drivers such as Spry Concurrent, and 32-bit Windows IPX drivers from Novell or Microsoft), NDIS Ethernet-II drivers (with Ethernet-II format frames), and Clarkson Packet-Driver format drivers (with ArcNET RXNET frames or Ethernet 802.3 or Ethernet-II format frames).

PicLan Installed Base

The PicLan product is very robust and supports even large user counts with a single network connection. Testing indicates that supporting in excess of 600 network users with a single Ethernet network connection is not technically difficult, even with a single network connection. Most PicLan installations are in the 8 to 32 users range. The largest production sites have just over 100 active users.

PicLan DOS Services Gateway functions are very flexible both in terms of file transfer and printer sharing functions. Users have applications running that do everything from controlling DOS-based fax servers to downloading files directly from networked mainframes (remember, if the DOS Services Gateway can access the file, then so can Pick). Some sites are using a PicLan DSG to move more than 100 Megabytes of data in a single batch. Several sites are also routing in excess of 35 printers through a single gateway system and one site is outbound spooling to 11 NetWare servers.

PicLan is compatible with both local and wide-area networks, provided that the network will move IPX format data packets. Sites exist that span the US, and even cross international borders. Most of the installations using wide-area networking with PicLan were installed without any interaction between the PicLan developers and the customer. If the network moves IPX traffic, then it moves PicLan traffic.

Most PicLan sites only have a single Pick system. A number of sites, particularly at dealer locations, support multiple Pick hosts to aid software development and source code control functions. This is particularly useful in that PicLan supports dissimilar hosts on a network. The largest end-user PicLan site with multiple Pick systems supports a five Pick system cluster running a mix of R83 and R91 systems. The R91 system use PicLan as a transport medium to support GALAN Pick to Pick functions in addition to PicLan Pick to Pick functions.